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/mod_perl/apache_1.3.23/htdocs/manual/misc/FAQ.html

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  5.   <head>
    6. 

  6.     <meta name="generator" content="HTML Tidy, see www.w3.org" />
    7. 

  7. 

  8.     <title>Apache Server Frequently Asked Questions</title>
    9. 

  9.     
    10. 

  10.   </head>
    11. 

  11.   <!-- Background white, links blue (unvisited), navy (visited), red (active) -->
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    15. 

  15.         <div align="CENTER">
    16. 

  16.       <img src="../images/sub.gif" alt="[APACHE DOCUMENTATION]" /> 
    17. 

  17. 

  18.       <h3>Apache HTTP Server Version 1.3</h3>
    19. 

  19.     </div>
    20. 

  20. 

  21. 

  22.     <h1 align="CENTER">Apache Server Frequently Asked
    23. 

  23.     Questions</h1>
    24. 

  24. 

  25.     <p>$Revision: 1.149 $ ($Date: 2001/10/08 01:26:54 $)</p>
    26. 

  26. 

  27.     <p>The latest version of this FAQ is always available from the
    28. 

  28.     main Apache web site, at &lt;<a
    29. 

  29.     href="http://httpd.apache.org/docs/misc/FAQ.html"
    30. 

  30.     rel="Help"><samp>http://httpd.apache.org/docs/misc/FAQ.html</samp></a>&gt;.</p>
    31. 

  31.     <!-- Notes about changes:                                           -->
    32. 

  32.     <!--  - If adding a relative link to another part of the            -->
    33. 

  33.     <!--    documentation, *do* include the ".html" portion.  There's a -->
    34. 

  34.     <!--    good chance that the user will be reading the documentation -->
    35. 

  35.     <!--    on his own system, which may not be configured for          -->
    36. 

  36.     <!--    multiviews.                                                 -->
    37. 

  37.     <!--  - When adding items, make sure they're put in the right place -->
    38. 

  38.     <!--    - verify that the numbering matches up.                     -->
    39. 

  39.     <!--  - *Don't* use <PRE></PRE> blocks - they don't appear          -->
    40. 

  40.     <!--    correctly in a reliable way when this is converted to text  -->
    41. 

  41.     <!--    with Lynx.  Use <DL><DD><CODE>xxx<BR>xx</CODE></DD></DL>    -->
    42. 

  42.     <!--    blocks inside a <P></P> instead.  This is necessary to get  -->
    43. 

  43.     <!--    the horizontal and vertical indenting right.                -->
    44. 

  44.     <!--  - Don't forget to include an HR tag after the last /P tag     -->
    45. 

  45.     <!--    but before the /LI in an item.                              -->
    46. 

  46. 

  47.     <p>If you are reading a text-only version of this FAQ, you may
    48. 

  48.     find numbers enclosed in brackets (such as "[12]"). These refer
    49. 

  49.     to the list of reference URLs to be found at the end of the
    50. 

  50.     document. These references do not appear, and are not needed,
    51. 

  51.     for the hypertext version.</p>
    52. 

  52. 

  53.     <h2>The Questions</h2>
    54. 

  54.     <!-- Stuff to Add:                                                  -->
    55. 

  55.     <!-- - can't bind to port 80                                        -->
    56. 

  56.     <!--   - permission denied                                          -->
    57. 

  57.     <!--   - address already in use                                     -->
    58. 

  58.     <!-- - mod_auth & passwd lines "user:pw:.*" - ++1st colon onward is -->
    59. 

  59.     <!--   treated as pw, not just ++1st to \-\-2nd.                    -->
    60. 

  60.     <!-- - SSL:                                                         -->
    61. 

  61.     <!--   - Can I use Apache-SSL for free in Canada?                   -->
    62. 

  62.     <!--   - Why can't I use Apache-SSL in the U.S.?                    -->
    63. 

  63.     <!-- - How can I found out how many visitors my site gets?          -->
    64. 

  64.     <!-- - How do I add a counter?                                      -->
    65. 

  65.     <!-- - How do I configure Apache as a proxy?                        -->
    66. 

  66.     <!-- - What browsers support HTTP/1.1?                              -->
    67. 

  67.     <!-- - What's the point of vhosts-by-name is there aren't any       -->
    68. 

  68.     <!--   HTTP/1.1 browsers?                                           -->
    69. 

  69.     <!-- - Is there an Apache for W95/WNT?                              -->
    70. 

  70.     <!-- - Why does Apache die when a vhost can't be DNS-resolved?      -->
    71. 

  71.     <!-- - Why do I get "send lost connection" messages in my error     -->
    72. 

  72.     <!--   log?                                                         -->
    73. 

  73.     <!--   - specifically consider .pdf files which seem to cause this  -->
    74. 

  74.     <!--     a lot when accessed via the plugin ... and also mention    -->
    75. 

  75.     <!--     how range-requests can cause bytes served < file size      -->
    76. 

  76.     <!-- - Why do directory indexes appear as garbage?  (A: -lucb)      -->
    77. 

  77.     <!-- - How do I add a footer to all pages offered by my server?     -->
    78. 

  78.     <!-- - Fix midi question; a bigger problem than midi vs. x-midi is  -->
    79. 

  79.     <!--   the simple fact that older versions of Apache (and new ones  -->
    80. 

  80.     <!--   that have been upgraded without upgrading the mime.types     -->
    81. 

  81.     <!--   file) don't have the type listed at all.                     -->
    82. 

  82.     <!-- - RewriteRule /~fraggle/* /cgi-bin/fraggle.pl does not work    -->
    83. 

  83.     <!-- - how do I disable authentication for a subdirectory?          -->
    84. 

  84.     <!--   (A: you can't but "Satisfy any; Allow from all" can be close -->
    85. 

  85.     <!-- - '400 malformed request' on Win32 might mean stale proxy; see -->
    86. 

  86.     <!--   PR #2300.                                                    -->
    87. 

  87.     <!-- - how do I tell what version of Apache I am running?           -->
    88. 

    89. 

  89.     <ol type="A">
    90. 

  90.       
    91. 

    92. 

    93. 

    94. 

    95. 

    96. 

    97. 

    98. 

    99. 

  99.       
    100. 

    101. 

  101.       <li value="1">
    102. 

  102.         <strong>Background</strong> 
    103. 

    104. 

  104.         <ol>
    105. 

  105.           <li><a href="#what">What is Apache?</a></li>
    106. 

    107. 

  107.           <li><a href="#why">How and why was Apache
    108. 

  108.           created?</a></li>
    109. 

    110. 

  110.           <li><a href="#name">Why the name "Apache"?</a></li>
    111. 

    112. 

  112.           <li><a href="#compare">OK, so how does Apache compare to
    113. 

  113.           other servers?</a></li>
    114. 

    115. 

  115.           <li><a href="#tested">How thoroughly tested is
    116. 

  116.           Apache?</a></li>
    117. 

    118. 

  118.           <li><a href="#future">What are the future plans for
    119. 

  119.           Apache?</a></li>
    120. 

    121. 

  121.           <li><a href="#support">Whom do I contact for
    122. 

  122.           support?</a></li>
    123. 

    124. 

  124.           <li><a href="#more">Is there any more information on
    125. 

  125.           Apache?</a></li>
    126. 

    127. 

  127.           <li><a href="#where">Where can I get Apache?</a></li>
    128. 

    129. 

  129.           <li><a href="#logo">May I use the Apache logo on my
    130. 

  130.           product or Web site?</a></li>
    131. 

  131.         </ol>
    132. 

  132.       </li>
    133. 

  133.       
    134. 

  134.       
    135. 

  135.     
    136. 

  136.     
    137. 

  137.   </body>
    138. 

  138. </html>
    139. 

    140. 

    141. 

  141.       
    142. 

    143. 

    144. 

    145. 

    146. 

    147. 

    148. 

    149. 

    150. 

  150.       
    151. 

    152. 

  152.       <li value="2">
    153. 

  153.         <strong>General Technical Questions</strong> 
    154. 

    155. 

  155.         <ol>
    156. 

  156.           <li><a href="#what2do">"Why can't I ...? Why won't ...
    157. 

  157.           work?" What to do in case of problems</a></li>
    158. 

    159. 

  159.           <li><a href="#compatible">How compatible is Apache with
    160. 

  160.           my existing NCSA 1.3 setup?</a></li>
    161. 

    162. 

  162.           <li><a href="#year2000">Is Apache Year 2000
    163. 

  163.           compliant?</a></li>
    164. 

    165. 

  165.           <li><a href="#submit_patch">How do I submit a patch to
    166. 

  166.           the Apache Group?</a></li>
    167. 

    168. 

  168.           <li><a href="#domination">Why has Apache stolen my
    169. 

  169.           favourite site's Internet address?</a></li>
    170. 

    171. 

  171.           <li><a href="#apspam">Why am I getting spam mail from the
    172. 

  172.           Apache site?</a></li>
    173. 

    174. 

  174.           <li><a href="#redist">May I include the Apache software
    175. 

  175.           on a CD or other package I'm distributing?</a></li>
    176. 

    177. 

  177.           <li><a href="#zoom">What's the best hardware/operating
    178. 

  178.           system/... How do I get the most out of my Apache Web
    179. 

  179.           server?</a></li>
    180. 

    181. 

  181.           <li><a href="#regex">What are "regular
    182. 

  182.           expressions"?</a></li>
    183. 

    184. 

  184.           <li><a href="#binaries">Why isn't there a binary for my
    185. 

  185.           platform?</a></li>
    186. 

  186.         </ol>
    187. 

  187.       </li>
    188. 

  188.       
    189. 

  189.       
    190. 

  190.     
    191. 

  191.     
    192. 

  192.   </body>
    193. 

  193. </html>
    194. 

    195. 

    196. 

  196.       
    197. 

    198. 

    199. 

    200. 

    201. 

    202. 

    203. 

    204. 

    205. 

  205.       
    206. 

    207. 

  207.       <li value="3">
    208. 

  208.         <strong>Building Apache</strong> 
    209. 

    210. 

  210.         <ol>
    211. 

  211.           <li><a href="#bind8.1">Why do I get an error about an
    212. 

  212.           undefined reference to "<samp>__inet_ntoa</samp>" or
    213. 

  213.           other <samp>__inet_*</samp> symbols?</a></li>
    214. 

    215. 

  215.           <li><a href="#cantbuild">Why won't Apache compile with my
    216. 

  216.           system's <samp>cc</samp>?</a></li>
    217. 

    218. 

  218.           <li><a href="#linuxiovec">Why do I get complaints about
    219. 

  219.           redefinition of "<code>struct iovec</code>" when
    220. 

  220.           compiling under Linux?</a></li>
    221. 

    222. 

  222.           <li><a href="#broken-gcc">I'm using gcc and I get some
    223. 

  223.           compilation errors, what is wrong?</a></li>
    224. 

    225. 

  225.           <li><a href="#glibc-crypt">I'm using RedHat Linux 5.0, or
    226. 

  226.           some other <samp>glibc</samp>-based Linux system, and I
    227. 

  227.           get errors with the <code>crypt</code> function when I
    228. 

  228.           attempt to build Apache 1.2.</a></li>
    229. 

  229.         </ol>
    230. 

  230.       </li>
    231. 

  231.       
    232. 

  232.       
    233. 

  233.     
    234. 

  234.     
    235. 

  235.   </body>
    236. 

  236. </html>
    237. 

    238. 

    239. 

  239.       
    240. 

    241. 

    242. 

    243. 

    244. 

    245. 

    246. 

    247. 

    248. 

  248.       
    249. 

    250. 

  250.       <li value="4">
    251. 

  251.         <strong>Error Log Messages and Problems Starting
    252. 

  252.         Apache</strong> 
    253. 

    254. 

  254.         <ol>
    255. 

  255.           <li><a href="#setgid">Why do I get "<samp>setgid: Invalid
    256. 

  256.           argument</samp>" at startup?</a></li>
    257. 

    258. 

  258.           <li><a href="#nodelay">Why am I getting "<samp>httpd:
    259. 

  259.           could not set socket option TCP_NODELAY</samp>" in my
    260. 

  260.           error log?</a></li>
    261. 

    262. 

  262.           <li><a href="#peerreset">Why am I getting
    263. 

  263.           "<samp>connection reset by peer</samp>" in my error
    264. 

  264.           log?</a></li>
    265. 

    266. 

  266.           <li><a href="#wheres-the-dump">The errorlog says Apache
    267. 

  267.           dumped core, but where's the dump file?</a></li>
    268. 

    269. 

  269.           <li><a href="#linux-shmget">When I run it under Linux I
    270. 

  270.           get "shmget: function not found", what should I
    271. 

  271.           do?</a></li>
    272. 

    273. 

  273.           <li><a href="#nfslocking">Server hangs, or fails to
    274. 

  274.           start, and/or error log fills with "<samp>fcntl:
    275. 

  275.           F_SETLKW: No record locks available</samp>" or similar
    276. 

  276.           messages</a></li>
    277. 

    278. 

  278.           <li><a href="#aixccbug">Why am I getting "<samp>Expected
    279. 

  279.           &lt;/Directory&gt; but saw &lt;/Directory&gt;</samp>"
    280. 

  280.           when I try to start Apache?</a></li>
    281. 

    282. 

  282.           <li><a href="#redhat">I'm using RedHat Linux and I have
    283. 

  283.           problems with httpd dying randomly or not restarting
    284. 

  284.           properly</a></li>
    285. 

    286. 

  286.           <li><a href="#stopping">I upgraded from an Apache version
    287. 

  287.           earlier than 1.2.0 and suddenly I have problems with
    288. 

  288.           Apache dying randomly or not restarting properly</a></li>
    289. 

    290. 

  290.           <li><a href="#setservername">When I try to start Apache
    291. 

  291.           from a DOS window, I get a message like "<samp>Cannot
    292. 

  292.           determine host name. Use ServerName directive to set it
    293. 

  293.           manually.</samp>" What does this mean?</a></li>
    294. 

    295. 

  295.           <li><a href="#ws2_32dll">When I try to start Apache for
    296. 

  296.           Windows, I get a message like "<samp>Unable To Locate
    297. 

  297.           WS2_32.DLL...</samp>". What should I do?</a></li>
    298. 

    299. 

  299.           <li><a href="#WSADuplicateSocket">Apache for Windows does
    300. 

  300.           not start. Error log contains this message "<samp>[crit]
    301. 

  301.           (10045) The attempted operation is not supported for the
    302. 

  302.           type of object referenced: Parent: WSADuplicateSocket
    303. 

  303.           failed for socket ###</samp>". What does this
    304. 

  304.           mean?</a></li>
    305. 

    306. 

  306.           <li><a href="#err1067">When I try to start Apache on
    307. 

  307.           Windows, I get a message like "<code>System error 1067
    308. 

  308.           has occurred. The process terminated
    309. 

  309.           unexpectedly.</code>" What does this mean?</a></li>
    310. 

    311. 

  311.           <li><a href="#suseFDN">On a SuSE Linux system, I try and 
    312. 

  312.           configure access control using basic authentication.
    313. 

  313. 	  Although I follow the example exactly, authentication
    314. 

  314. 	  fails, and an error message "<code>admin: not a valid
    315. 

  315. 	  FDN: ....</code>" is logged.</a></li>
    316. 

    317. 

  317.           <li><a href="#codered">Why do I have weird entries in my
    318. 

  318.           logs asking for <code>default.ida</code> and
    319. 

  319.           <code>cmd.exe</code>?</a></li>
    320. 

  320.         </ol>
    321. 

  321.       </li>
    322. 

  322.       
    323. 

  323.       
    324. 

  324.     
    325. 

  325.     
    326. 

  326.   </body>
    327. 

  327. </html>
    328. 

    329. 

    330. 

  330.       
    331. 

    332. 

    333. 

    334. 

    335. 

    336. 

    337. 

    338. 

    339. 

  339.       
    340. 

    341. 

  341.       <li value="5">
    342. 

  342.         <strong>Configuration Questions</strong> 
    343. 

    344. 

  344.         <ol>
    345. 

  345.           <li><a href="#fdlim">Why can't I run more than
    346. 

  346.           &lt;<em>n</em>&gt; virtual hosts?</a></li>
    347. 

    348. 

  348.           <li><a href="#freebsd-setsize">Can I increase
    349. 

  349.           <samp>FD_SETSIZE</samp> on FreeBSD?</a></li>
    350. 

    351. 

  351.           <li><a href="#errordoc401">Why doesn't my
    352. 

  352.           <code>ErrorDocument 401</code> work?</a></li>
    353. 

    354. 

  354.           <li><a href="#cookies1">Why does Apache send a cookie on
    355. 

  355.           every response?</a></li>
    356. 

    357. 

  357.           <li><a href="#cookies2">Why don't my cookies work, I even
    358. 

  358.           compiled in <samp>mod_cookies</samp>?</a></li>
    359. 

    360. 

  360.           <li><a href="#jdk1-and-http1.1">Why do my Java app[let]s
    361. 

  361.           give me plain text when I request an URL from an Apache
    362. 

  362.           server?</a></li>
    363. 

    364. 

  364.           <li><a href="#midi">How do I get Apache to send a MIDI
    365. 

  365.           file so the browser can play it?</a></li>
    366. 

    367. 

  367.           <li><a href="#addlog">How do I add browsers and referrers
    368. 

  368.           to my logs?</a></li>
    369. 

    370. 

  370.           <li><a href="#set-servername">Why does accessing
    371. 

  371.           directories only work when I include the trailing "/"
    372. 

  372.           (<em>e.g.</em>,&nbsp;<samp>http://foo.domain.com/~user/</samp>)
    373. 

  373.           but not when I omit it
    374. 

  374.           (<em>e.g.</em>,&nbsp;<samp>http://foo.domain.com/~user</samp>)?</a></li>
    375. 

    376. 

  376.           <li><a href="#no-info-directives">Why doesn't mod_info
    377. 

  377.           list any directives?</a></li>
    378. 

    379. 

  379.           <li><a href="#namevhost">I upgraded to Apache 1.3 and now
    380. 

  380.           my virtual hosts don't work!</a></li>
    381. 

    382. 

  382.           <li><a href="#redhat-htm">I'm using RedHat Linux and my
    383. 

  383.           .htm files are showing up as HTML source rather than
    384. 

  384.           being formatted!</a></li>
    385. 

    386. 

  386.           <li><a href="#htaccess-work">My <code>.htaccess</code>
    387. 

  387.           files are being ignored.</a></li>
    388. 

    389. 

  389.           <li><a href="#forbidden">Why do I get a
    390. 

  390.           "<samp>Forbidden</samp>" message whenever I try to access
    391. 

  391.           a particular directory?</a></li>
    392. 

    393. 

  393.           <li><a href="#malfiles">Why do I get a
    394. 

  394.           "<samp>Forbidden/You don't have permission to access / on
    395. 

  395.           this server</samp>" message whenever I try to access my
    396. 

  396.           server?</a></li>
    397. 

    398. 

  398.           <li><a href="#ie-ignores-mime">Why do my files appear
    399. 

  399.           correctly in Internet Explorer, but show up as source or
    400. 

  400.           trigger a save window with Netscape?</a></li>
    401. 

    402. 

  402. 	  <li><a href="#canonical-hostnames">My site is accessible
    403. 

  403.           under many different hostnames; how do I redirect clients
    404. 

  404.           so that they see only a single name?</a></li>
    405. 

    406. 

  406.           <li><a href="#firewall">Why can I access my website from the
    407. 

  407.           server or from my local network, but I can't access it from
    408. 

  408.           elsewhere on the Internet?</a></li>
    409. 

    410. 

  410.         </ol>
    411. 

  411.       </li>
    412. 

  412.       
    413. 

  413.       
    414. 

  414.     
    415. 

  415.     
    416. 

  416.   </body>
    417. 

  417. </html>
    418. 

    419. 

    420. 

  420.       
    421. 

    422. 

    423. 

    424. 

    425. 

    426. 

    427. 

    428. 

    429. 

  429.       
    430. 

    431. 

  431.       <li value="6">
    432. 

  432.         <strong>Dynamic Content (CGI and SSI)</strong> 
    433. 

    434. 

  434.         <ol>
    435. 

  435.           <li><a href="#CGIoutsideScriptAlias">How do I enable CGI
    436. 

  436.           execution in directories other than the
    437. 

  437.           ScriptAlias?</a></li>
    438. 

    439. 

  439.           <li><a href="#premature-script-headers">What does it mean
    440. 

  440.           when my CGIs fail with "<samp>Premature end of script
    441. 

  441.           headers</samp>"?</a></li>
    442. 

    443. 

  443.           <li><a href="#POSTnotallowed">Why do I keep getting
    444. 

  444.           "Method Not Allowed" for form POST requests?</a></li>
    445. 

    446. 

  446.           <li><a href="#nph-scripts">How can I get my script's
    447. 

  447.           output without Apache buffering it? Why doesn't my server
    448. 

  448.           push work?</a></li>
    449. 

    450. 

  450.           <li><a href="#cgi-spec">Where can I find the "CGI
    451. 

  451.           specification"?</a></li>
    452. 

    453. 

  453.           <li><a href="#fastcgi">Why isn't FastCGI included with
    454. 

  454.           Apache any more?</a></li>
    455. 

    456. 

  456.           <li><a href="#ssi-part-i">How do I enable SSI (parsed
    457. 

  457.           HTML)?</a></li>
    458. 

    459. 

  459.           <li><a href="#ssi-part-ii">Why don't my parsed files get
    460. 

  460.           cached?</a></li>
    461. 

    462. 

  462.           <li><a href="#ssi-part-iii">How can I have my script
    463. 

  463.           output parsed?</a></li>
    464. 

    465. 

  465.           <li><a href="#ssi-part-iv">SSIs don't work for
    466. 

  466.           VirtualHosts and/or user home directories</a></li>
    467. 

    468. 

  468.           <li><a href="#errordocssi">How can I use
    469. 

  469.           <code>ErrorDocument</code> and SSI to simplify customized
    470. 

  470.           error messages?</a></li>
    471. 

    472. 

  472.           <li><a href="#remote-user-var">Why is the environment
    473. 

  473.           variable <samp>REMOTE_USER</samp> not set?</a></li>
    474. 

    475. 

  475.           <li><a href="#user-cgi">How do I allow each of my user
    476. 

  476.           directories to have a cgi-bin directory?</a></li>
    477. 

  477.         </ol>
    478. 

  478.       </li>
    479. 

  479.       
    480. 

  480.       
    481. 

  481.     
    482. 

  482.     
    483. 

  483.   </body>
    484. 

  484. </html>
    485. 

    486. 

    487. 

  487.       
    488. 

    489. 

    490. 

    491. 

    492. 

    493. 

    494. 

    495. 

    496. 

  496.       
    497. 

    498. 

  498.       <li value="7">
    499. 

  499.         <strong>Authentication and Access Restrictions</strong> 
    500. 

    501. 

  501.         <ol>
    502. 

  502.           <li><a href="#dnsauth">Why isn't restricting access by
    503. 

  503.           host or domain name working correctly?</a></li>
    504. 

    505. 

  505.           <li><a href="#user-authentication">How do I set up Apache
    506. 

  506.           to require a username and password to access certain
    507. 

  507.           documents?</a></li>
    508. 

    509. 

  509.           <li><a href="#remote-auth-only">How do I set up Apache to
    510. 

  510.           allow access to certain documents only if a site is
    511. 

  511.           either a local site <em>or</em> the user supplies a
    512. 

  512.           password and username?</a></li>
    513. 

    514. 

  514.           <li><a href="#authauthoritative">Why does my
    515. 

  515.           authentication give me a server error?</a></li>
    516. 

    517. 

  517.           <li><a href="#auth-on-same-machine">Do I have to keep the
    518. 

  518.           (mSQL) authentication information on the same
    519. 

  519.           machine?</a></li>
    520. 

    521. 

  521.           <li><a href="#msql-slow">Why is my mSQL authentication
    522. 

  522.           terribly slow?</a></li>
    523. 

    524. 

  524.           <li><a href="#passwdauth">Can I use my
    525. 

  525.           <samp>/etc/passwd</samp> file for Web page
    526. 

  526.           authentication?</a></li>
    527. 

    528. 

  528.           <li><a href="#prompted-twice">Why does Apache ask for my
    529. 

  529.           password twice before serving a file?</a></li>
    530. 

  530.         </ol>
    531. 

  531.       </li>
    532. 

  532.       
    533. 

  533.       
    534. 

  534.     
    535. 

  535.     
    536. 

  536.   </body>
    537. 

  537. </html>
    538. 

    539. 

    540. 

  540.       
    541. 

    542. 

    543. 

    544. 

    545. 

    546. 

    547. 

    548. 

    549. 

  549.       
    550. 

    551. 

  551.       <li value="8">
    552. 

  552.         <strong>URL Rewriting</strong> 
    553. 

    554. 

  554.         <ol>
    555. 

  555.           <li><a href="#rewrite-more-config">Where can I find
    556. 

  556.           mod_rewrite rulesets which already solve particular
    557. 

  557.           URL-related problems?</a></li>
    558. 

    559. 

  559.           <li><a href="#rewrite-article">Where can I find any
    560. 

  560.           published information about URL-manipulations and
    561. 

  561.           mod_rewrite?</a></li>
    562. 

    563. 

  563.           <li><a href="#rewrite-complexity">Why is mod_rewrite so
    564. 

  564.           difficult to learn and seems so complicated?</a></li>
    565. 

    566. 

  566.           <li><a href="#rewrite-dontwork">What can I do if my
    567. 

  567.           RewriteRules don't work as expected?</a></li>
    568. 

    569. 

  569.           <li><a href="#rewrite-prefixdocroot">Why don't some of my
    570. 

  570.           URLs get prefixed with DocumentRoot when using
    571. 

  571.           mod_rewrite?</a></li>
    572. 

    573. 

  573.           <li><a href="#rewrite-nocase">How can I make all my URLs
    574. 

  574.           case-insensitive with mod_rewrite?</a></li>
    575. 

    576. 

  576.           <li><a href="#rewrite-virthost">Why are RewriteRules in
    577. 

  577.           my VirtualHost parts ignored?</a></li>
    578. 

    579. 

  579.           <li><a href="#rewrite-envwhitespace">How can I use
    580. 

  580.           strings with whitespaces in RewriteRule's ENV
    581. 

  581.           flag?</a></li>
    582. 

  582.         </ol>
    583. 

  583.       </li>
    584. 

  584.       
    585. 

  585.       
    586. 

  586.     
    587. 

  587.     
    588. 

  588.   </body>
    589. 

  589. </html>
    590. 

    591. 

    592. 

  592.       
    593. 

    594. 

    595. 

    596. 

    597. 

    598. 

    599. 

    600. 

    601. 

  601.       
    602. 

    603. 

  603.       <li value="9">
    604. 

  604.         <strong>Features</strong> 
    605. 

    606. 

  606.         <ol>
    607. 

  607.           <li><a href="#proxy">Does or will Apache act as a Proxy
    608. 

  608.           server?</a></li>
    609. 

    610. 

  610.           <li><a href="#multiviews">What are "multiviews"?</a></li>
    611. 

    612. 

  612.           <li><a href="#putsupport">Why can't I publish to my
    613. 

  613.           Apache server using PUT on Netscape Gold and other
    614. 

  614.           programs?</a></li>
    615. 

    616. 

  616.           <li><a href="#SSL-i">Why doesn't Apache include
    617. 

  617.           SSL?</a></li>
    618. 

    619. 

  619.           <li><a href="#footer">How can I attach a footer to my
    620. 

  620.           documents without using SSI?</a></li>
    621. 

    622. 

  622.           <li><a href="#search">Does Apache include a search
    623. 

  623.           engine?</a></li>
    624. 

    625. 

  625.           <li><a href="#rotate">How can I rotate my log
    626. 

  626.           files?</a></li>
    627. 

    628. 

  628.           <li><a href="#conditional-logging">How do I keep certain
    629. 

  629.           requests from appearing in my logs?</a></li>
    630. 

    631. 

  631.           <li><a href="#dbinteg">Does Apache include any sort of
    632. 

  632.           database integration?</a></li>
    633. 

    634. 

  634.           <li><a href="#asp">Can I use Active Server Pages (ASP)
    635. 

  635.           with Apache?</a></li>
    636. 

    637. 

  637.           <li><a href="#java">Does Apache come with Java
    638. 

  638.           support?</a></li>
    639. 

  639.         </ol>
    640. 

  640.       </li>
    641. 

  641.       
    642. 

  642.       
    643. 

  643.     
    644. 

  644.     
    645. 

  645.   </body>
    646. 

  646. </html>
    647. 

    648. 

    649. 

  649.     </ol>
    650. 

  650.     <hr />
    651. 

    652. 

  652.     <h2>The Answers</h2>
    653. 

  653.     
    654. 

    655. 

    656. 

    657. 

    658. 

    659. 

    660. 

    661. 

    662. 

  662.       
    663. 

  663.       
    664. 

  664.     
    665. 

    666. 

  666.     <h3>A. Background</h3>
    667. 

    668. 

  668.     <ol>
    669. 

  669.       <li>
    670. 

  670.         <a id="what" name="what"><strong>What is
    671. 

  671.         Apache?</strong></a> 
    672. 

    673. 

  673.         <p>The Apache httpd server</p>
    674. 

    675. 

  675.         <ul>
    676. 

  676.           <li>is a powerful, flexible, HTTP/1.1 compliant web
    677. 

  677.           server</li>
    678. 

    679. 

  679.           <li>implements the latest protocols, including HTTP/1.1
    680. 

  680.           (RFC2616)</li>
    681. 

    682. 

  682.           <li>is highly configurable and extensible with
    683. 

  683.           third-party modules</li>
    684. 

    685. 

  685.           <li>can be customised by writing 'modules' using the
    686. 

  686.           Apache module API</li>
    687. 

    688. 

  688.           <li>provides full source code and comes with an
    689. 

  689.           unrestrictive license</li>
    690. 

    691. 

  691.           <li>runs on Windows NT/9x, Netware 5.x, OS/2, and most
    692. 

  692.           versions of Unix, as well as several other operating
    693. 

  693.           systems</li>
    694. 

    695. 

  695.           <li>is actively being developed</li>
    696. 

    697. 

  697.           <li>encourages user feedback through new ideas, bug
    698. 

  698.           reports and patches</li>
    699. 

    700. 

  700.           <li>
    701. 

  701.             implements many frequently requested features,
    702. 

  702.             including:<br />
    703. 

  703.             <br />
    704. 

  704.              
    705. 

    706. 

  706.             <dl>
    707. 

  707.               <dt>DBM databases for authentication</dt>
    708. 

    709. 

  709.               <dd>allows you to easily set up password-protected
    710. 

  710.               pages with enormous numbers of authorized users,
    711. 

  711.               without bogging down the server.</dd>
    712. 

    713. 

  713.               <dt>Customized responses to errors and problems</dt>
    714. 

    715. 

  715.               <dd>Allows you to set up files, or even CGI scripts,
    716. 

  716.               which are returned by the server in response to
    717. 

  717.               errors and problems, e.g. setup a script to intercept
    718. 

  718.               <strong>500 Server Error</strong>s and perform
    719. 

  719.               on-the-fly diagnostics for both users and
    720. 

  720.               yourself.</dd>
    721. 

    722. 

  722.               <dt>Multiple DirectoryIndex directives</dt>
    723. 

    724. 

  724.               <dd>Allows you to say <code>DirectoryIndex index.html
    725. 

  725.               index.cgi</code>, which instructs the server to
    726. 

  726.               either send back <code>index.html</code> or run
    727. 

  727.               <code>index.cgi</code> when a directory URL is
    728. 

  728.               requested, whichever it finds in the directory.</dd>
    729. 

    730. 

  730.               <dt>Unlimited flexible URL rewriting and
    731. 

  731.               aliasing</dt>
    732. 

    733. 

  733.               <dd>Apache has no fixed limit on the numbers of
    734. 

  734.               Aliases and Redirects which may be declared in the
    735. 

  735.               config files. In addition, a powerful rewriting
    736. 

  736.               engine can be used to solve most URL manipulation
    737. 

  737.               problems.</dd>
    738. 

    739. 

  739.               <dt>Content negotiation</dt>
    740. 

    741. 

  741.               <dd>i.e. the ability to automatically serve clients
    742. 

  742.               of varying sophistication and HTML level compliance,
    743. 

  743.               with documents which offer the best representation of
    744. 

  744.               information that the client is capable of
    745. 

  745.               accepting.</dd>
    746. 

    747. 

  747.               <dt>Virtual Hosts</dt>
    748. 

    749. 

  749.               <dd>A much requested feature, sometimes known as
    750. 

  750.               multi-homed servers. This allows the server to
    751. 

  751.               distinguish between requests made to different IP
    752. 

  752.               addresses or names (mapped to the same machine).
    753. 

  753.               Apache also offers dynamically configurable
    754. 

  754.               mass-virtual hosting.</dd>
    755. 

    756. 

  756.               <dt>Configurable Reliable Piped Logs</dt>
    757. 

    758. 

  758.               <dd>You can configure Apache to generate logs in the
    759. 

  759.               format that you want. In addition, on most Unix
    760. 

  760.               architectures, Apache can send log files to a pipe,
    761. 

  761.               allowing for log rotation, hit filtering, real-time
    762. 

  762.               splitting of multiple vhosts into separate logs, and
    763. 

  763.               asynchronous DNS resolving on the fly.</dd>
    764. 

  764.             </dl>
    765. 

  765.           </li>
    766. 

  766.         </ul>
    767. 

  767.         <hr />
    768. 

  768.       </li>
    769. 

    770. 

  770.       <li>
    771. 

  771.         <a id="why" name="why"><strong>How and why was Apache
    772. 

  772.         created?</strong></a> 
    773. 

    774. 

  774.         <p>The <a
    775. 

  775.         href="http://httpd.apache.org/ABOUT_APACHE.html">About
    776. 

  776.         Apache</a> document explains how the Apache project evolved
    777. 

  777.         from its beginnings as an outgrowth of the NCSA httpd
    778. 

  778.         project to its current status as one of the fastest, most
    779. 

  779.         efficient, and most functional web servers in
    780. 

  780.         existence.</p>
    781. 

  781.         <hr />
    782. 

  782.       </li>
    783. 

    784. 

  784.       <li>
    785. 

  785.         <a id="name" name="name"><strong>Why the name
    786. 

  786.         "Apache"?</strong></a> 
    787. 

    788. 

  788.         <p>A cute name which stuck. Apache is "<strong>A
    789. 

  789.         PA</strong>t<strong>CH</strong>y server". It was based on
    790. 

  790.         some existing code and a series of "patch files".</p>
    791. 

    792. 

  792.         <p>For many developers it is also a reverent connotation to
    793. 

  793.         the Native American Indian tribe of Apache, <a
    794. 

  794.         href="http://www.indians.org/welker/apache.htm">well-known
    795. 

  795.         for their superior skills in warfare strategy and
    796. 

  796.         inexhaustible endurance</a>. For more information on the
    797. 

  797.         Apache Nation, we suggest searching <a
    798. 

  798.         href="http://www.google.com/search?q=Apache+Nation">Google</a>,
    799. 

  799.         <a
    800. 

  800.         href="http://www.northernlight.com/nlquery.fcg?qr=Apache+Nation">
    801. 

  801.         Northernlight</a>, or <a
    802. 

  802.         href="http://www.alltheweb.com/cgi-bin/asearch?query=Apache+Nation">
    803. 

  803.         AllTheWeb</a>.</p>
    804. 

  804.         <hr />
    805. 

  805.       </li>
    806. 

    807. 

  807.       <li>
    808. 

  808.         <a id="compare" name="compare"><strong>OK, so how does
    809. 

  809.         Apache compare to other servers?</strong></a> 
    810. 

    811. 

  811.         <p>For an independent assessment, see <a
    812. 

  812.         href="http://webcompare.internet.com/">Web
    813. 

  813.         Compare</a>.</p>
    814. 

    815. 

  815.         <p>Apache has been shown to be substantially faster, more
    816. 

  816.         stable, and more feature-full than many other web servers.
    817. 

  817.         Although certain commercial servers have claimed to surpass
    818. 

  818.         Apache's speed (it has not been demonstrated that any of
    819. 

  819.         these "benchmarks" are a good way of measuring WWW server
    820. 

  820.         speed at any rate), we feel that it is better to have a
    821. 

  821.         mostly-fast free server than an extremely-fast server that
    822. 

  822.         costs thousands of dollars. Apache is run on sites that get
    823. 

  823.         millions of hits per day, and they have experienced no
    824. 

  824.         performance difficulties.</p>
    825. 

  825.         <hr />
    826. 

  826.       </li>
    827. 

    828. 

  828.       <li>
    829. 

  829.         <a id="tested" name="tested"><strong>How thoroughly tested
    830. 

  830.         is Apache?</strong></a> 
    831. 

    832. 

  832.         <p>Apache is run on over 6 million Internet servers (as of
    833. 

  833.         February 2000). It has been tested thoroughly by both
    834. 

  834.         developers and users. The Apache Group maintains rigorous
    835. 

  835.         standards before releasing new versions of their server,
    836. 

  836.         and our server runs without a hitch on over one half of all
    837. 

  837.         WWW servers available on the Internet. When bugs do show
    838. 

  838.         up, we release patches and new versions as soon as they are
    839. 

  839.         available.</p>
    840. 

  840.         <hr />
    841. 

  841.       </li>
    842. 

    843. 

  843.       <li>
    844. 

  844.         <a id="future" name="future"><strong>What are the future
    845. 

  845.         plans for Apache?</strong></a> 
    846. 

    847. 

  847.         <ul>
    848. 

  848.           <li>to continue to be an "open source" no-charge-for-use
    849. 

  849.           HTTP server,</li>
    850. 

    851. 

  851.           <li>to keep up with advances in HTTP protocol and web
    852. 

  852.           developments in general,</li>
    853. 

    854. 

  854.           <li>to collect suggestions for fixes/improvements from
    855. 

  855.           its users,</li>
    856. 

    857. 

  857.           <li>to respond to needs of large volume providers as well
    858. 

  858.           as occasional users.</li>
    859. 

  859.         </ul>
    860. 

  860.         <hr />
    861. 

  861.       </li>
    862. 

    863. 

  863.       <li>
    864. 

  864.         <a id="support" name="support"><strong>Whom do I contact
    865. 

  865.         for support?</strong></a> 
    866. 

    867. 

  867.         <p>There is no official support for Apache. None of the
    868. 

  868.         developers want to be swamped by a flood of trivial
    869. 

  869.         questions that can be resolved elsewhere. Bug reports and
    870. 

  870.         suggestions should be sent <em>via</em> <a
    871. 

  871.         href="http://httpd.apache.org/bug_report.html">the bug
    872. 

  872.         report page</a>. Other questions should be directed to the
    873. 

  873.         <a href="http://httpd.apache.org/userslist.html">Apache HTTP
    874. 

  874.         Server Users List</a> or the
    875. 

  875.         <a
    876. 

  876.         href="news:comp.infosystems.www.servers.unix">comp.infosystems.www.servers.unix</a>
    877. 

  877.         or <a
    878. 

  878.         href="news:comp.infosystems.www.servers.ms-windows">comp.infosystems.www.servers.ms-windows</a>
    879. 

  879.         newsgroup (as appropriate for the platform you use), where
    880. 

  880.         some of the Apache team lurk, in the company of many other
    881. 

  881.         httpd gurus who should be able to help.</p>
    882. 

    883. 

  883.         <p>Commercial support for Apache is, however, available
    884. 

  884.         from a number of third parties.</p>
    885. 

  885.         <hr />
    886. 

  886.       </li>
    887. 

    888. 

  888.       <li>
    889. 

  889.         <a id="more" name="more"><strong>Is there any more
    890. 

  890.         information available on Apache?</strong></a> 
    891. 

    892. 

  892.         <p>Indeed there is. See the main <a
    893. 

  893.         href="http://httpd.apache.org/">Apache web site</a>. There
    894. 

  894.         is also a regular electronic publication called <a
    895. 

  895.         href="http://www.apacheweek.com/" rel="Help"><cite>Apache
    896. 

  896.         Week</cite></a> available. Links to relevant <cite>Apache
    897. 

  897.         Week</cite> articles are included below where appropriate.
    898. 

  898.         There are also some <a
    899. 

  899.         href="http://httpd.apache.org/info/apache_books.html">Apache-specific
    900. 

  900.         books</a> available.</p>
    901. 

  901.         <hr />
    902. 

  902.       </li>
    903. 

    904. 

  904.       <li>
    905. 

  905.         <a id="where" name="where"><strong>Where can I get
    906. 

  906.         Apache?</strong></a> 
    907. 

    908. 

  908.         <p>You can find out how to download the source for Apache
    909. 

  909.         at the project's <a href="http://httpd.apache.org/">main
    910. 

  910.         web page</a>.</p>
    911. 

  911.         <hr />
    912. 

  912.       </li>
    913. 

    914. 

  914.       <li>
    915. 

  915.         <a id="logo" name="logo"><b>May I use the Apache logo on my
    916. 

  916.         product or Web site?</b></a> 
    917. 

    918. 

  918.         <p>You may <b>NOT</b> use any original artwork from the
    919. 

  919.         Apache Software Foundation, nor make or use modified
    920. 

  920.         versions of such artwork, except under the following
    921. 

  921.         conditions:</p>
    922. 

    923. 

  923.         <ul>
    924. 

  924.           <li>You may use the <a
    925. 

  925.           href="../../apache_pb.gif">'Powered by Apache'
    926. 

  926.           graphic</a> on a Web site that is being served by the
    927. 

  927.           Apache HTTP server software.</li>
    928. 

    929. 

  929.           <li>You may use the aforementioned 'Powered by Apache'
    930. 

  930.           graphic or the <a
    931. 

  931.           href="http://www.apache.org/images/asf_logo.gif">
    932. 

  932.           Apache Software Foundation logo</a> in product
    933. 

  933.           description and promotional material <b>IF and ONLY
    934. 

  934.           IF</b> such use can in no way be interpreted as anything
    935. 

  935.           other than an attribution. Using the Apache name and
    936. 

  936.           artwork in a manner that implies endorsement of a product
    937. 

  937.           or service is <b>strictly forbidden</b>.</li>
    938. 

  938.         </ul>
    939. 

  939.         <hr />
    940. 

  940.       </li>
    941. 

  941.     </ol>
    942. 

  942.     
    943. 

  943.     
    944. 

  944.   </body>
    945. 

  945. </html>
    946. 

    947. 

    948. 

  948.     
    949. 

    950. 

    951. 

    952. 

    953. 

    954. 

    955. 

    956. 

    957. 

  957.       
    958. 

  958.       
    959. 

  959.     
    960. 

    961. 

  961.     <h3>B. General Technical Questions</h3>
    962. 

    963. 

  963.     <ol>
    964. 

  964.       <li>
    965. 

  965.         <a id="what2do" name="what2do"><strong>"Why can't I ...?
    966. 

  966.         Why won't ... work?" What to do in case of
    967. 

  967.         problems</strong></a> 
    968. 

    969. 

  969.         <p>If you are having trouble with your Apache server
    970. 

  970.         software, you should take the following steps:</p>
    971. 

    972. 

  972.         <ol>
    973. 

  973.           <li>
    974. 

  974.             <strong>Check the errorlog!</strong> 
    975. 

    976. 

  976.             <p>Apache tries to be helpful when it encounters a
    977. 

  977.             problem. In many cases, it will provide some details by
    978. 

  978.             writing one or messages to the server error log.
    979. 

  979.             Sometimes this is enough for you to diagnose &amp; fix
    980. 

  980.             the problem yourself (such as file permissions or the
    981. 

  981.             like). The default location of the error log is
    982. 

  982.             <samp>/usr/local/apache/logs/error_log</samp>, but see
    983. 

  983.             the <a
    984. 

  984.             href="../mod/core.html#errorlog"><samp>ErrorLog</samp></a>
    985. 

  985.             directive in your config files for the location on your
    986. 

  986.             server.</p>
    987. 

  987.           </li>
    988. 

    989. 

  989.           <li>
    990. 

  990.             <strong>Check the <a
    991. 

  991.             href="http://httpd.apache.org/docs/misc/FAQ.html">FAQ</a>!</strong>
    992. 

  992.             
    993. 

    994. 

  994.             <p>The latest version of the Apache Frequently-Asked
    995. 

  995.             Questions list can always be found at the main Apache
    996. 

  996.             web site.</p>
    997. 

  997.           </li>
    998. 

    999. 

  999.           <li>
    1000. 

  1000.             <strong>Check the Apache bug database</strong> 
    1001. 

    1002. 

  1002.             <p>Most problems that get reported to The Apache Group
    1003. 

  1003.             are recorded in the <a
    1004. 

  1004.             href="http://bugs.apache.org/">bug database</a>.
    1005. 

  1005.             <em><strong>Please</strong> check the existing reports,
    1006. 

  1006.             open <strong>and</strong> closed, before adding
    1007. 

  1007.             one.</em> If you find that your issue has already been
    1008. 

  1008.             reported, please <em>don't</em> add a "me, too" report.
    1009. 

  1009.             If the original report isn't closed yet, we suggest
    1010. 

  1010.             that you check it periodically. You might also consider
    1011. 

  1011.             contacting the original submitter, because there may be
    1012. 

  1012.             an email exchange going on about the issue that isn't
    1013. 

  1013.             getting recorded in the database.</p>
    1014. 

  1014.           </li>
    1015. 

    1016. 

  1016.           <li>
    1017. 

  1017.             <strong>Ask in a user support group.</strong> 
    1018. 

    1019. 

  1019.             <p>A lot of common problems never make it to the bug
    1020. 

  1020.             database because there's already high Q&amp;A traffic
    1021. 

  1021.             about them in the <a
    1022. 

  1022.             href="http://httpd.apache.org/userslist.html">Users
    1023. 

  1023.             mailing list</a> or <a
    1024. 

  1024.             href="news:comp.infosystems.www.servers.unix"><samp>comp.infosystems.www.servers.unix</samp></a>
    1025. 

  1025.             and related newsgroups. These newsgroups are also
    1026. 

  1026.             available via <a
    1027. 

  1027.             href="http://groups.google.com/groups?group=comp.infosystems.www.servers">
    1028. 

  1028.             Google</a>. Many Apache users, and some of the developers,
    1029. 

  1029.             can be found roaming their virtual halls, so it is suggested
    1030. 

  1030.             that you seek wisdom there. The chances are good that
    1031. 

  1031.             you'll get a faster answer there than from the bug
    1032. 

  1032.             database, even if you <em>don't</em> see your question
    1033. 

  1033.             already posted.</p>
    1034. 

  1034.           </li>
    1035. 

    1036. 

  1036.           <li>
    1037. 

  1037.             <strong>If all else fails, report the problem in the
    1038. 

  1038.             bug database</strong> 
    1039. 

    1040. 

  1040.             <p>If you've gone through those steps above that are
    1041. 

  1041.             appropriate and have obtained no relief, then please
    1042. 

  1042.             <em>do</em> let The Apache Group know about the problem
    1043. 

  1043.             by <a
    1044. 

  1044.             href="http://httpd.apache.org/bug_report.html">logging
    1045. 

  1045.             a bug report</a>.</p>
    1046. 

    1047. 

  1047.             <p>If your problem involves the server crashing and
    1048. 

  1048.             generating a core dump, please include a backtrace (if
    1049. 

  1049.             possible). As an example,</p>
    1050. 

    1051. 

  1051.             <dl>
    1052. 

  1052.               <dd><code># cd <em>ServerRoot</em><br />
    1053. 

  1053.                # dbx httpd core<br />
    1054. 

  1054.                (dbx) where</code></dd>
    1055. 

  1055.             </dl>
    1056. 

    1057. 

  1057.             <p>(Substitute the appropriate locations for your
    1058. 

  1058.             <samp>ServerRoot</samp> and your <samp>httpd</samp> and
    1059. 

  1059.             <samp>core</samp> files. You may have to use
    1060. 

  1060.             <code>gdb</code> instead of <code>dbx</code>.)</p>
    1061. 

  1061.           </li>
    1062. 

  1062.         </ol>
    1063. 

  1063.         <hr />
    1064. 

  1064.       </li>
    1065. 

    1066. 

  1066.       <li>
    1067. 

  1067.         <a id="compatible" name="compatible"><strong>How compatible
    1068. 

  1068.         is Apache with my existing NCSA 1.3 setup?</strong></a> 
    1069. 

    1070. 

  1070.         <p>Apache attempts to offer all the features and
    1071. 

  1071.         configuration options of NCSA httpd 1.3, as well as many of
    1072. 

  1072.         the additional features found in NCSA httpd 1.4 and NCSA
    1073. 

  1073.         httpd 1.5.</p>
    1074. 

    1075. 

  1075.         <p>NCSA httpd appears to be moving toward adding
    1076. 

  1076.         experimental features which are not generally required at
    1077. 

  1077.         the moment. Some of the experiments will succeed while
    1078. 

  1078.         others will inevitably be dropped. The Apache philosophy is
    1079. 

  1079.         to add what's needed as and when it is needed.</p>
    1080. 

    1081. 

  1081.         <p>Friendly interaction between Apache and NCSA developers
    1082. 

  1082.         should ensure that fundamental feature enhancements stay
    1083. 

  1083.         consistent between the two servers for the foreseeable
    1084. 

  1084.         future.</p>
    1085. 

  1085.         <hr />
    1086. 

  1086.       </li>
    1087. 

    1088. 

  1088.       <li>
    1089. 

  1089.         <a id="year2000" name="year2000"><strong>Is Apache Year
    1090. 

  1090.         2000 compliant?</strong></a> 
    1091. 

    1092. 

  1092.         <p>Yes, Apache is Year 2000 compliant.</p>
    1093. 

    1094. 

  1094.         <p>Apache internally never stores years as two digits. On
    1095. 

  1095.         the HTTP protocol level RFC1123-style addresses are
    1096. 

  1096.         generated which is the only format a HTTP/1.1-compliant
    1097. 

  1097.         server should generate. To be compatible with older
    1098. 

  1098.         applications Apache recognizes ANSI C's
    1099. 

  1099.         <code>asctime()</code> and RFC850-/RFC1036-style date
    1100. 

  1100.         formats, too. The <code>asctime()</code> format uses
    1101. 

  1101.         four-digit years, but the RFC850 and RFC1036 date formats
    1102. 

  1102.         only define a two-digit year. If Apache sees such a date
    1103. 

  1103.         with a value less than 70 it assumes that the century is
    1104. 

  1104.         <samp>20</samp> rather than <samp>19</samp>.</p>
    1105. 

    1106. 

  1106.         <p>Although Apache is Year 2000 compliant, you may still
    1107. 

  1107.         get problems if the underlying OS has problems with dates
    1108. 

  1108.         past year 2000 (<em>e.g.</em>, OS calls which accept or
    1109. 

  1109.         return year numbers). Most (UNIX) systems store dates
    1110. 

  1110.         internally as signed 32-bit integers which contain the
    1111. 

  1111.         number of seconds since 1<sup>st</sup> January 1970, so the
    1112. 

  1112.         magic boundary to worry about is the year 2038 and not
    1113. 

  1113.         2000. But modern operating systems shouldn't cause any
    1114. 

  1114.         trouble at all.</p>
    1115. 

    1116. 

  1116.         <p>Users of Apache 1.2.x should upgrade to a current
    1117. 

  1117.         version of Apache 1.3 (see <a
    1118. 

  1118.         href="../new_features_1_3.html#misc">year-2000 improvements
    1119. 

  1119.         in Apache 1.3</a> for details).</p>
    1120. 

    1121. 

  1121.         <p>The Apache HTTP Server project is an open-source
    1122. 

  1122.         software product of the Apache Software Foundation. The
    1123. 

  1123.         project and the Foundation <b>cannot</b> offer legal
    1124. 

  1124.         assurances regarding any suitability of the software for
    1125. 

  1125.         your application. There are several commercial Apache
    1126. 

  1126.         support organizations and derivative server products
    1127. 

  1127.         available that may be able to stand behind the software and
    1128. 

  1128.         provide you with any assurances you may require. You may
    1129. 

  1129.         find links to some of these vendors at <samp>&lt;<a
    1130. 

  1130.         href="http://www.apache.org/info/support.cgi">http://www.apache.org/info/support.cgi</a>&gt;</samp>.</p>
    1131. 

    1132. 

  1132.         <p>The Apache HTTP server software is distributed with the
    1133. 

  1133.         following disclaimer, found in the software license:</p>
    1134. 

  1134. <pre>
    1135. 

  1135.    THIS SOFTWARE IS PROVIDED BY THE APACHE GROUP ``AS IS'' AND ANY
    1136. 

  1136.    EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
    1137. 

  1137.    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
    1138. 

  1138.    PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE APACHE GROUP OR
    1139. 

  1139.    ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    1140. 

  1140.    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
    1141. 

  1141.    NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
    1142. 

  1142.    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
    1143. 

  1143.    HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
    1144. 

  1144.    STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
    1145. 

  1145.    ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
    1146. 

  1146.    OF THE POSSIBILITY OF SUCH DAMAGE.
    1147. 

  1147.  
    1148. 

  1148. </pre>
    1149. 

  1149.         <hr />
    1150. 

  1150.       </li>
    1151. 

    1152. 

  1152.       <li>
    1153. 

  1153.         <a id="submit_patch" name="submit_patch"><strong>How do I
    1154. 

  1154.         submit a patch to the Apache Group?</strong></a> 
    1155. 

    1156. 

  1156.         <p>The Apache Group encourages patches from outside
    1157. 

  1157.         developers. There are 2 main "types" of patches: small
    1158. 

  1158.         bugfixes and general improvements. Bugfixes should be
    1159. 

  1159.         submitting using the Apache <a
    1160. 

  1160.         href="http://httpd.apache.org/bug_report.html">bug report
    1161. 

  1161.         page</a>. Improvements, modifications, and additions should
    1162. 

  1162.         follow the instructions below.</p>
    1163. 

    1164. 

  1164.         <p>In general, the first course of action is to be a member
    1165. 

  1165.         of the <samp>dev@httpd.apache.org</samp> mailing list. This
    1166. 

  1166.         indicates to the Group that you are closely following the
    1167. 

  1167.         latest Apache developments. Your patch file should be
    1168. 

  1168.         generated using either '<code>diff&nbsp;-c</code>' or
    1169. 

  1169.         '<code>diff&nbsp;-u</code>' against the latest CVS tree. To
    1170. 

  1170.         submit your patch, send email to
    1171. 

  1171.         <samp>dev@httpd.apache.org</samp> with a
    1172. 

  1172.         <samp>Subject:</samp> line that starts with
    1173. 

  1173.         <samp>[PATCH]</samp> and includes a general description of
    1174. 

  1174.         the patch. In the body of the message, the patch should be
    1175. 

  1175.         clearly described and then included at the end of the
    1176. 

  1176.         message. If the patch-file is long, you can note a URL to
    1177. 

  1177.         the file instead of the file itself. Use of MIME
    1178. 

  1178.         enclosures/attachments should be avoided.</p>
    1179. 

    1180. 

  1180.         <p>Be prepared to respond to any questions about your
    1181. 

  1181.         patches and possibly defend your code. If your patch
    1182. 

  1182.         results in a lot of discussion, you may be asked to submit
    1183. 

  1183.         an updated patch that incorporate all changes and
    1184. 

  1184.         suggestions.</p>
    1185. 

  1185.         <hr />
    1186. 

  1186.       </li>
    1187. 

    1188. 

  1188.       <li>
    1189. 

  1189.         <a id="domination" name="domination"><strong>Why has Apache
    1190. 

  1190.         stolen my favourite site's Internet address?</strong></a> 
    1191. 

    1192. 

  1192.         <p>The simple answer is: "It hasn't." This misconception is
    1193. 

  1193.         usually caused by the site in question having migrated to
    1194. 

  1194.         the Apache Web server software, but not having migrated the
    1195. 

  1195.         site's content yet. When Apache is installed, the default
    1196. 

  1196.         page that gets installed tells the Webmaster the
    1197. 

  1197.         installation was successful. The expectation is that this
    1198. 

  1198.         default page will be replaced with the site's real content.
    1199. 

  1199.         If it doesn't, complain to the Webmaster, not to the Apache
    1200. 

  1200.         project -- we just make the software and aren't responsible
    1201. 

  1201.         for what people do (or don't do) with it.</p>
    1202. 

  1202.         <hr />
    1203. 

  1203.       </li>
    1204. 

    1205. 

  1205.       <li>
    1206. 

  1206.         <a id="apspam" name="apspam"><strong>Why am I getting spam
    1207. 

  1207.         mail from the Apache site?</strong></a> 
    1208. 

    1209. 

  1209.         <p>The short answer is: "You aren't." Usually when someone
    1210. 

  1210.         thinks the Apache site is originating spam, it's because
    1211. 

  1211.         they've traced the spam to a Web site, and the Web site
    1212. 

  1212.         says it's using Apache. See the <a
    1213. 

  1213.         href="#domination">previous FAQ entry</a> for more details
    1214. 

  1214.         on this phenomenon.</p>
    1215. 

    1216. 

  1216.         <p>No marketing spam originates from the Apache site. The
    1217. 

  1217.         only mail that comes from the site goes only to addresses
    1218. 

  1218.         that have been <em>requested</em> to receive the mail.</p>
    1219. 

  1219.         <hr />
    1220. 

  1220.       </li>
    1221. 

    1222. 

  1222.       <li>
    1223. 

  1223.         <a id="redist" name="redist"><strong>May I include the
    1224. 

  1224.         Apache software on a CD or other package I'm
    1225. 

  1225.         distributing?</strong></a> 
    1226. 

    1227. 

  1227.         <p>The detailed answer to this question can be found in the
    1228. 

  1228.         Apache license, which is included in the Apache
    1229. 

  1229.         distribution in the file <code>LICENSE</code>. You can also
    1230. 

  1230.         find it on the Web at <samp>&lt;<a
    1231. 

  1231.         href="http://www.apache.org/LICENSE.txt">http://www.apache.org/LICENSE.txt</a>&gt;</samp>.</p>
    1232. 

  1232.         <hr />
    1233. 

  1233.       </li>
    1234. 

    1235. 

  1235.       <li>
    1236. 

  1236.         <a id="zoom" name="zoom"><strong>What's the best
    1237. 

  1237.         hardware/operating system/... How do I get the most out of
    1238. 

  1238.         my Apache Web server?</strong></a> 
    1239. 

    1240. 

  1240.         <p>Check out Dean Gaudet's <a
    1241. 

  1241.         href="perf-tuning.html">performance tuning page</a>.</p>
    1242. 

  1242.         <hr />
    1243. 

  1243.       </li>
    1244. 

    1245. 

  1245.       <li>
    1246. 

  1246.         <a id="regex" name="regex"><strong>What are "regular
    1247. 

  1247.         expressions"?</strong></a> 
    1248. 

    1249. 

  1249.         <p>Regular expressions are a way of describing a pattern -
    1250. 

  1250.         for example, "all the words that begin with the letter A"
    1251. 

  1251.         or "every 10-digit phone number" or even "Every sentence
    1252. 

  1252.         with two commas in it, and no capital letter Q". Regular
    1253. 

  1253.         expressions (aka "regex"s) are useful in Apache because
    1254. 

  1254.         they let you apply certain attributes against collections
    1255. 

  1255.         of files or resources in very flexible ways - for example,
    1256. 

  1256.         all .gif and .jpg files under any "images" directory could
    1257. 

  1257.         be written as /\/images\/.*(jpg|gif)$/.</p>
    1258. 

    1259. 

  1259.         <p>The best overview around is probably the one which comes
    1260. 

  1260.         with Perl. We implement a simple subset of Perl's regex
    1261. 

  1261.         support, but it's still a good way to learn what they mean.
    1262. 

  1262.         You can start by going to the <a
    1263. 

  1263.         href="http://www.perl.com/CPAN-local/doc/manual/html/pod/perlre.html#Regular_Expressions">
    1264. 

  1264.         CPAN page on regular expressions</a>, and branching out
    1265. 

  1265.         from there.</p>
    1266. 

  1266.         <hr />
    1267. 

  1267.       </li>
    1268. 

    1269. 

  1269.       <li>
    1270. 

  1270.         <a id="binaries" name="binaries"><b>Why isn't there a
    1271. 

  1271.         binary for my platform?</b></a> 
    1272. 

    1273. 

  1273.         <p>The developers make sure that the software builds and
    1274. 

  1274.         works correctly on the platforms available to them; this
    1275. 

  1275.         does <i>not</i> necessarily mean that <i>your</i> platform
    1276. 

  1276.         is one of them. In addition, the Apache HTTP server project
    1277. 

  1277.         is primarily source oriented, meaning that distributing
    1278. 

  1278.         valid and buildable source code is the purpose of a
    1279. 

  1279.         release, not making sure that there is a binary package for
    1280. 

  1280.         all of the supported platforms.</p>
    1281. 

    1282. 

  1282.         <p>If you don't see a kit for your platform listed in the
    1283. 

  1283.         binary distribution area (&lt;URL:<a
    1284. 

  1284.         href="http://httpd.apache.org/dist/httpd/binaries/">http://httpd.apache.org/dist/httpd/binaries/</a>&gt;),
    1285. 

  1285.         it means either that the platform isn't available to any of
    1286. 

  1286.         the developers, or that they just haven't gotten around to
    1287. 

  1287.         preparing a binary for it. As this is a voluntary project,
    1288. 

  1288.         they are under no obligation to do so. Users are encouraged
    1289. 

  1289.         and expected to build the software themselves.</p>
    1290. 

    1291. 

  1291.         <p>The sole exception to these practices is the Windows
    1292. 

  1292.         package. Unlike most Unix and Unix-like platforms, Windows
    1293. 

  1293.         systems do not come with a bundled software development
    1294. 

  1294.         environment, so we <i>do</i> prepare binary kits for
    1295. 

  1295.         Windows when we make a release. Again, however, it's a
    1296. 

  1296.         voluntary thing and only a limited number of the developers
    1297. 

  1297.         have the capability to build the InstallShield package, so
    1298. 

  1298.         the Windows release may lag somewhat behind the source
    1299. 

  1299.         release. This lag should be no more than a few days at
    1300. 

  1300.         most.</p>
    1301. 

  1301.         <hr />
    1302. 

  1302.       </li>
    1303. 

  1303.     </ol>
    1304. 

  1304.     
    1305. 

  1305.     
    1306. 

  1306.   </body>
    1307. 

  1307. </html>
    1308. 

    1309. 

    1310. 

  1310.     
    1311. 

    1312. 

    1313. 

    1314. 

    1315. 

    1316. 

    1317. 

    1318. 

    1319. 

  1319.       
    1320. 

  1320.       
    1321. 

  1321.     
    1322. 

    1323. 

  1323.     <h3>C. Building Apache</h3>
    1324. 

    1325. 

  1325.     <ol>
    1326. 

  1326.       <li>
    1327. 

  1327.         <a id="bind8.1" name="bind8.1"><strong>Why do I get an
    1328. 

  1328.         error about an undefined reference to
    1329. 

  1329.         "<samp>__inet_ntoa</samp>" or other <samp>__inet_*</samp>
    1330. 

  1330.         symbols?</strong></a> 
    1331. 

    1332. 

  1332.         <p>If you have installed <a
    1333. 

  1333.         href="http://www.isc.org/bind.html">BIND-8</a> then this is
    1334. 

  1334.         normally due to a conflict between your include files and
    1335. 

  1335.         your libraries. BIND-8 installs its include files and
    1336. 

  1336.         libraries <code>/usr/local/include/</code> and
    1337. 

  1337.         <code>/usr/local/lib/</code>, while the resolver that comes
    1338. 

  1338.         with your system is probably installed in
    1339. 

  1339.         <code>/usr/include/</code> and <code>/usr/lib/</code>. If
    1340. 

  1340.         your system uses the header files in
    1341. 

  1341.         <code>/usr/local/include/</code> before those in
    1342. 

  1342.         <code>/usr/include/</code> but you do not use the new
    1343. 

  1343.         resolver library, then the two versions will conflict.</p>
    1344. 

    1345. 

  1345.         <p>To resolve this, you can either make sure you use the
    1346. 

  1346.         include files and libraries that came with your system or
    1347. 

  1347.         make sure to use the new include files and libraries.
    1348. 

  1348.         Adding <code>-lbind</code> to the
    1349. 

  1349.         <code>EXTRA_LDFLAGS</code> line in your
    1350. 

  1350.         <samp>Configuration</samp> file, then re-running
    1351. 

  1351.         <samp>Configure</samp>, should resolve the problem. (Apache
    1352. 

  1352.         versions 1.2.* and earlier use <code>EXTRA_LFLAGS</code>
    1353. 

  1353.         instead.)</p>
    1354. 

    1355. 

  1355.         <p><strong>Note:</strong>As of BIND 8.1.1, the bind
    1356. 

  1356.         libraries and files are installed under
    1357. 

  1357.         <samp>/usr/local/bind</samp> by default, so you should not
    1358. 

  1358.         run into this problem. Should you want to use the bind
    1359. 

  1359.         resolvers you'll have to add the following to the
    1360. 

  1360.         respective lines:</p>
    1361. 

    1362. 

  1362.         <dl>
    1363. 

  1363.           <dd><code>EXTRA_CFLAGS=-I/usr/local/bind/include<br />
    1364. 

  1364.            EXTRA_LDFLAGS=-L/usr/local/bind/lib<br />
    1365. 

  1365.            EXTRA_LIBS=-lbind</code></dd>
    1366. 

  1366.         </dl>
    1367. 

  1367.         <hr />
    1368. 

  1368.       </li>
    1369. 

    1370. 

  1370.       <li>
    1371. 

  1371.         <a id="cantbuild" name="cantbuild"><strong>Why won't Apache
    1372. 

  1372.         compile with my system's <samp>cc</samp>?</strong></a> 
    1373. 

    1374. 

  1374.         <p>If the server won't compile on your system, it is
    1375. 

  1375.         probably due to one of the following causes:</p>
    1376. 

    1377. 

  1377.         <ul>
    1378. 

  1378.           <li><strong>The <samp>Configure</samp> script doesn't
    1379. 

  1379.           recognize your system environment.</strong><br />
    1380. 

  1380.            This might be either because it's completely unknown or
    1381. 

  1381.           because the specific environment (include files, OS
    1382. 

  1382.           version, <em>et cetera</em>) isn't explicitly handled. If
    1383. 

  1383.           this happens, you may need to port the server to your OS
    1384. 

  1384.           yourself.</li>
    1385. 

    1386. 

  1386.           <li><strong>Your system's C compiler is
    1387. 

  1387.           garbage.</strong><br />
    1388. 

  1388.            Some operating systems include a default C compiler that
    1389. 

  1389.           is either not ANSI C-compliant or suffers from other
    1390. 

  1390.           deficiencies. The usual recommendation in cases like this
    1391. 

  1391.           is to acquire, install, and use <samp>gcc</samp>.</li>
    1392. 

    1393. 

  1393.           <li><strong>Your <samp>include</samp> files may be
    1394. 

  1394.           confused.</strong><br />
    1395. 

  1395.            In some cases, we have found that a compiler
    1396. 

  1396.           installation or system upgrade has left the C header
    1397. 

  1397.           files in an inconsistent state. Make sure that your
    1398. 

  1398.           include directory tree is in sync with the compiler and
    1399. 

  1399.           the operating system.</li>
    1400. 

    1401. 

  1401.           <li><strong>Your operating system or compiler may be out
    1402. 

  1402.           of revision.</strong><br />
    1403. 

  1403.            Software vendors (including those that develop operating
    1404. 

  1404.           systems) issue new releases for a reason; sometimes to
    1405. 

  1405.           add functionality, but more often to fix bugs that have
    1406. 

  1406.           been discovered. Try upgrading your compiler and/or your
    1407. 

  1407.           operating system.</li>
    1408. 

  1408.         </ul>
    1409. 

    1410. 

  1410.         <p>The Apache Group tests the ability to build the server
    1411. 

  1411.         on many different platforms. Unfortunately, we can't test
    1412. 

  1412.         all of the OS platforms there are. If you have verified
    1413. 

  1413.         that none of the above issues is the cause of your problem,
    1414. 

  1414.         and it hasn't been reported before, please submit a <a
    1415. 

  1415.         href="http://httpd.apache.org/bug_report.html">problem
    1416. 

  1416.         report</a>. Be sure to include <em>complete</em> details,
    1417. 

  1417.         such as the compiler &amp; OS versions and exact error
    1418. 

  1418.         messages.</p>
    1419. 

  1419.         <hr />
    1420. 

  1420.       </li>
    1421. 

    1422. 

  1422.       <li>
    1423. 

  1423.         <a id="linuxiovec" name="linuxiovec"><strong>Why do I get
    1424. 

  1424.         complaints about redefinition of "<code>struct
    1425. 

  1425.         iovec</code>" when compiling under Linux?</strong></a> 
    1426. 

    1427. 

  1427.         <p>This is a conflict between your C library includes and
    1428. 

  1428.         your kernel includes. You need to make sure that the
    1429. 

  1429.         versions of both are matched properly. There are two
    1430. 

  1430.         workarounds, either one will solve the problem:</p>
    1431. 

    1432. 

  1432.         <ul>
    1433. 

  1433.           <li>Remove the definition of <code>struct iovec</code>
    1434. 

  1434.           from your C library includes. It is located in
    1435. 

  1435.           <code>/usr/include/sys/uio.h</code>.
    1436. 

  1436.           <strong>Or,</strong></li>
    1437. 

    1438. 

  1438.           <li>Add <code>-DNO_WRITEV</code> to the
    1439. 

  1439.           <code>EXTRA_CFLAGS</code> line in your
    1440. 

  1440.           <samp>Configuration</samp> and reconfigure/rebuild. This
    1441. 

  1441.           hurts performance and should only be used as a last
    1442. 

  1442.           resort.</li>
    1443. 

  1443.         </ul>
    1444. 

  1444.         <hr />
    1445. 

  1445.       </li>
    1446. 

    1447. 

  1447.       <li>
    1448. 

  1448.         <a id="broken-gcc" name="broken-gcc"><strong>I'm using gcc
    1449. 

  1449.         and I get some compilation errors, what is
    1450. 

  1450.         wrong?</strong></a> 
    1451. 

    1452. 

  1452.         <p>GCC parses your system header files and produces a
    1453. 

  1453.         modified subset which it uses for compiling. This behavior
    1454. 

  1454.         ties GCC tightly to the version of your operating system.
    1455. 

  1455.         So, for example, if you were running IRIX 5.3 when you
    1456. 

  1456.         built GCC and then upgrade to IRIX 6.2 later, you will have
    1457. 

  1457.         to rebuild GCC. Similarly for Solaris 2.4, 2.5, or 2.5.1
    1458. 

  1458.         when you upgrade to 2.6. Sometimes you can type "gcc -v"
    1459. 

  1459.         and it will tell you the version of the operating system it
    1460. 

  1460.         was built against.</p>
    1461. 

    1462. 

  1462.         <p>If you fail to do this, then it is very likely that
    1463. 

  1463.         Apache will fail to build. One of the most common errors is
    1464. 

  1464.         with <code>readv</code>, <code>writev</code>, or
    1465. 

  1465.         <code>uio.h</code>. This is <strong>not</strong> a bug with
    1466. 

  1466.         Apache. You will need to re-install GCC.</p>
    1467. 

  1467.         <hr />
    1468. 

  1468.       </li>
    1469. 

    1470. 

  1470.       <li>
    1471. 

  1471.         <a id="glibc-crypt" name="glibc-crypt"><strong>I'm using
    1472. 

  1472.         RedHat Linux 5.0, or some other <samp>glibc</samp>-based
    1473. 

  1473.         Linux system, and I get errors with the <code>crypt</code>
    1474. 

  1474.         function when I attempt to build Apache 1.2.</strong></a> 
    1475. 

    1476. 

  1476.         <p><samp>glibc</samp> puts the <code>crypt</code> function
    1477. 

  1477.         into a separate library. Edit your
    1478. 

  1478.         <code>src/Configuration</code> file and set this:</p>
    1479. 

    1480. 

  1480.         <dl>
    1481. 

  1481.           <dd><code>EXTRA_LIBS=-lcrypt</code></dd>
    1482. 

  1482.         </dl>
    1483. 

    1484. 

  1484.         <p>Then re-run <samp>src/Configure</samp> and re-execute
    1485. 

  1485.         the make.</p>
    1486. 

  1486.         <hr />
    1487. 

  1487.       </li>
    1488. 

  1488.     </ol>
    1489. 

  1489.     
    1490. 

  1490.     
    1491. 

  1491.   </body>
    1492. 

  1492. </html>
    1493. 

    1494. 

    1495. 

  1495.     
    1496. 

    1497. 

    1498. 

    1499. 

    1500. 

    1501. 

    1502. 

    1503. 

    1504. 

  1504.       
    1505. 

  1505.       
    1506. 

  1506.     
    1507. 

    1508. 

  1508.     <h3>D. Error Log Messages and Problems Starting Apache</h3>
    1509. 

    1510. 

  1510.     <ol>
    1511. 

  1511.       <li>
    1512. 

  1512.         <a id="setgid" name="setgid"><strong>Why do I get
    1513. 

  1513.         "<samp>setgid: Invalid argument</samp>" at
    1514. 

  1514.         startup?</strong></a> 
    1515. 

    1516. 

  1516.         <p>Your <a
    1517. 

  1517.         href="../mod/core.html#group"><samp>Group</samp></a>
    1518. 

  1518.         directive (probably in <samp>conf/httpd.conf</samp>) needs
    1519. 

  1519.         to name a group that actually exists in the
    1520. 

  1520.         <samp>/etc/group</samp> file (or your system's equivalent).
    1521. 

  1521.         This problem is also frequently seen when a negative number
    1522. 

  1522.         is used in the <code>Group</code> directive (<em>e.g.</em>,
    1523. 

  1523.         "<code>Group&nbsp;#-1</code>"). Using a group name -- not
    1524. 

  1524.         group number -- found in your system's group database
    1525. 

  1525.         should solve this problem in all cases.</p>
    1526. 

  1526.         <hr />
    1527. 

  1527.       </li>
    1528. 

    1529. 

  1529.       <li>
    1530. 

  1530.         <a id="nodelay" name="nodelay"><strong>Why am I getting
    1531. 

  1531.         "<samp>httpd: could not set socket option
    1532. 

  1532.         TCP_NODELAY</samp>" in my error log?</strong></a> 
    1533. 

    1534. 

  1534.         <p>This message almost always indicates that the client
    1535. 

  1535.         disconnected before Apache reached the point of calling
    1536. 

  1536.         <code>setsockopt()</code> for the connection. It shouldn't
    1537. 

  1537.         occur for more than about 1% of the requests your server
    1538. 

  1538.         handles, and it's advisory only in any case.</p>
    1539. 

  1539.         <hr />
    1540. 

  1540.       </li>
    1541. 

    1542. 

  1542.       <li>
    1543. 

  1543.         <a id="peerreset" name="peerreset"><strong>Why am I getting
    1544. 

  1544.         "<samp>connection reset by peer</samp>" in my error
    1545. 

  1545.         log?</strong></a> 
    1546. 

    1547. 

  1547.         <p>This is a normal message and nothing about which to be
    1548. 

  1548.         alarmed. It simply means that the client canceled the
    1549. 

  1549.         connection before it had been completely set up - such as
    1550. 

  1550.         by the end-user pressing the "Stop" button. People's
    1551. 

  1551.         patience being what it is, sites with response-time
    1552. 

  1552.         problems or slow network links may experiences this more
    1553. 

  1553.         than high-capacity ones or those with large pipes to the
    1554. 

  1554.         network.</p>
    1555. 

  1555.         <hr />
    1556. 

  1556.       </li>
    1557. 

    1558. 

  1558.       <li>
    1559. 

  1559.         <a id="wheres-the-dump" name="wheres-the-dump"><strong>The
    1560. 

  1560.         errorlog says Apache dumped core, but where's the dump
    1561. 

  1561.         file?</strong></a> 
    1562. 

    1563. 

  1563.         <p>In Apache version 1.2, the error log message about
    1564. 

  1564.         dumped core includes the directory where the dump file
    1565. 

  1565.         should be located. However, many Unixes do not allow a
    1566. 

  1566.         process that has called <code>setuid()</code> to dump core
    1567. 

  1567.         for security reasons; the typical Apache setup has the
    1568. 

  1568.         server started as root to bind to port 80, after which it
    1569. 

  1569.         changes UIDs to a non-privileged user to serve
    1570. 

  1570.         requests.</p>
    1571. 

    1572. 

  1572.         <p>Dealing with this is extremely operating
    1573. 

  1573.         system-specific, and may require rebuilding your system
    1574. 

  1574.         kernel. Consult your operating system documentation or
    1575. 

  1575.         vendor for more information about whether your system does
    1576. 

  1576.         this and how to bypass it. If there <em>is</em> a
    1577. 

  1577.         documented way of bypassing it, it is recommended that you
    1578. 

  1578.         bypass it only for the <samp>httpd</samp> server process if
    1579. 

  1579.         possible.</p>
    1580. 

    1581. 

  1581.         <p>The canonical location for Apache's core-dump files is
    1582. 

  1582.         the <a href="../mod/core.html#serverroot">ServerRoot</a>
    1583. 

  1583.         directory. As of Apache version 1.3, the location can be
    1584. 

  1584.         set <em>via</em> the <a
    1585. 

  1585.         href="../mod/core.html#coredumpdirectory"><samp>CoreDumpDirectory</samp></a>
    1586. 

  1586.         directive to a different directory. Make sure that this
    1587. 

  1587.         directory is writable by the user the server runs as (as
    1588. 

  1588.         opposed to the user the server is <em>started</em> as).</p>
    1589. 

  1589.         <hr />
    1590. 

  1590.       </li>
    1591. 

    1592. 

  1592.       <li>
    1593. 

  1593.         <a id="linux-shmget" name="linux-shmget"><strong>When I run
    1594. 

  1594.         it under Linux I get "shmget: function not found", what
    1595. 

  1595.         should I do?</strong></a> 
    1596. 

    1597. 

  1597.         <p>Your kernel has been built without SysV IPC support. You
    1598. 

  1598.         will have to rebuild the kernel with that support enabled
    1599. 

  1599.         (it's under the "General Setup" submenu). Documentation for
    1600. 

  1600.         kernel building is beyond the scope of this FAQ; you should
    1601. 

  1601.         consult the <a
    1602. 

  1602.         href="http://www.redhat.com/mirrors/LDP/HOWTO/Kernel-HOWTO.html">
    1603. 

  1603.         Kernel HOWTO</a>, or the documentation provided with your
    1604. 

  1604.         distribution, or a <a
    1605. 

  1605.         href="http://www.redhat.com/mirrors/LDP/HOWTO/META-FAQ.html">
    1606. 

  1606.         Linux newsgroup/mailing list</a>. As a last-resort
    1607. 

  1607.         workaround, you can comment out the
    1608. 

  1608.         <code>#define&nbsp;USE_SHMGET_SCOREBOARD</code> definition
    1609. 

  1609.         in the <samp>LINUX</samp> section of
    1610. 

  1610.         <samp>src/conf.h</samp> and rebuild the server (prior to
    1611. 

  1611.         1.3b4, simply removing
    1612. 

  1612.         <code>#define&nbsp;HAVE_SHMGET</code> would have sufficed).
    1613. 

  1613.         This will produce a server which is slower and less
    1614. 

  1614.         reliable.</p>
    1615. 

  1615.         <hr />
    1616. 

  1616.       </li>
    1617. 

    1618. 

  1618.       <li>
    1619. 

  1619.         <a id="nfslocking" name="nfslocking"><strong>Server hangs,
    1620. 

  1620.         or fails to start, and/or error log fills with
    1621. 

  1621.         "<samp>fcntl: F_SETLKW: No record locks available</samp>"
    1622. 

  1622.         or similar messages</strong></a> 
    1623. 

    1624. 

  1624.         <p>These are symptoms of a fine locking problem, which
    1625. 

  1625.         usually means that the server is trying to use a
    1626. 

  1626.         synchronization file on an NFS filesystem.</p>
    1627. 

    1628. 

  1628.         <p>Because of its parallel-operation model, the Apache Web
    1629. 

  1629.         server needs to provide some form of synchronization when
    1630. 

  1630.         accessing certain resources. One of these synchronization
    1631. 

  1631.         methods involves taking out locks on a file, which means
    1632. 

  1632.         that the filesystem whereon the lockfile resides must
    1633. 

  1633.         support locking. In many cases this means it <em>can't</em>
    1634. 

  1634.         be kept on an NFS-mounted filesystem.</p>
    1635. 

    1636. 

  1636.         <p>To cause the Web server to work around the NFS locking
    1637. 

  1637.         limitations, include a line such as the following in your
    1638. 

  1638.         server configuration files:</p>
    1639. 

    1640. 

  1640.         <dl>
    1641. 

  1641.           <dd><code>LockFile /var/run/apache-lock</code></dd>
    1642. 

  1642.         </dl>
    1643. 

    1644. 

  1644.         <p>The directory should not be generally writable
    1645. 

  1645.         (<em>e.g.</em>, don't use <samp>/var/tmp</samp>). See the
    1646. 

  1646.         <a
    1647. 

  1647.         href="../mod/core.html#lockfile"><samp>LockFile</samp></a>
    1648. 

  1648.         documentation for more information.</p>
    1649. 

  1649.         <hr />
    1650. 

  1650.       </li>
    1651. 

    1652. 

  1652.       <li>
    1653. 

  1653.         <a id="aixccbug" name="aixccbug"><strong>Why am I getting
    1654. 

  1654.         "<samp>Expected &lt;/Directory&gt; but saw
    1655. 

  1655.         &lt;/Directory&gt;</samp>" when I try to start
    1656. 

  1656.         Apache?</strong></a> 
    1657. 

    1658. 

  1658.         <p>This is a known problem with certain versions of the AIX
    1659. 

  1659.         C compiler. IBM are working on a solution, and the issue is
    1660. 

  1660.         being tracked by <a
    1661. 

  1661.         href="http://bugs.apache.org/index/full/2312">problem
    1662. 

  1662.         report #2312</a>.</p>
    1663. 

  1663.         <hr />
    1664. 

  1664.       </li>
    1665. 

    1666. 

  1666.       <li>
    1667. 

  1667.         <a id="redhat" name="redhat"><strong>I'm using RedHat Linux
    1668. 

  1668.         and I have problems with httpd dying randomly or not
    1669. 

  1669.         restarting properly</strong></a> 
    1670. 

    1671. 

  1671.         <p>RedHat Linux versions 4.x (and possibly earlier) RPMs
    1672. 

  1672.         contain various nasty scripts which do not stop or restart
    1673. 

  1673.         Apache properly. These can affect you even if you're not
    1674. 

  1674.         running the RedHat supplied RPMs.</p>
    1675. 

    1676. 

  1676.         <p>If you're using the default install then you're probably
    1677. 

  1677.         running Apache 1.1.3, which is outdated. From RedHat's ftp
    1678. 

  1678.         site you can pick up a more recent RPM for Apache 1.2.x.
    1679. 

  1679.         This will solve one of the problems.</p>
    1680. 

    1681. 

  1681.         <p>If you're using a custom built Apache rather than the
    1682. 

  1682.         RedHat RPMs then you should <code>rpm -e apache</code>. In
    1683. 

  1683.         particular you want the mildly broken
    1684. 

  1684.         <code>/etc/logrotate.d/apache</code> script to be removed,
    1685. 

  1685.         and you want the broken <code>/etc/rc.d/init.d/httpd</code>
    1686. 

  1686.         (or <code>httpd.init</code>) script to be removed. The
    1687. 

  1687.         latter is actually fixed by the apache-1.2.5 RPMs but if
    1688. 

  1688.         you're building your own Apache then you probably don't
    1689. 

  1689.         want the RedHat files.</p>
    1690. 

    1691. 

  1691.         <p>We can't stress enough how important it is for folks,
    1692. 

  1692.         <em>especially vendors</em> to follow the <a
    1693. 

  1693.         href="../stopping.html">stopping Apache directions</a>
    1694. 

  1694.         given in our documentation. In RedHat's defense, the broken
    1695. 

  1695.         scripts were necessary with Apache 1.1.x because the Linux
    1696. 

  1696.         support in 1.1.x was very poor, and there were various race
    1697. 

  1697.         conditions on all platforms. None of this should be
    1698. 

  1698.         necessary with Apache 1.2 and later.</p>
    1699. 

  1699.         <hr />
    1700. 

  1700.       </li>
    1701. 

    1702. 

  1702.       <li>
    1703. 

  1703.         <a id="stopping" name="stopping"><strong>I upgraded from an
    1704. 

  1704.         Apache version earlier than 1.2.0 and suddenly I have
    1705. 

  1705.         problems with Apache dying randomly or not restarting
    1706. 

  1706.         properly</strong></a> 
    1707. 

    1708. 

  1708.         <p>You should read <a href="#redhat">the previous note</a>
    1709. 

  1709.         about problems with RedHat installations. It is entirely
    1710. 

  1710.         likely that your installation has start/stop/restart
    1711. 

  1711.         scripts which were built for an earlier version of Apache.
    1712. 

  1712.         Versions earlier than 1.2.0 had various race conditions
    1713. 

  1713.         that made it necessary to use <code>kill -9</code> at times
    1714. 

  1714.         to take out all the httpd servers. But that should not be
    1715. 

  1715.         necessary any longer. You should follow the <a
    1716. 

  1716.         href="../stopping.html">directions on how to stop and
    1717. 

  1717.         restart Apache</a>.</p>
    1718. 

    1719. 

  1719.         <p>As of Apache 1.3 there is a script
    1720. 

  1720.         <code>src/support/apachectl</code> which, after a bit of
    1721. 

  1721.         customization, is suitable for starting, stopping, and
    1722. 

  1722.         restarting your server.</p>
    1723. 

  1723.         <hr />
    1724. 

  1724.       </li>
    1725. 

    1726. 

  1726.       <li>
    1727. 

  1727.         <a id="setservername" name="setservername"><b>When I try to
    1728. 

  1728.         start Apache from a DOS window, I get a message like
    1729. 

  1729.         "<samp>Cannot determine host name. Use ServerName directive
    1730. 

  1730.         to set it manually.</samp>" What does this mean?</b></a> 
    1731. 

    1732. 

  1732.         <p>It means what it says; the Apache software can't
    1733. 

  1733.         determine the hostname of your system. Edit your
    1734. 

  1734.         <samp>conf\httpd.conf</samp> file, look for the string
    1735. 

  1735.         "ServerName", and make sure there's an uncommented
    1736. 

  1736.         directive such as</p>
    1737. 

    1738. 

  1738.         <dl>
    1739. 

  1739.           <dd><code>ServerName localhost</code></dd>
    1740. 

  1740.         </dl>
    1741. 

    1742. 

  1742.         <p>or</p>
    1743. 

    1744. 

  1744.         <dl>
    1745. 

  1745.           <dd><code>ServerName www.foo.com</code></dd>
    1746. 

  1746.         </dl>
    1747. 

    1748. 

  1748.         <p>in the file. Correct it if there one there with wrong
    1749. 

  1749.         information, or add one if you don't already have one.</p>
    1750. 

    1751. 

  1751.         <p>Also, make sure that your Windows system has DNS
    1752. 

  1752.         enabled. See the TCP/IP setup component of the Networking
    1753. 

  1753.         or Internet Options control panel.</p>
    1754. 

    1755. 

  1755.         <p>After verifying that DNS is enabled and that you have a
    1756. 

  1756.         valid hostname in your <samp>ServerName</samp> directive,
    1757. 

  1757.         try to start the server again.</p>
    1758. 

  1758.         <hr />
    1759. 

  1759.       </li>
    1760. 

    1761. 

  1761.       <li>
    1762. 

  1762.         <a id="ws2_32dll" name="ws2_32dll"><b>When I try to start
    1763. 

  1763.         Apache for Windows, I get a message like "<samp>Unable To
    1764. 

  1764.         Locate WS2_32.DLL...</samp>". What should I do?</b></a> 
    1765. 

    1766. 

  1766.         <p>Short answer: You need to install Winsock 2, available
    1767. 

  1767.         from <a
    1768. 

  1768.         href="http://www.microsoft.com/windows95/downloads/">http://www.microsoft.com/windows95/downloads/</a></p>
    1769. 

    1770. 

  1770.         <p>Detailed answer: Prior to version 1.3.9, Apache for
    1771. 

  1771.         Windows used Winsock 1.1. Beginning with version 1.3.9,
    1772. 

  1772.         Apache began using Winsock 2 features (specifically,
    1773. 

  1773.         WSADuplicateSocket()). WS2_32.DLL implements the Winsock 2
    1774. 

  1774.         API. Winsock 2 ships with Windows NT 4.0 and Windows 98.
    1775. 

  1775.         Some of the earlier releases of Windows 95 did not include
    1776. 

  1776.         Winsock 2.</p>
    1777. 

  1777.         <hr />
    1778. 

  1778.       </li>
    1779. 

    1780. 

  1780.       <li>
    1781. 

  1781.         <a id="WSADuplicateSocket"
    1782. 

  1782.         name="WSADuplicateSocket"><b>Apache for Windows does not
    1783. 

  1783.         start. Error log contains this message: "<samp>[crit]
    1784. 

  1784.         (10045) The attempted operation is not supported for the
    1785. 

  1785.         type of object referenced: Parent: WSADuplicateSocket
    1786. 

  1786.         failed for socket ###</samp>". What does this mean?</b></a>
    1787. 

  1787.         
    1788. 

    1789. 

  1789.         <p>We have seen this problem when Apache is run on systems
    1790. 

  1790.         along with Virtual Private Networking clients like Aventail
    1791. 

  1791.         Connect. Aventail Connect is a Layered Service Provider
    1792. 

  1792.         (LSP) that inserts itself, as a "shim," between the Winsock
    1793. 

  1793.         2 API and Window's native Winsock 2 implementation. The
    1794. 

  1794.         Aventail Connect shim does not implement
    1795. 

  1795.         WSADuplicateSocket, which is the cause of the failure.</p>
    1796. 

    1797. 

  1797.         <p>The shim is not unloaded when Aventail Connect is shut
    1798. 

  1798.         down. Once observed, the problem persists until the shim is
    1799. 

  1799.         either explicitly unloaded or the machine is rebooted.
    1800. 

  1800.         Instructions for temporarily removing the Aventail Connect
    1801. 

  1801.         V3.x shim can be found here: "<a
    1802. 

  1802.         href="http://support.aventail.com/akb/article00386.html">How
    1803. 

  1803.         to Remove Aventail Connect v3.x from the LSP Order for
    1804. 

  1804.         Testing Purposes</a>."</p>
    1805. 

    1806. 

  1806.         <p>Another potential solution (not tested) is to add
    1807. 

  1807.         <code>apache.exe</code> to the Aventail "Connect Exclusion
    1808. 

  1808.         List". See this link for details: "<a
    1809. 

  1809.         href="http://support.aventail.com/akb/article00586.html">How
    1810. 

  1810.         to Add an Application to Aventail Connect's Application
    1811. 

  1811.         Exclusion List</a>."</p>
    1812. 

    1813. 

  1813.         <p>Apache is affected in a similar way by <em>any</em>
    1814. 

  1814.         firewall program that isn't correctly configured. Assure
    1815. 

  1815.         you exclude your Apache server ports (usually port 80) from
    1816. 

  1816.         the list of ports to block. Refer to your firewall
    1817. 

  1817.         program's documentation for the how-to.</p>
    1818. 

  1818.         <hr />
    1819. 

  1819.       </li>
    1820. 

    1821. 

  1821.       <li>
    1822. 

  1822.         <a id="err1067" name="err1067"><b>When I try to start
    1823. 

  1823.         Apache on Windows, I get a message like "<code>System error
    1824. 

  1824.         1067 has occurred. The process terminated
    1825. 

  1825.         unexpectedly</code>." What does this mean?</b></a> 
    1826. 

    1827. 

  1827.         <p>This message means that the Web server was unable to
    1828. 

  1828.         start correctly for one reason or another. To find out why,
    1829. 

  1829.         execute the following commands in a DOS window:</p>
    1830. 

  1830. <pre>
    1831. 

  1831.     c:
    1832. 

  1832.     cd "\Program Files\Apache Group\Apache"
    1833. 

  1833.     apache
    1834. 

  1834.  
    1835. 

  1835. </pre>
    1836. 

    1837. 

  1837.         <p>(If you don't get the prompt back, hit Control-C to
    1838. 

  1838.         cause Apache to exit.)</p>
    1839. 

    1840. 

  1840.         <p>The error you see will probably be one of those
    1841. 

  1841.         preceding this question in the FAQ.</p>
    1842. 

    1843. 

  1843.         <p>As of Apache 1.3.14, first check the Windows NT Event
    1844. 

  1844.         Log for Application errors using the Windows NT/2000 Event
    1845. 

  1845.         Viewer program. Any errors that occur prior to opening the
    1846. 

  1846.         Apache error log will be stored here, if Apache is run as a
    1847. 

  1847.         Service on NT or 2000. As with any error, also check your
    1848. 

  1848.         Apache error log.</p>
    1849. 

  1849.         <hr />
    1850. 

  1850.       </li>
    1851. 

    1852. 

  1852.       <li><a id="suseFDN" name="suseFDN"><b>On a SuSE Linux system, I try and 
    1853. 

  1853.           configure access control using basic authentication.
    1854. 

  1854. 	  Although I follow the example exactly, authentication
    1855. 

  1855. 	  fails, and an error message "<code>admin: not a valid
    1856. 

  1856. 	  FDN: ....</code>" is logged.</b></a>
    1857. 

    1858. 

  1858.           <p>
    1859. 

  1859. 	  In the SuSE distribution, additional 3rd party authentication
    1860. 

  1860. 	  modules have been added and activated by default. These modules
    1861. 

  1861. 	  interfere with the Apache standard modules and cause Basic
    1862. 

  1862. 	  authentication to fail. Our recommendation is to comment all
    1863. 

  1863. 	  those modules in <code>/etc/httpd/suse_addmodule.conf</code>
    1864. 

  1864. 	  and <code>/etc/httpd/suse_loadmodule.conf</code> which are not
    1865. 

  1865. 	  actually required for running your server.
    1866. 

  1866.           </p><hr />
    1867. 

  1867.       </li>
    1868. 

    1869. 

  1869.      <li><a id="codered" name="codered"><b>Why do I have weird entries in my
    1870. 

  1870.           logs asking for <code>default.ida</code> and
    1871. 

  1871.           <code>cmd.exe</code>?</b></a>
    1872. 

  1872.       
    1873. 

  1873.           <p>The host requesting pages from your website and creating
    1874. 

  1874.           those entries is a Windows machine running IIS that has been
    1875. 

  1875.           infected by an Internet worm such as Nimda or Code Red. You
    1876. 

  1876.           can safely ignore these error messages as they do not affect
    1877. 

  1877.           Apache.  ApacheWeek has an <a
    1878. 

  1878.           href="http://www.apacheweek.com/features/codered">article</a>
    1879. 

  1879.           with more information.</p>
    1880. 

  1880.      </li>
    1881. 

    1882. 

  1882.     </ol>
    1883. 

  1883.     
    1884. 

  1884.     
    1885. 

  1885.   </body>
    1886. 

  1886. </html>
    1887. 

    1888. 

    1889. 

  1889.     
    1890. 

    1891. 

    1892. 

    1893. 

    1894. 

    1895. 

    1896. 

    1897. 

    1898. 

  1898.       
    1899. 

  1899.       
    1900. 

  1900.     
    1901. 

    1902. 

  1902.     <h3>E. Configuration Questions</h3>
    1903. 

    1904. 

  1904.     <ol>
    1905. 

  1905.       <li>
    1906. 

  1906.         <a id="fdlim" name="fdlim"><strong>Why can't I run more
    1907. 

  1907.         than &lt;<em>n</em>&gt; virtual hosts?</strong></a> 
    1908. 

    1909. 

  1909.         <p>You are probably running into resource limitations in
    1910. 

  1910.         your operating system. The most common limitation is the
    1911. 

  1911.         <em>per</em>-process limit on <strong>file
    1912. 

  1912.         descriptors</strong>, which is almost always the cause of
    1913. 

  1913.         problems seen when adding virtual hosts. Apache often does
    1914. 

  1914.         not give an intuitive error message because it is normally
    1915. 

  1915.         some library routine (such as <code>gethostbyname()</code>)
    1916. 

  1916.         which needs file descriptors and doesn't complain
    1917. 

  1917.         intelligibly when it can't get them.</p>
    1918. 

    1919. 

  1919.         <p>Each log file requires a file descriptor, which means
    1920. 

  1920.         that if you are using separate access and error logs for
    1921. 

  1921.         each virtual host, each virtual host needs two file
    1922. 

  1922.         descriptors. Each <a
    1923. 

  1923.         href="../mod/core.html#listen"><samp>Listen</samp></a>
    1924. 

  1924.         directive also needs a file descriptor.</p>
    1925. 

    1926. 

  1926.         <p>Typical values for &lt;<em>n</em>&gt; that we've seen
    1927. 

  1927.         are in the neighborhood of 128 or 250. When the server
    1928. 

  1928.         bumps into the file descriptor limit, it may dump core with
    1929. 

  1929.         a SIGSEGV, it might just hang, or it may limp along and
    1930. 

  1930.         you'll see (possibly meaningful) errors in the error log.
    1931. 

  1931.         One common problem that occurs when you run into a file
    1932. 

  1932.         descriptor limit is that CGI scripts stop being executed
    1933. 

  1933.         properly.</p>
    1934. 

    1935. 

  1935.         <p>As to what you can do about this:</p>
    1936. 

    1937. 

  1937.         <ol>
    1938. 

  1938.           <li>Reduce the number of <a
    1939. 

  1939.           href="../mod/core.html#listen"><samp>Listen</samp></a>
    1940. 

  1940.           directives. If there are no other servers running on the
    1941. 

  1941.           machine on the same port then you normally don't need any
    1942. 

  1942.           Listen directives at all. By default Apache listens to
    1943. 

  1943.           all addresses on port 80.</li>
    1944. 

    1945. 

  1945.           <li>Reduce the number of log files. You can use <a
    1946. 

  1946.           href="../mod/mod_log_config.html"><samp>mod_log_config</samp></a>
    1947. 

  1947.           to log all requests to a single log file while including
    1948. 

  1948.           the name of the virtual host in the log file. You can
    1949. 

  1949.           then write a script to split the logfile into separate
    1950. 

  1950.           files later if necessary. Such a script is provided with
    1951. 

  1951.           the Apache 1.3 distribution in the
    1952. 

  1952.           <samp>src/support/split-logfile</samp> file.</li>
    1953. 

    1954. 

  1954.           <li>
    1955. 

  1955.             Increase the number of file descriptors available to
    1956. 

  1956.             the server (see your system's documentation on the
    1957. 

  1957.             <code>limit</code> or <code>ulimit</code> commands).
    1958. 

  1958.             For some systems, information on how to do this is
    1959. 

  1959.             available in the <a href="perf.html">performance
    1960. 

  1960.             hints</a> page. There is a specific note for <a
    1961. 

  1961.             href="#freebsd-setsize">FreeBSD</a> below. 
    1962. 

    1963. 

  1963.             <p>For Windows 95, try modifying your
    1964. 

  1964.             <samp>C:\CONFIG.SYS</samp> file to include a line
    1965. 

  1965.             like</p>
    1966. 

    1967. 

  1967.             <dl>
    1968. 

  1968.               <dd><code>FILES=300</code></dd>
    1969. 

  1969.             </dl>
    1970. 

    1971. 

  1971.             <p>Remember that you'll need to reboot your Windows 95
    1972. 

  1972.             system in order for the new value to take effect.</p>
    1973. 

  1973.           </li>
    1974. 

    1975. 

  1975.           <li>"Don't do that" - try to run with fewer virtual
    1976. 

  1976.           hosts</li>
    1977. 

    1978. 

  1978.           <li>Spread your operation across multiple server
    1979. 

  1979.           processes (using <a
    1980. 

  1980.           href="../mod/core.html#listen"><samp>Listen</samp></a>
    1981. 

  1981.           for example, but see the first point) and/or ports.</li>
    1982. 

  1982.         </ol>
    1983. 

    1984. 

  1984.         <p>Since this is an operating-system limitation, there's
    1985. 

  1985.         not much else available in the way of solutions.</p>
    1986. 

    1987. 

  1987.         <p>As of 1.2.1 we have made attempts to work around various
    1988. 

  1988.         limitations involving running with many descriptors. <a
    1989. 

  1989.         href="descriptors.html">More information is
    1990. 

  1990.         available.</a></p>
    1991. 

  1991.         <hr />
    1992. 

  1992.       </li>
    1993. 

    1994. 

  1994.       <li>
    1995. 

  1995.         <a id="freebsd-setsize" name="freebsd-setsize"><strong>Can
    1996. 

  1996.         I increase <samp>FD_SETSIZE</samp> on FreeBSD?</strong></a>
    1997. 

  1997.         
    1998. 

    1999. 

  1999.         <p>On versions of FreeBSD before 3.0, the
    2000. 

  2000.         <samp>FD_SETSIZE</samp> define defaults to 256. This means
    2001. 

  2001.         that you will have trouble usefully using more than 256
    2002. 

  2002.         file descriptors in Apache. This can be increased, but
    2003. 

  2003.         doing so can be tricky.</p>
    2004. 

    2005. 

  2005.         <p>If you are using a version prior to 2.2, you need to
    2006. 

  2006.         recompile your kernel with a larger
    2007. 

  2007.         <samp>FD_SETSIZE</samp>. This can be done by adding a line
    2008. 

  2008.         such as:</p>
    2009. 

    2010. 

  2010.         <dl>
    2011. 

  2011.           <dd><code>options FD_SETSIZE <em>nnn</em></code></dd>
    2012. 

  2012.         </dl>
    2013. 

    2014. 

  2014.         <p>to your kernel config file. Starting at version 2.2,
    2015. 

  2015.         this is no longer necessary.</p>
    2016. 

    2017. 

  2017.         <p>If you are using a version of 2.1-stable from after
    2018. 

  2018.         1997/03/10 or 2.2 or 3.0-current from before 1997/06/28,
    2019. 

  2019.         there is a limit in the resolver library that prevents it
    2020. 

  2020.         from using more file descriptors than what
    2021. 

  2021.         <samp>FD_SETSIZE</samp> is set to when libc is compiled. To
    2022. 

  2022.         increase this, you have to recompile libc with a higher
    2023. 

  2023.         <samp>FD_SETSIZE</samp>.</p>
    2024. 

    2025. 

  2025.         <p>In FreeBSD 3.0, the default <samp>FD_SETSIZE</samp> has
    2026. 

  2026.         been increased to 1024 and the above limitation in the
    2027. 

  2027.         resolver library has been removed.</p>
    2028. 

    2029. 

  2029.         <p>After you deal with the appropriate changes above, you
    2030. 

  2030.         can increase the setting of <samp>FD_SETSIZE</samp> at
    2031. 

  2031.         Apache compilation time by adding
    2032. 

  2032.         "<samp>-DFD_SETSIZE=<em>nnn</em></samp>" to the
    2033. 

  2033.         <samp>EXTRA_CFLAGS</samp> line in your
    2034. 

  2034.         <samp>Configuration</samp> file.</p>
    2035. 

  2035.         <hr />
    2036. 

  2036.       </li>
    2037. 

    2038. 

  2038.       <li>
    2039. 

  2039.         <a id="errordoc401" name="errordoc401"><strong>Why doesn't
    2040. 

  2040.         my <code>ErrorDocument 401</code> work?</strong></a> 
    2041. 

    2042. 

  2042.         <p>You need to use it with a URL in the form
    2043. 

  2043.         "<samp>/foo/bar</samp>" and not one with a method and
    2044. 

  2044.         hostname such as "<samp>http://host/foo/bar</samp>". See
    2045. 

  2045.         the <a
    2046. 

  2046.         href="../mod/core.html#errordocument"><samp>ErrorDocument</samp></a>
    2047. 

  2047.         documentation for details. This was incorrectly documented
    2048. 

  2048.         in the past.</p>
    2049. 

  2049.         <hr />
    2050. 

  2050.       </li>
    2051. 

    2052. 

  2052.       <li>
    2053. 

  2053.         <a id="cookies1" name="cookies1"><strong>Why does Apache
    2054. 

  2054.         send a cookie on every response?</strong></a> 
    2055. 

    2056. 

  2056.         <p>Apache does <em>not</em> automatically send a cookie on
    2057. 

  2057.         every response, unless you have re-compiled it with the <a
    2058. 

  2058.         href="../mod/mod_usertrack.html"><samp>mod_usertrack</samp></a>
    2059. 

  2059.         module, and specifically enabled it with the <a
    2060. 

  2060.         href="../mod/mod_usertrack.html#cookietracking"><samp>CookieTracking</samp></a>
    2061. 

  2061.         directive. This module has been in Apache since version
    2062. 

  2062.         1.2. This module may help track users, and uses cookies to
    2063. 

  2063.         do this. If you are not using the data generated by
    2064. 

  2064.         <samp>mod_usertrack</samp>, do not compile it into
    2065. 

  2065.         Apache.</p>
    2066. 

  2066.         <hr />
    2067. 

  2067.       </li>
    2068. 

    2069. 

  2069.       <li>
    2070. 

  2070.         <a id="cookies2" name="cookies2"><strong>Why don't my
    2071. 

  2071.         cookies work, I even compiled in
    2072. 

  2072.         <samp>mod_cookies</samp>?</strong></a> 
    2073. 

    2074. 

  2074.         <p>Firstly, you do <em>not</em> need to compile in
    2075. 

  2075.         <samp>mod_cookies</samp> in order for your scripts to work
    2076. 

  2076.         (see the <a href="#cookies1">previous question</a> for more
    2077. 

  2077.         about <samp>mod_cookies</samp>). Apache passes on your
    2078. 

  2078.         <samp>Set-Cookie</samp> header fine, with or without this
    2079. 

  2079.         module. If cookies do not work it will be because your
    2080. 

  2080.         script does not work properly or your browser does not use
    2081. 

  2081.         cookies or is not set-up to accept them.</p>
    2082. 

  2082.         <hr />
    2083. 

  2083.       </li>
    2084. 

    2085. 

  2085.       <li>
    2086. 

  2086.         <a id="jdk1-and-http1.1"
    2087. 

  2087.         name="jdk1-and-http1.1"><strong>Why do my Java app[let]s
    2088. 

  2088.         give me plain text when I request an URL from an Apache
    2089. 

  2089.         server?</strong></a> 
    2090. 

    2091. 

  2091.         <p>As of version 1.2, Apache is an HTTP/1.1 (HyperText
    2092. 

  2092.         Transfer Protocol version 1.1) server. This fact is
    2093. 

  2093.         reflected in the protocol version that's included in the
    2094. 

  2094.         response headers sent to a client when processing a
    2095. 

  2095.         request. Unfortunately, low-level Web access classes
    2096. 

  2096.         included in the Java Development Kit (JDK) version 1.0.2
    2097. 

  2097.         expect to see the version string "HTTP/1.0" and do not
    2098. 

  2098.         correctly interpret the "HTTP/1.1" value Apache is sending
    2099. 

  2099.         (this part of the response is a declaration of what the
    2100. 

  2100.         server can do rather than a declaration of the dialect of
    2101. 

  2101.         the response). The result is that the JDK methods do not
    2102. 

  2102.         correctly parse the headers, and include them with the
    2103. 

  2103.         document content by mistake.</p>
    2104. 

    2105. 

  2105.         <p>This is definitely a bug in the JDK 1.0.2 foundation
    2106. 

  2106.         classes from Sun, and it has been fixed in version 1.1.
    2107. 

  2107.         However, the classes in question are part of the virtual
    2108. 

  2108.         machine environment, which means they're part of the Web
    2109. 

  2109.         browser (if Java-enabled) or the Java environment on the
    2110. 

  2110.         client system - so even if you develop <em>your</em>
    2111. 

  2111.         classes with a recent JDK, the eventual users might
    2112. 

  2112.         encounter the problem. The classes involved are replaceable
    2113. 

  2113.         by vendors implementing the Java virtual machine
    2114. 

  2114.         environment, and so even those that are based upon the
    2115. 

  2115.         1.0.2 version may not have this problem.</p>
    2116. 

    2117. 

  2117.         <p>In the meantime, a workaround is to tell Apache to
    2118. 

  2118.         "fake" an HTTP/1.0 response to requests that come from the
    2119. 

  2119.         JDK methods; this can be done by including a line such as
    2120. 

  2120.         the following in your server configuration files:</p>
    2121. 

    2122. 

  2122.         <dl>
    2123. 

  2123.           <dd><code>BrowserMatch Java1.0 force-response-1.0<br />
    2124. 

  2124.            BrowserMatch JDK/1.0 force-response-1.0</code></dd>
    2125. 

  2125.         </dl>
    2126. 

    2127. 

  2127.         <p>More information about this issue can be found in the <a
    2128. 

  2128.         href="http://httpd.apache.org/info/jdk-102.html"><cite>Java
    2129. 

  2129.         and HTTP/1.1</cite></a> page at the Apache web site.</p>
    2130. 

  2130.         <hr />
    2131. 

  2131.       </li>
    2132. 

    2133. 

  2133.       <li>
    2134. 

  2134.         <a id="midi" name="midi"><strong>How do I get Apache to
    2135. 

  2135.         send a MIDI file so the browser can play it?</strong></a> 
    2136. 

    2137. 

  2137.         <p>Even though the registered MIME type for MIDI files is
    2138. 

  2138.         <samp>audio/midi</samp>, some browsers are not set up to
    2139. 

  2139.         recognize it as such; instead, they look for
    2140. 

  2140.         <samp>audio/x-midi</samp>. There are two things you can do
    2141. 

  2141.         to address this:</p>
    2142. 

    2143. 

  2143.         <ol>
    2144. 

  2144.           <li>Configure your browser to treat documents of type
    2145. 

  2145.           <samp>audio/midi</samp> correctly. This is the type that
    2146. 

  2146.           Apache sends by default. This may not be workable,
    2147. 

  2147.           however, if you have many client installations to change,
    2148. 

  2148.           or if some or many of the clients are not under your
    2149. 

  2149.           control.</li>
    2150. 

    2151. 

  2151.           <li>
    2152. 

  2152.             Instruct Apache to send a different
    2153. 

  2153.             <samp>Content-type</samp> header for these files by
    2154. 

  2154.             adding the following line to your server's
    2155. 

  2155.             configuration files: 
    2156. 

    2157. 

  2157.             <dl>
    2158. 

  2158.               <dd><code>AddType audio/x-midi .mid .midi
    2159. 

  2159.               .kar</code></dd>
    2160. 

  2160.             </dl>
    2161. 

    2162. 

  2162.             <p>Note that this may break browsers that <em>do</em>
    2163. 

  2163.             recognize the <samp>audio/midi</samp> MIME type unless
    2164. 

  2164.             they're prepared to also handle
    2165. 

  2165.             <samp>audio/x-midi</samp> the same way.</p>
    2166. 

  2166.           </li>
    2167. 

  2167.         </ol>
    2168. 

  2168.         <hr />
    2169. 

  2169.       </li>
    2170. 

    2171. 

  2171.       <li>
    2172. 

  2172.         <a id="addlog" name="addlog"><strong>How do I add browsers
    2173. 

  2173.         and referrers to my logs?</strong></a> 
    2174. 

    2175. 

  2175.         <p>Apache provides a couple of different ways of doing
    2176. 

  2176.         this. The recommended method is to compile the <a
    2177. 

  2177.         href="../mod/mod_log_config.html"><samp>mod_log_config</samp></a>
    2178. 

  2178.         module into your configuration and use the <a
    2179. 

  2179.         href="../mod/mod_log_config.html#customlog"><samp>CustomLog</samp></a>
    2180. 

  2180.         directive.</p>
    2181. 

    2182. 

  2182.         <p>You can either log the additional information in files
    2183. 

  2183.         other than your normal transfer log, or you can add them to
    2184. 

  2184.         the records already being written. For example:</p>
    2185. 

    2186. 

  2186.         <p>
    2187. 

  2187.         <code>CustomLog&nbsp;logs/access_log&nbsp;"%h&nbsp;%l&nbsp;%u&nbsp;%t&nbsp;\"%r\"&nbsp;%s&nbsp;%b&nbsp;\"%{Referer}i\"&nbsp;\"%{User-Agent}i\""</code></p>
    2188. 

    2189. 

  2189.         <p>This will add the values of the <samp>User-agent:</samp>
    2190. 

  2190.         and <samp>Referer:</samp> headers, which indicate the
    2191. 

  2191.         client and the referring page, respectively, to the end of
    2192. 

  2192.         each line in the access log.</p>
    2193. 

    2194. 

  2194.         <p>You may want to check out the <cite>Apache Week</cite>
    2195. 

  2195.         article entitled: "<a
    2196. 

  2196.         href="http://www.apacheweek.com/features/logfiles"
    2197. 

  2197.         rel="Help"><cite>Gathering Visitor Information: Customizing
    2198. 

  2198.         Your Logfiles</cite></a>".</p>
    2199. 

  2199.         <hr />
    2200. 

  2200.       </li>
    2201. 

    2202. 

  2202.       <li>
    2203. 

  2203.         <a id="set-servername" name="set-servername"><strong>Why
    2204. 

  2204.         does accessing directories only work when I include the
    2205. 

  2205.         trailing "/"
    2206. 

  2206.         (<em>e.g.</em>,&nbsp;<samp>http://foo.domain.com/~user/</samp>)
    2207. 

  2207.         but not when I omit it
    2208. 

  2208.         (<em>e.g.</em>,&nbsp;<samp>http://foo.domain.com/~user</samp>)?</strong></a>
    2209. 

  2209.         
    2210. 

    2211. 

  2211.         <p>When you access a directory without a trailing "/",
    2212. 

  2212.         Apache needs to send what is called a redirect to the
    2213. 

  2213.         client to tell it to add the trailing slash. If it did not
    2214. 

  2214.         do so, relative URLs would not work properly. When it sends
    2215. 

  2215.         the redirect, it needs to know the name of the server so
    2216. 

  2216.         that it can include it in the redirect. There are two ways
    2217. 

  2217.         for Apache to find this out; either it can guess, or you
    2218. 

  2218.         can tell it. If your DNS is configured correctly, it can
    2219. 

  2219.         normally guess without any problems. If it is not, however,
    2220. 

  2220.         then you need to tell it.</p>
    2221. 

    2222. 

  2222.         <p>Add a <a
    2223. 

  2223.         href="../mod/core.html#servername">ServerName</a> directive
    2224. 

  2224.         to the config file to tell it what the domain name of the
    2225. 

  2225.         server is.</p>
    2226. 

  2226.         <hr />
    2227. 

  2227.       </li>
    2228. 

    2229. 

  2229.       <li>
    2230. 

  2230.         <a id="no-info-directives"
    2231. 

  2231.         name="no-info-directives"><strong>Why doesn't mod_info list
    2232. 

  2232.         any directives?</strong></a> 
    2233. 

    2234. 

  2234.         <p>The <a
    2235. 

  2235.         href="../mod/mod_info.html"><samp>mod_info</samp></a>
    2236. 

  2236.         module allows you to use a Web browser to see how your
    2237. 

  2237.         server is configured. Among the information it displays is
    2238. 

  2238.         the list modules and their configuration directives. The
    2239. 

  2239.         "current" values for the directives are not necessarily
    2240. 

  2240.         those of the running server; they are extracted from the
    2241. 

  2241.         configuration files themselves at the time of the request.
    2242. 

  2242.         If the files have been changed since the server was last
    2243. 

  2243.         reloaded, the display will not match the values actively in
    2244. 

  2244.         use. If the files and the path to the files are not
    2245. 

  2245.         readable by the user as which the server is running (see
    2246. 

  2246.         the <a href="../mod/core.html#user"><samp>User</samp></a>
    2247. 

  2247.         directive), then <samp>mod_info</samp> cannot read them in
    2248. 

  2248.         order to list their values. An entry <em>will</em> be made
    2249. 

  2249.         in the error log in this event, however.</p>
    2250. 

  2250.         <hr />
    2251. 

  2251.       </li>
    2252. 

    2253. 

  2253.       <li>
    2254. 

  2254.         <a id="namevhost" name="namevhost"><strong>I upgraded to
    2255. 

  2255.         Apache 1.3 and now my virtual hosts don't
    2256. 

  2256.         work!</strong></a> 
    2257. 

    2258. 

  2258.         <p>In versions of Apache prior to 1.3b2, there was a lot of
    2259. 

  2259.         confusion regarding address-based virtual hosts and
    2260. 

  2260.         (HTTP/1.1) name-based virtual hosts, and the rules
    2261. 

  2261.         concerning how the server processed
    2262. 

  2262.         <samp>&lt;VirtualHost&gt;</samp> definitions were very
    2263. 

  2263.         complex and not well documented.</p>
    2264. 

    2265. 

  2265.         <p>Apache 1.3b2 introduced a new directive, <a
    2266. 

  2266.         href="../mod/core.html#namevirtualhost"><samp>NameVirtualHost</samp></a>,
    2267. 

  2267.         which simplifies the rules quite a bit. However, changing
    2268. 

  2268.         the rules like this means that your existing name-based
    2269. 

  2269.         <samp>&lt;VirtualHost&gt;</samp> containers probably won't
    2270. 

  2270.         work correctly immediately following the upgrade.</p>
    2271. 

    2272. 

  2272.         <p>To correct this problem, add the following line to the
    2273. 

  2273.         beginning of your server configuration file, before
    2274. 

  2274.         defining any virtual hosts:</p>
    2275. 

    2276. 

  2276.         <dl>
    2277. 

  2277.           <dd><code>NameVirtualHost <em>n.n.n.n</em></code></dd>
    2278. 

  2278.         </dl>
    2279. 

    2280. 

  2280.         <p>Replace the "<samp>n.n.n.n</samp>" with the IP address
    2281. 

  2281.         to which the name-based virtual host names resolve; if you
    2282. 

  2282.         have multiple name-based hosts on multiple addresses,
    2283. 

  2283.         repeat the directive for each address.</p>
    2284. 

    2285. 

  2285.         <p>Make sure that your name-based
    2286. 

  2286.         <samp>&lt;VirtualHost&gt;</samp> blocks contain
    2287. 

  2287.         <samp>ServerName</samp> and possibly
    2288. 

  2288.         <samp>ServerAlias</samp> directives so Apache can be sure
    2289. 

  2289.         to tell them apart correctly.</p>
    2290. 

    2291. 

  2291.         <p>Please see the <a href="../vhosts/">Apache Virtual Host
    2292. 

  2292.         documentation</a> for further details about
    2293. 

  2293.         configuration.</p>
    2294. 

  2294.         <hr />
    2295. 

  2295.       </li>
    2296. 

    2297. 

  2297.       <li>
    2298. 

  2298.         <a id="redhat-htm" name="redhat-htm"><strong>I'm using
    2299. 

  2299.         RedHat Linux and my .htm files are showing up as HTML
    2300. 

  2300.         source rather than being formatted!</strong></a> 
    2301. 

    2302. 

  2302.         <p>RedHat messed up and forgot to put a content type for
    2303. 

  2303.         <code>.htm</code> files into <code>/etc/mime.types</code>.
    2304. 

  2304.         Edit <code>/etc/mime.types</code>, find the line containing
    2305. 

  2305.         <code>html</code> and add <code>htm</code> to it. Then
    2306. 

  2306.         restart your httpd server:</p>
    2307. 

    2308. 

  2308.         <dl>
    2309. 

  2309.           <dd><code>kill -HUP `cat /var/run/httpd.pid`</code></dd>
    2310. 

  2310.         </dl>
    2311. 

    2312. 

  2312.         <p>Then <strong>clear your browsers' caches</strong>. (Many
    2313. 

  2313.         browsers won't re-examine the content type after they've
    2314. 

  2314.         reloaded a page.)</p>
    2315. 

  2315.         <hr />
    2316. 

  2316.       </li>
    2317. 

    2318. 

  2318.       <li>
    2319. 

  2319.         <a id="htaccess-work" name="htaccess-work"><strong>My
    2320. 

  2320.         <code>.htaccess</code> files are being
    2321. 

  2321.         ignored.</strong></a> 
    2322. 

    2323. 

  2323.         <p>This is almost always due to your <a
    2324. 

  2324.         href="../mod/core.html#allowoverride">AllowOverride</a>
    2325. 

  2325.         directive being set incorrectly for the directory in
    2326. 

  2326.         question. If it is set to <code>None</code> then .htaccess
    2327. 

  2327.         files will not even be looked for. If you do have one that
    2328. 

  2328.         is set, then be certain it covers the directory you are
    2329. 

  2329.         trying to use the .htaccess file in. This is normally
    2330. 

  2330.         accomplished by ensuring it is inside the proper <a
    2331. 

  2331.         href="../mod/core.html#directory">Directory</a>
    2332. 

  2332.         container.</p>
    2333. 

  2333.         <hr />
    2334. 

  2334.       </li>
    2335. 

    2336. 

  2336.       <li>
    2337. 

  2337.         <a id="forbidden" name="forbidden"><strong>Why do I get a
    2338. 

  2338.         "<samp>Forbidden</samp>" message whenever I try to access a
    2339. 

  2339.         particular directory?</strong></a> 
    2340. 

    2341. 

  2341.         <p>This message is generally caused because either</p>
    2342. 

    2343. 

  2343.         <ul>
    2344. 

  2344.           <li>The underlying file system permissions do not allow
    2345. 

  2345.           the User/Group under which Apache is running to access
    2346. 

  2346.           the necessary files; or</li>
    2347. 

    2348. 

  2348.           <li>The Apache configuration has some access restrictions
    2349. 

  2349.           in place which forbid access to the files.</li>
    2350. 

  2350.         </ul>
    2351. 

    2352. 

  2352.         <p>You can determine which case applies to your situation
    2353. 

  2353.         by checking the error log.</p>
    2354. 

    2355. 

  2355.         <p>In the case where file system permission are at fault,
    2356. 

  2356.         remember that not only must the directory and files in
    2357. 

  2357.         question be readable, but also all parent directories must
    2358. 

  2358.         be at least searchable by the web server in order for the
    2359. 

  2359.         content to be accessible.</p>
    2360. 

  2360.         <hr />
    2361. 

  2361.       </li>
    2362. 

    2363. 

  2363.       <li>
    2364. 

  2364.         <a id="malfiles" name="malfiles"><b>Why do I get a
    2365. 

  2365.         "<samp>Forbidden/You don't have permission to access / on
    2366. 

  2366.         this server</samp>" message whenever I try to access my
    2367. 

  2367.         server?</b></a> 
    2368. 

    2369. 

  2369.         <p>Search your <code>conf/httpd.conf</code> file for this
    2370. 

  2370.         exact string: <code>&lt;Files ~&gt;</code>. If you find it,
    2371. 

  2371.         that's your problem -- that particular &lt;Files&gt;
    2372. 

  2372.         container is malformed. Delete it or replace it with
    2373. 

  2373.         <code>&lt;Files ~ "^\.ht"&gt;</code> and restart your
    2374. 

  2374.         server and things should work as expected.</p>
    2375. 

    2376. 

  2376.         <p>This error appears to be caused by a problem with the
    2377. 

  2377.         version of linuxconf distributed with Redhat 6.x. It may
    2378. 

  2378.         reappear if you use linuxconf again.</p>
    2379. 

    2380. 

  2380.         <p>If you don't find this string, check out the <a
    2381. 

  2381.         href="#forbidden">previous question</a>.</p>
    2382. 

  2382.         <hr />
    2383. 

  2383.       </li>
    2384. 

    2385. 

  2385.       <li>
    2386. 

  2386.         <a id="ie-ignores-mime" name="ie-ignores-mime"><strong>Why
    2387. 

  2387.         do my files appear correctly in Internet Explorer, but show
    2388. 

  2388.         up as source or trigger a save window with
    2389. 

  2389.         Netscape?</strong></a> 
    2390. 

    2391. 

  2391.         <p>Internet Explorer (IE) and Netscape handle mime type
    2392. 

  2392.         detection in different ways, and therefore will display the
    2393. 

  2393.         document differently. In particular, IE sometimes relies on
    2394. 

  2394.         the file extension to determine the mime type. This can
    2395. 

  2395.         happen when the server specifies a mime type of
    2396. 

  2396.         <code>application/octet-stream</code> or
    2397. 

  2397.         <code>text/plain</code>. (Unfortunately, this behavior
    2398. 

  2398.         makes it impossible to properly send plain text in some
    2399. 

  2399.         situations unless the file extension is <code>txt</code>.)
    2400. 

  2400.         There are more details available on IE's mime type
    2401. 

  2401.         detection behavior in an <a
    2402. 

  2402.         href="http://msdn.microsoft.com/workshop/networking/moniker/overview/appendix_a.asp">
    2403. 

  2403.         MSDN article</a>.</p>
    2404. 

    2405. 

  2405.         <p>In order to make all browsers work correctly, you should
    2406. 

  2406.         assure that Apache sends the correct mime type for the
    2407. 

  2407.         file. This is accomplished by editing the
    2408. 

  2408.         <code>mime.types</code> file or using an <a
    2409. 

  2409.         href="../mod/mod_mime.html#addtype"><code>AddType</code></a>
    2410. 

  2410.         directive in the Apache configuration files.</p>
    2411. 

  2411.         <hr />
    2412. 

  2412.       </li>
    2413. 

  2413.       <li>
    2414. 

  2414. 	<a name="canonical-hostnames"><strong>My site is accessible
    2415. 

  2415.         under many different hostnames; how do I redirect clients
    2416. 

  2416.         so that they see only a single name?</strong></a>
    2417. 

    2418. 

  2418.         <p>Many sites map a variety of hostnames to the same content.
    2419. 

  2419.         For example, <code>www.example.com</code>,
    2420. 

  2420.         <code>example.com</code> and <code>www.example.net</code> may
    2421. 

  2421.         all refer to the same site.  It is best to make sure that,
    2422. 

  2422.         regardless of the name clients use to access the site, they
    2423. 

  2423.         will be redirected to a single, canonical hostname.  This
    2424. 

  2424.         makes the site easier to maintain and assures that there will
    2425. 

  2425.         be only one version of the site in proxy caches and search
    2426. 

  2426.         engines.</p>
    2427. 

    2428. 

  2428.         <p>There are two techniques to implement canonical hostnames:</p>
    2429. 

    2430. 

  2430.         <ol>
    2431. 

  2431.           <li>Use <a href="../mod/mod_rewrite.html">mod_rewrite</a>
    2432. 

  2432.           as described in the "Canonical Hostnames" section of the
    2433. 

  2433.           <a href="rewriteguide.html">URL Rewriting Guide</a>.</li>
    2434. 

    2435. 

  2435.           <li>Use <a href="../vhosts/name-based.html">name-based
    2436. 

  2436.           virtual hosting</a>:
    2437. 

    2438. 

  2438. <blockquote><code>
    2439. 

  2439. NameVirtualHost *<br />
    2440. 

  2440. <br />
    2441. 

  2441. &lt;VirtualHost *&gt;<br />
    2442. 

  2442. &nbsp;&nbsp;ServerName www.example.net<br />
    2443. 

  2443. &nbsp;&nbsp;ServerAlias example.com<br />
    2444. 

  2444. &nbsp;&nbsp;Redirect permanent / http://www.example.com/<br />
    2445. 

  2445. &lt;/VirtualHost&gt;<br />
    2446. 

  2446. <br />
    2447. 

  2447. &lt;VirtualHost *&gt;<br />
    2448. 

  2448. &nbsp;&nbsp;ServerName www.example.com<br />
    2449. 

  2449. &nbsp;&nbsp;DocumentRoot /usr/local/apache/htdocs<br />
    2450. 

  2450. &lt;/VirtualHost&gt;
    2451. 

  2451. </code></blockquote>
    2452. 

  2452.           </li></ol>
    2453. 

  2453.         <hr /></li>
    2454. 

    2455. 

  2455.          <li><a id="firewall" name="firewall"><strong>Why can I access my
    2456. 

  2456.          website from the server or from my local network, but I
    2457. 

  2457.          can't access it from elsewhere on the Internet?</strong></a>
    2458. 

    2459. 

  2459.          <p>There are many possible reasons for this, and almost all
    2460. 

  2460.          of them are related to the configuration of your network, not
    2461. 

  2461.          the configuration of the Apache HTTP Server.  One of the most
    2462. 

  2462.          common problems is that a firewall blocks access to the
    2463. 

  2463.          default HTTP port 80.  In particular, many consumer ISPs
    2464. 

  2464.          block access to this port.  You can see if this is the case
    2465. 

  2465.          by changing any <code>Port</code> and <code>Listen</code>
    2466. 

  2466.          directives in <code>httpd.conf</code> to use port 8000 and
    2467. 

  2467.          then request your site using
    2468. 

  2468.          <code>http://yourhost.example.com:8000/</code>.  (Of course,
    2469. 

  2469.          a very restrictive firewall may block this port as well.)</p>
    2470. 

    2471. 

  2471.         <hr /></li>
    2472. 

    2473. 

    2474. 

  2474.     </ol>
    2475. 

  2475.     
    2476. 

  2476.     
    2477. 

  2477.   </body>
    2478. 

  2478. </html>
    2479. 

    2480. 

    2481. 

  2481.     
    2482. 

    2483. 

    2484. 

    2485. 

    2486. 

    2487. 

    2488. 

    2489. 

    2490. 

  2490.       
    2491. 

  2491.       
    2492. 

  2492.     
    2493. 

    2494. 

  2494.     <h3>F. Dynamic Content (CGI and SSI)</h3>
    2495. 

    2496. 

  2496.     <ol>
    2497. 

  2497.       <li>
    2498. 

  2498.         <a id="CGIoutsideScriptAlias"
    2499. 

  2499.         name="CGIoutsideScriptAlias"><strong>How do I enable CGI
    2500. 

  2500.         execution in directories other than the
    2501. 

  2501.         ScriptAlias?</strong></a> 
    2502. 

    2503. 

  2503.         <p>Apache recognizes all files in a directory named as a <a
    2504. 

  2504.         href="../mod/mod_alias.html#scriptalias"><samp>ScriptAlias</samp></a>
    2505. 

  2505.         as being eligible for execution rather than processing as
    2506. 

  2506.         normal documents. This applies regardless of the file name,
    2507. 

  2507.         so scripts in a ScriptAlias directory don't need to be
    2508. 

  2508.         named "<samp>*.cgi</samp>" or "<samp>*.pl</samp>" or
    2509. 

  2509.         whatever. In other words, <em>all</em> files in a
    2510. 

  2510.         ScriptAlias directory are scripts, as far as Apache is
    2511. 

  2511.         concerned.</p>
    2512. 

    2513. 

  2513.         <p>To persuade Apache to execute scripts in other
    2514. 

  2514.         locations, such as in directories where normal documents
    2515. 

  2515.         may also live, you must tell it how to recognize them - and
    2516. 

  2516.         also that it's okay to execute them. For this, you need to
    2517. 

  2517.         use something like the <a
    2518. 

  2518.         href="../mod/mod_mime.html#addhandler"><samp>AddHandler</samp></a>
    2519. 

  2519.         directive.</p>
    2520. 

    2521. 

  2521.         <ol>
    2522. 

  2522.           <li>
    2523. 

  2523.             In an appropriate section of your server configuration
    2524. 

  2524.             files, add a line such as 
    2525. 

    2526. 

  2526.             <dl>
    2527. 

  2527.               <dd><code>AddHandler cgi-script .cgi</code></dd>
    2528. 

  2528.             </dl>
    2529. 

    2530. 

  2530.             <p>The server will then recognize that all files in
    2531. 

  2531.             that location (and its logical descendants) that end in
    2532. 

  2532.             "<samp>.cgi</samp>" are script files, not
    2533. 

  2533.             documents.</p>
    2534. 

  2534.           </li>
    2535. 

    2536. 

  2536.           <li>Make sure that the directory location is covered by
    2537. 

  2537.           an <a
    2538. 

  2538.           href="../mod/core.html#options"><samp>Options</samp></a>
    2539. 

  2539.           declaration that includes the <samp>ExecCGI</samp>
    2540. 

  2540.           option.</li>
    2541. 

  2541.         </ol>
    2542. 

    2543. 

  2543.         <p>In some situations, you might not want to actually allow
    2544. 

  2544.         all files named "<samp>*.cgi</samp>" to be executable.
    2545. 

  2545.         Perhaps all you want is to enable a particular file in a
    2546. 

  2546.         normal directory to be executable. This can be
    2547. 

  2547.         alternatively accomplished <em>via</em> <a
    2548. 

  2548.         href="../mod/mod_rewrite.html"><samp>mod_rewrite</samp></a>
    2549. 

  2549.         and the following steps:</p>
    2550. 

    2551. 

  2551.         <ol>
    2552. 

  2552.           <li>
    2553. 

  2553.             Locally add to the corresponding <samp>.htaccess</samp>
    2554. 

  2554.             file a ruleset similar to this one: 
    2555. 

    2556. 

  2556.             <dl>
    2557. 

  2557.               <dd><code>RewriteEngine on<br />
    2558. 

  2558.                RewriteBase /~foo/bar/<br />
    2559. 

  2559.                RewriteRule ^quux\.cgi$ -
    2560. 

  2560.               [T=application/x-httpd-cgi]</code></dd>
    2561. 

  2561.             </dl>
    2562. 

  2562.           </li>
    2563. 

    2564. 

  2564.           <li>Make sure that the directory location is covered by
    2565. 

  2565.           an <a
    2566. 

  2566.           href="../mod/core.html#options"><samp>Options</samp></a>
    2567. 

  2567.           declaration that includes the <samp>ExecCGI</samp> and
    2568. 

  2568.           <samp>FollowSymLinks</samp> option.</li>
    2569. 

  2569.         </ol>
    2570. 

  2570.         <hr />
    2571. 

  2571.       </li>
    2572. 

    2573. 

  2573.       <li>
    2574. 

  2574.         <a id="premature-script-headers"
    2575. 

  2575.         name="premature-script-headers"><strong>What does it mean
    2576. 

  2576.         when my CGIs fail with "<samp>Premature end of script
    2577. 

  2577.         headers</samp>"?</strong></a> 
    2578. 

    2579. 

  2579.         <p>It means just what it says: the server was expecting a
    2580. 

  2580.         complete set of HTTP headers (one or more followed by a
    2581. 

  2581.         blank line), and didn't get them.</p>
    2582. 

    2583. 

  2583.         <p>The most common cause of this problem is the script
    2584. 

  2584.         dying before sending the complete set of headers, or
    2585. 

  2585.         possibly any at all, to the server. To see if this is the
    2586. 

  2586.         case, try running the script standalone from an interactive
    2587. 

  2587.         session, rather than as a script under the server. If you
    2588. 

  2588.         get error messages, this is almost certainly the cause of
    2589. 

  2589.         the "premature end of script headers" message. Even if the
    2590. 

  2590.         CGI runs fine from the command line, remember that the
    2591. 

  2591.         environment and permissions may be different when running
    2592. 

  2592.         under the web server. The CGI can only access resources
    2593. 

  2593.         allowed for the <a
    2594. 

  2594.         href="../mod/core.html#user"><code>User</code></a> and <a
    2595. 

  2595.         href="../mod/core.html#group"><code>Group</code></a>
    2596. 

  2596.         specified in your Apache configuration. In addition, the
    2597. 

  2597.         environment will not be the same as the one provided on the
    2598. 

  2598.         command line, but it can be adjusted using the directives
    2599. 

  2599.         provided by <a href="../mod/mod_env.html">mod_env</a>.</p>
    2600. 

    2601. 

  2601.         <p>The second most common cause of this (aside from people
    2602. 

  2602.         not outputting the required headers at all) is a result of
    2603. 

  2603.         an interaction with Perl's output buffering. To make Perl
    2604. 

  2604.         flush its buffers after each output statement, insert the
    2605. 

  2605.         following statements around the <code>print</code> or
    2606. 

  2606.         <code>write</code> statements that send your HTTP
    2607. 

  2607.         headers:</p>
    2608. 

    2609. 

  2609.         <dl>
    2610. 

  2610.           <dd><code>{<br />
    2611. 

  2611.            &nbsp;local ($oldbar) = $|;<br />
    2612. 

  2612.            &nbsp;$cfh = select (STDOUT);<br />
    2613. 

  2613.            &nbsp;$| = 1;<br />
    2614. 

  2614.            &nbsp;#<br />
    2615. 

  2615.            &nbsp;# print your HTTP headers here<br />
    2616. 

  2616.            &nbsp;#<br />
    2617. 

  2617.            &nbsp;$| = $oldbar;<br />
    2618. 

  2618.            &nbsp;select ($cfh);<br />
    2619. 

  2619.            }</code></dd>
    2620. 

  2620.         </dl>
    2621. 

    2622. 

  2622.         <p>This is generally only necessary when you are calling
    2623. 

  2623.         external programs from your script that send output to
    2624. 

  2624.         stdout, or if there will be a long delay between the time
    2625. 

  2625.         the headers are sent and the actual content starts being
    2626. 

  2626.         emitted. To maximize performance, you should turn
    2627. 

  2627.         buffer-flushing back <em>off</em> (with <code>$| = 0</code>
    2628. 

  2628.         or the equivalent) after the statements that send the
    2629. 

  2629.         headers, as displayed above.</p>
    2630. 

    2631. 

  2631.         <p>If your script isn't written in Perl, do the equivalent
    2632. 

  2632.         thing for whatever language you <em>are</em> using
    2633. 

  2633.         (<em>e.g.</em>, for C, call <code>fflush()</code> after
    2634. 

  2634.         writing the headers).</p>
    2635. 

    2636. 

  2636.         <p>Another cause for the "premature end of script headers"
    2637. 

  2637.         message are the RLimitCPU and RLimitMEM directives. You may
    2638. 

  2638.         get the message if the CGI script was killed due to a
    2639. 

  2639.         resource limit.</p>
    2640. 

    2641. 

  2641.         <p>In addition, a configuration problem in <a
    2642. 

  2642.         href="../suexec.html">suEXEC</a>, mod_perl, or another
    2643. 

  2643.         third party module can often interfere with the execution
    2644. 

  2644.         of your CGI and cause the "premature end of script headers"
    2645. 

  2645.         message.</p>
    2646. 

  2646.         <hr />
    2647. 

  2647.       </li>
    2648. 

    2649. 

  2649.       <li>
    2650. 

  2650.         <a id="POSTnotallowed" name="POSTnotallowed"><strong>Why do
    2651. 

  2651.         I keep getting "Method Not Allowed" for form POST
    2652. 

  2652.         requests?</strong></a> 
    2653. 

    2654. 

  2654.         <p>This is almost always due to Apache not being configured
    2655. 

  2655.         to treat the file you are trying to POST to as a CGI
    2656. 

  2656.         script. You can not POST to a normal HTML file; the
    2657. 

  2657.         operation has no meaning. See the FAQ entry on <a
    2658. 

  2658.         href="#CGIoutsideScriptAlias">CGIs outside ScriptAliased
    2659. 

  2659.         directories</a> for details on how to configure Apache to
    2660. 

  2660.         treat the file in question as a CGI.</p>
    2661. 

  2661.         <hr />
    2662. 

  2662.       </li>
    2663. 

    2664. 

  2664.       <li>
    2665. 

  2665.         <a id="nph-scripts" name="nph-scripts"><strong>How can I
    2666. 

  2666.         get my script's output without Apache buffering it? Why
    2667. 

  2667.         doesn't my server push work?</strong></a> 
    2668. 

    2669. 

  2669.         <p>As of Apache 1.3, CGI scripts are essentially not
    2670. 

  2670.         buffered. Every time your script does a "flush" to output
    2671. 

  2671.         data, that data gets relayed on to the client. Some
    2672. 

  2672.         scripting languages, for example Perl, have their own
    2673. 

  2673.         buffering for output - this can be disabled by setting the
    2674. 

  2674.         <code>$|</code> special variable to 1. Of course this does
    2675. 

  2675.         increase the overall number of packets being transmitted,
    2676. 

  2676.         which can result in a sense of slowness for the end
    2677. 

  2677.         user.</p>
    2678. 

    2679. 

  2679.         <p>Prior to 1.3, you needed to use "nph-" scripts to
    2680. 

  2680.         accomplish non-buffering. Today, the only difference
    2681. 

  2681.         between nph scripts and normal scripts is that nph scripts
    2682. 

  2682.         require the full HTTP headers to be sent.</p>
    2683. 

  2683.         <hr />
    2684. 

  2684.       </li>
    2685. 

    2686. 

  2686.       <li>
    2687. 

  2687.         <a id="cgi-spec" name="cgi-spec"><strong>Where can I find
    2688. 

  2688.         the "CGI specification"?</strong></a> 
    2689. 

    2690. 

  2690.         <p>The Common Gateway Interface (CGI) specification can be
    2691. 

  2691.         found at the original NCSA site &lt; <a
    2692. 

  2692.         href="http://hoohoo.ncsa.uiuc.edu/cgi/interface.html"><samp>
    2693. 

  2693.         http://hoohoo.ncsa.uiuc.edu/cgi/interface.html</samp></a>&gt;.
    2694. 

  2694.         This version hasn't been updated since 1995, and there have
    2695. 

  2695.         been some efforts to update it.</p>
    2696. 

    2697. 

  2697.         <p>A new draft is being worked on with the intent of making
    2698. 

  2698.         it an informational RFC; you can find out more about this
    2699. 

  2699.         project at &lt;<a
    2700. 

  2700.         href="http://web.golux.com/coar/cgi/"><samp>http://web.golux.com/coar/cgi/</samp></a>&gt;.</p>
    2701. 

  2701.         <hr />
    2702. 

  2702.       </li>
    2703. 

    2704. 

  2704.       <li>
    2705. 

  2705.         <a id="fastcgi" name="fastcgi"><strong>Why isn't FastCGI
    2706. 

  2706.         included with Apache any more?</strong></a> 
    2707. 

    2708. 

  2708.         <p>The simple answer is that it was becoming too difficult
    2709. 

  2709.         to keep the version being included with Apache synchronized
    2710. 

  2710.         with the master copy at the <a
    2711. 

  2711.         href="http://www.fastcgi.com/">FastCGI web site</a>. When a
    2712. 

  2712.         new version of Apache was released, the version of the
    2713. 

  2713.         FastCGI module included with it would soon be out of
    2714. 

  2714.         date.</p>
    2715. 

    2716. 

  2716.         <p>You can still obtain the FastCGI module for Apache from
    2717. 

  2717.         the master FastCGI web site.</p>
    2718. 

  2718.         <hr />
    2719. 

  2719.       </li>
    2720. 

    2721. 

  2721.       <li>
    2722. 

  2722.         <a id="ssi-part-i" name="ssi-part-i"><strong>How do I
    2723. 

  2723.         enable SSI (parsed HTML)?</strong></a> 
    2724. 

    2725. 

  2725.         <p>SSI (an acronym for Server-Side Include) directives
    2726. 

  2726.         allow static HTML documents to be enhanced at run-time
    2727. 

  2727.         (<em>e.g.</em>, when delivered to a client by Apache). The
    2728. 

  2728.         format of SSI directives is covered in the <a
    2729. 

  2729.         href="../mod/mod_include.html">mod_include manual</a>;
    2730. 

  2730.         suffice it to say that Apache supports not only SSI but
    2731. 

  2731.         xSSI (eXtended SSI) directives.</p>
    2732. 

    2733. 

  2733.         <p>Processing a document at run-time is called
    2734. 

  2734.         <em>parsing</em> it; hence the term "parsed HTML" sometimes
    2735. 

  2735.         used for documents that contain SSI instructions. Parsing
    2736. 

  2736.         tends to be resource-consumptive compared to serving static
    2737. 

  2737.         files, and is not enabled by default. It can also interfere
    2738. 

  2738.         with the cachability of your documents, which can put a
    2739. 

  2739.         further load on your server. (See the <a
    2740. 

  2740.         href="#ssi-part-ii">next question</a> for more information
    2741. 

  2741.         about this.)</p>
    2742. 

    2743. 

  2743.         <p>To enable SSI processing, you need to</p>
    2744. 

    2745. 

  2745.         <ul>
    2746. 

  2746.           <li>Build your server with the <a
    2747. 

  2747.           href="../mod/mod_include.html"><samp>mod_include</samp></a>
    2748. 

  2748.           module. This is normally compiled in by default.</li>
    2749. 

    2750. 

  2750.           <li>Make sure your server configuration files have an <a
    2751. 

  2751.           href="../mod/core.html#options"><samp>Options</samp></a>
    2752. 

  2752.           directive which permits <samp>Includes</samp>.</li>
    2753. 

    2754. 

  2754.           <li>
    2755. 

  2755.             Make sure that the directory where you want the SSI
    2756. 

  2756.             documents to live is covered by the "server-parsed"
    2757. 

  2757.             content handler, either explicitly or in some ancestral
    2758. 

  2758.             location. That can be done with the following <a
    2759. 

  2759.             href="../mod/mod_mime.html#addhandler"><samp>AddHandler</samp></a>
    2760. 

  2760.             directive: 
    2761. 

    2762. 

  2762.             <dl>
    2763. 

  2763.               <dd><code>AddHandler server-parsed .shtml</code></dd>
    2764. 

  2764.             </dl>
    2765. 

    2766. 

  2766.             <p>This indicates that all files ending in ".shtml" in
    2767. 

  2767.             that location (or its descendants) should be parsed.
    2768. 

  2768.             Note that using ".html" will cause all normal HTML
    2769. 

  2769.             files to be parsed, which may put an inordinate load on
    2770. 

  2770.             your server.</p>
    2771. 

  2771.           </li>
    2772. 

  2772.         </ul>
    2773. 

    2774. 

  2774.         <p>For additional information, see the <cite>Apache
    2775. 

  2775.         Week</cite> article on <a
    2776. 

  2776.         href="http://www.apacheweek.com/features/ssi"
    2777. 

  2777.         rel="Help"><cite>Using Server Side Includes</cite></a>.</p>
    2778. 

  2778.         <hr />
    2779. 

  2779.       </li>
    2780. 

    2781. 

  2781.       <li>
    2782. 

  2782.         <a id="ssi-part-ii" name="ssi-part-ii"><strong>Why don't my
    2783. 

  2783.         parsed files get cached?</strong></a> 
    2784. 

    2785. 

  2785.         <p>Since the server is performing run-time processing of
    2786. 

  2786.         your SSI directives, which may change the content shipped
    2787. 

  2787.         to the client, it can't know at the time it starts parsing
    2788. 

  2788.         what the final size of the result will be, or whether the
    2789. 

  2789.         parsed result will always be the same. This means that it
    2790. 

  2790.         can't generate <samp>Content-Length</samp> or
    2791. 

  2791.         <samp>Last-Modified</samp> headers. Caches commonly work by
    2792. 

  2792.         comparing the <samp>Last-Modified</samp> of what's in the
    2793. 

  2793.         cache with that being delivered by the server. Since the
    2794. 

  2794.         server isn't sending that header for a parsed document,
    2795. 

  2795.         whatever's doing the caching can't tell whether the
    2796. 

  2796.         document has changed or not - and so fetches it again to be
    2797. 

  2797.         on the safe side.</p>
    2798. 

    2799. 

  2799.         <p>You can work around this in some cases by causing an
    2800. 

  2800.         <samp>Expires</samp> header to be generated. (See the <a
    2801. 

  2801.         href="../mod/mod_expires.html"
    2802. 

  2802.         rel="Help"><samp>mod_expires</samp></a> documentation for
    2803. 

  2803.         more details.) Another possibility is to use the <a
    2804. 

  2804.         href="../mod/mod_include.html#xbithack"
    2805. 

  2805.         rel="Help"><samp>XBitHack Full</samp></a> mechanism, which
    2806. 

  2806.         tells Apache to send (under certain circumstances detailed
    2807. 

  2807.         in the XBitHack directive description) a
    2808. 

  2808.         <samp>Last-Modified</samp> header based upon the last
    2809. 

  2809.         modification time of the file being parsed. Note that this
    2810. 

  2810.         may actually be lying to the client if the parsed file
    2811. 

  2811.         doesn't change but the SSI-inserted content does; if the
    2812. 

  2812.         included content changes often, this can result in stale
    2813. 

  2813.         copies being cached.</p>
    2814. 

  2814.         <hr />
    2815. 

  2815.       </li>
    2816. 

    2817. 

  2817.       <li>
    2818. 

  2818.         <a id="ssi-part-iii" name="ssi-part-iii"><strong>How can I
    2819. 

  2819.         have my script output parsed?</strong></a> 
    2820. 

    2821. 

  2821.         <p>So you want to include SSI directives in the output from
    2822. 

  2822.         your CGI script, but can't figure out how to do it? The
    2823. 

  2823.         short answer is "you can't." This is potentially a security
    2824. 

  2824.         liability and, more importantly, it can not be cleanly
    2825. 

  2825.         implemented under the current server API. The best
    2826. 

  2826.         workaround is for your script itself to do what the SSIs
    2827. 

  2827.         would be doing. After all, it's generating the rest of the
    2828. 

  2828.         content.</p>
    2829. 

    2830. 

  2830.         <p>This is a feature The Apache Group hopes to add in the
    2831. 

  2831.         next major release after 1.3.</p>
    2832. 

  2832.         <hr />
    2833. 

  2833.       </li>
    2834. 

    2835. 

  2835.       <li>
    2836. 

  2836.         <a id="ssi-part-iv" name="ssi-part-iv"><strong>SSIs don't
    2837. 

  2837.         work for VirtualHosts and/or user home
    2838. 

  2838.         directories.</strong></a> 
    2839. 

    2840. 

  2840.         <p>This is almost always due to having some setting in your
    2841. 

  2841.         config file that sets "Options Includes" or some other
    2842. 

  2842.         setting for your DocumentRoot but not for other
    2843. 

  2843.         directories. If you set it inside a Directory section, then
    2844. 

  2844.         that setting will only apply to that directory.</p>
    2845. 

  2845.         <hr />
    2846. 

  2846.       </li>
    2847. 

    2848. 

  2848.       <li>
    2849. 

  2849.         <a id="errordocssi" name="errordocssi"><strong>How can I
    2850. 

  2850.         use <code>ErrorDocument</code> and SSI to simplify
    2851. 

  2851.         customized error messages?</strong></a> 
    2852. 

    2853. 

  2853.         <p>Have a look at <a href="custom_errordocs.html">this
    2854. 

  2854.         document</a>. It shows in example form how you can a
    2855. 

  2855.         combination of XSSI and negotiation to tailor a set of
    2856. 

  2856.         <code>ErrorDocument</code>s to your personal taste, and
    2857. 

  2857.         returning different internationalized error responses based
    2858. 

  2858.         on the client's native language.</p>
    2859. 

  2859.         <hr />
    2860. 

  2860.       </li>
    2861. 

    2862. 

  2862.       <li>
    2863. 

  2863.         <a id="remote-user-var" name="remote-user-var"><strong>Why
    2864. 

  2864.         is the environment variable <samp>REMOTE_USER</samp> not
    2865. 

  2865.         set?</strong></a> 
    2866. 

    2867. 

  2867.         <p>This variable is set and thus available in SSI or CGI
    2868. 

  2868.         scripts <strong>if and only if</strong> the requested
    2869. 

  2869.         document was protected by access authentication. For an
    2870. 

  2870.         explanation on how to implement these restrictions, see <a
    2871. 

  2871.         href="http://www.apacheweek.com/"><cite>Apache
    2872. 

  2872.         Week</cite></a>'s articles on <a
    2873. 

  2873.         href="http://www.apacheweek.com/features/userauth"><cite>Using
    2874. 

  2874.         User Authentication</cite></a> or <a
    2875. 

  2875.         href="http://www.apacheweek.com/features/dbmauth"><cite>DBM
    2876. 

  2876.         User Authentication</cite></a>.</p>
    2877. 

    2878. 

  2878.         <p>Hint: When using a CGI script to receive the data of a
    2879. 

  2879.         HTML <samp>FORM</samp> notice that protecting the document
    2880. 

  2880.         containing the <samp>FORM</samp> is not sufficient to
    2881. 

  2881.         provide <samp>REMOTE_USER</samp> to the CGI script. You
    2882. 

  2882.         have to protect the CGI script, too. Or alternatively only
    2883. 

  2883.         the CGI script (then authentication happens only after
    2884. 

  2884.         filling out the form).</p>
    2885. 

  2885.         <hr />
    2886. 

  2886.       </li>
    2887. 

    2888. 

  2888.       <li>
    2889. 

  2889.         <a id="user-cgi" name="user-cgi"><strong>How do I allow
    2890. 

  2890.         each of my user directories to have a cgi-bin
    2891. 

  2891.         directory?</strong></a> 
    2892. 

    2893. 

  2893.         <p>Remember that CGI execution does not need to be
    2894. 

  2894.         restricted only to cgi-bin directories. You can <a
    2895. 

  2895.         href="#CGIoutsideScriptAlias">allow CGI script execution in
    2896. 

  2896.         arbitrary parts of your filesystem</a>.</p>
    2897. 

    2898. 

  2898.         <p>There are many ways to give each user directory a
    2899. 

  2899.         cgi-bin directory such that anything requested as
    2900. 

  2900.         <samp>http://example.com/~user/cgi-bin/program</samp> will
    2901. 

  2901.         be executed as a CGI script. Two alternatives are:</p>
    2902. 

    2903. 

  2903.         <ol>
    2904. 

  2904.           <li>
    2905. 

  2905.             Place the cgi-bin directory next to the public_html
    2906. 

  2906.             directory: 
    2907. 

    2908. 

  2908.             <dl>
    2909. 

  2909.               <dd><code>ScriptAliasMatch ^/~([^/]*)/cgi-bin/(.*)
    2910. 

  2910.               /home/$1/cgi-bin/$2</code></dd>
    2911. 

  2911.             </dl>
    2912. 

  2912.           </li>
    2913. 

    2914. 

  2914.           <li>
    2915. 

  2915.             Place the cgi-bin directory underneath the public_html
    2916. 

  2916.             directory: 
    2917. 

    2918. 

  2918.             <dl>
    2919. 

  2919.               <dd><code>&lt;Directory
    2920. 

  2920.               /home/*/public_html/cgi-bin&gt;<br />
    2921. 

  2921.                &nbsp;&nbsp;&nbsp;&nbsp;Options ExecCGI<br />
    2922. 

  2922.                &nbsp;&nbsp;&nbsp;&nbsp;SetHandler cgi-script<br />
    2923. 

  2923.                &lt;/Directory&gt;</code></dd>
    2924. 

  2924.             </dl>
    2925. 

  2925.           </li>
    2926. 

  2926.         </ol>
    2927. 

  2927.         <hr />
    2928. 

  2928.       </li>
    2929. 

  2929.     </ol>
    2930. 

  2930.     
    2931. 

  2931.     
    2932. 

  2932.   </body>
    2933. 

  2933. </html>
    2934. 

  2934. 

  2935. 

  2936.     
    2937. 

  2937. 

  2938. 

  2939. 

  2940. 

  2941. 

  2942. 

  2943. 

  2944. 

  2945.       
    2946. 

  2946.       
    2947. 

  2947.     
    2948. 

  2948. 

  2949.     <h3>G. Authentication and Access Restrictions</h3>
    2950. 

  2950. 

  2951.     <ol>
    2952. 

  2952.       <li>
    2953. 

  2953.         <a id="dnsauth" name="dnsauth"><strong>Why isn't
    2954. 

  2954.         restricting access by host or domain name working
    2955. 

  2955.         correctly?</strong></a> 
    2956. 

  2956. 

  2957.         <p>Two of the most common causes of this are:</p>
    2958. 

  2958. 

  2959.         <ol>
    2960. 

  2960.           <li><strong>An error, inconsistency, or unexpected
    2961. 

  2961.           mapping in the DNS registration</strong><br />
    2962. 

  2962.            This happens frequently: your configuration restricts
    2963. 

  2963.           access to <samp>Host.FooBar.Com</samp>, but you can't get
    2964. 

  2964.           in from that host. The usual reason for this is that
    2965. 

  2965.           <samp>Host.FooBar.Com</samp> is actually an alias for
    2966. 

  2966.           another name, and when Apache performs the
    2967. 

  2967.           address-to-name lookup it's getting the <em>real</em>
    2968. 

  2968.           name, not <samp>Host.FooBar.Com</samp>. You can verify
    2969. 

  2969.           this by checking the reverse lookup yourself. The easiest
    2970. 

  2970.           way to work around it is to specify the correct host name
    2971. 

  2971.           in your configuration.</li>
    2972. 

  2972. 

  2973.           <li>
    2974. 

  2974.             <strong>Inadequate checking and verification in your
    2975. 

  2975.             configuration of Apache</strong><br />
    2976. 

  2976.              If you intend to perform access checking and
    2977. 

  2977.             restriction based upon the client's host or domain
    2978. 

  2978.             name, you really need to configure Apache to
    2979. 

  2979.             double-check the origin information it's supplied. You
    2980. 

  2980.             do this by adding the <samp>-DMAXIMUM_DNS</samp> clause
    2981. 

  2981.             to the <samp>EXTRA_CFLAGS</samp> definition in your
    2982. 

  2982.             <samp>Configuration</samp> file. For example: 
    2983. 

  2983. 

  2984.             <dl>
    2985. 

  2985.               <dd><code>EXTRA_CFLAGS=-DMAXIMUM_DNS</code></dd>
    2986. 

  2986.             </dl>
    2987. 

  2987. 

  2988.             <p>This will cause Apache to be very paranoid about
    2989. 

  2989.             making sure a particular host address is
    2990. 

  2990.             <em>really</em> assigned to the name it claims to be.
    2991. 

  2991.             Note that this <em>can</em> incur a significant
    2992. 

  2992.             performance penalty, however, because of all the name
    2993. 

  2993.             resolution requests being sent to a nameserver.</p>
    2994. 

  2994.           </li>
    2995. 

  2995.         </ol>
    2996. 

  2996.         <hr />
    2997. 

  2997.       </li>
    2998. 

  2998. 

  2999.       <li>
    3000. 

  3000.         <a id="user-authentication"
    3001. 

  3001.         name="user-authentication"><strong>How do I set up Apache
    3002. 

  3002.         to require a username and password to access certain
    3003. 

  3003.         documents?</strong></a> 
    3004. 

  3004. 

  3005.         <p>There are several ways to do this; some of the more
    3006. 

  3006.         popular ones are to use the <a
    3007. 

  3007.         href="../mod/mod_auth.html">mod_auth</a>, <a
    3008. 

  3008.         href="../mod/mod_auth_db.html">mod_auth_db</a>, or <a
    3009. 

  3009.         href="../mod/mod_auth_dbm.html">mod_auth_dbm</a>
    3010. 

  3010.         modules.</p>
    3011. 

  3011. 

  3012.         <p>For an explanation on how to implement these
    3013. 

  3013.         restrictions, see <a
    3014. 

  3014.         href="http://www.apacheweek.com/"><cite>Apache
    3015. 

  3015.         Week</cite></a>'s articles on <a
    3016. 

  3016.         href="http://www.apacheweek.com/features/userauth"><cite>Using
    3017. 

  3017.         User Authentication</cite></a> or <a
    3018. 

  3018.         href="http://www.apacheweek.com/features/dbmauth"><cite>DBM
    3019. 

  3019.         User Authentication</cite></a>.</p>
    3020. 

  3020.         <hr />
    3021. 

  3021.       </li>
    3022. 

  3022. 

  3023.       <li>
    3024. 

  3024.         <a id="remote-auth-only"
    3025. 

  3025.         name="remote-auth-only"><strong>How do I set up Apache to
    3026. 

  3026.         allow access to certain documents only if a site is either
    3027. 

  3027.         a local site <em>or</em> the user supplies a password and
    3028. 

  3028.         username?</strong></a> 
    3029. 

  3029. 

  3030.         <p>Use the <a href="../mod/core.html#satisfy">Satisfy</a>
    3031. 

  3031.         directive, in particular the <code>Satisfy Any</code>
    3032. 

  3032.         directive, to require that only one of the access
    3033. 

  3033.         restrictions be met. For example, adding the following
    3034. 

  3034.         configuration to a <samp>.htaccess</samp> or server
    3035. 

  3035.         configuration file would restrict access to people who
    3036. 

  3036.         either are accessing the site from a host under domain.com
    3037. 

  3037.         or who can supply a valid username and password:</p>
    3038. 

  3038. 

  3039.         <dl>
    3040. 

  3040.           <dd><code>Deny from all<br />
    3041. 

  3041.            Allow from .domain.com<br />
    3042. 

  3042.            AuthType Basic<br />
    3043. 

  3043.            AuthUserFile /usr/local/apache/conf/htpasswd.users<br />
    3044. 

  3044.            AuthName "special directory"<br />
    3045. 

  3045.            Require valid-user<br />
    3046. 

  3046.            Satisfy any</code></dd>
    3047. 

  3047.         </dl>
    3048. 

  3048. 

  3049.         <p>See the <a href="#user-authentication">user
    3050. 

  3050.         authentication</a> question and the <a
    3051. 

  3051.         href="../mod/mod_access.html">mod_access</a> module for
    3052. 

  3052.         details on how the above directives work.</p>
    3053. 

  3053.         <hr />
    3054. 

  3054.       </li>
    3055. 

  3055. 

  3056.       <li>
    3057. 

  3057.         <a id="authauthoritative"
    3058. 

  3058.         name="authauthoritative"><strong>Why does my authentication
    3059. 

  3059.         give me a server error?</strong></a> 
    3060. 

  3060. 

  3061.         <p>Under normal circumstances, the Apache access control
    3062. 

  3062.         modules will pass unrecognized user IDs on to the next
    3063. 

  3063.         access control module in line. Only if the user ID is
    3064. 

  3064.         recognized and the password is validated (or not) will it
    3065. 

  3065.         give the usual success or "authentication failed"
    3066. 

  3066.         messages.</p>
    3067. 

  3067. 

  3068.         <p>However, if the last access module in line 'declines'
    3069. 

  3069.         the validation request (because it has never heard of the
    3070. 

  3070.         user ID or because it is not configured), the
    3071. 

  3071.         <samp>http_request</samp> handler will give one of the
    3072. 

  3072.         following, confusing, errors:</p>
    3073. 

  3073. 

  3074.         <ul>
    3075. 

  3075.           <li><samp>check access</samp></li>
    3076. 

  3076. 

  3077.           <li><samp>check user. No user file?</samp></li>
    3078. 

  3078. 

  3079.           <li><samp>check access. No groups file?</samp></li>
    3080. 

  3080.         </ul>
    3081. 

  3081. 

  3082.         <p>This does <em>not</em> mean that you have to add an
    3083. 

  3083.         '<samp>AuthUserFile&nbsp;/dev/null</samp>' line as some
    3084. 

  3084.         magazines suggest!</p>
    3085. 

  3085. 

  3086.         <p>The solution is to ensure that at least the last module
    3087. 

  3087.         is authoritative and <strong>CONFIGURED</strong>. By
    3088. 

  3088.         default, <samp>mod_auth</samp> is authoritative and will
    3089. 

  3089.         give an OK/Denied, but only if it is configured with the
    3090. 

  3090.         proper <samp>AuthUserFile</samp>. Likewise, if a valid
    3091. 

  3091.         group is required. (Remember that the modules are processed
    3092. 

  3092.         in the reverse order from that in which they appear in your
    3093. 

  3093.         compile-time <samp>Configuration</samp> file.)</p>
    3094. 

  3094. 

  3095.         <p>A typical situation for this error is when you are using
    3096. 

  3096.         the <samp>mod_auth_dbm</samp>, <samp>mod_auth_msql</samp>,
    3097. 

  3097.         <samp>mod_auth_mysql</samp>, <samp>mod_auth_anon</samp> or
    3098. 

  3098.         <samp>mod_auth_cookie</samp> modules on their own. These
    3099. 

  3099.         are by default <strong>not</strong> authoritative, and this
    3100. 

  3100.         will pass the buck on to the (non-existent) next
    3101. 

  3101.         authentication module when the user ID is not in their
    3102. 

  3102.         respective database. Just add the appropriate
    3103. 

  3103.         '<samp><em>XXX</em>Authoritative yes</samp>' line to the
    3104. 

  3104.         configuration.</p>
    3105. 

  3105. 

  3106.         <p>In general it is a good idea (though not terribly
    3107. 

  3107.         efficient) to have the file-based <samp>mod_auth</samp> a
    3108. 

  3108.         module of last resort. This allows you to access the web
    3109. 

  3109.         server with a few special passwords even if the databases
    3110. 

  3110.         are down or corrupted. This does cost a file
    3111. 

  3111.         open/seek/close for each request in a protected area.</p>
    3112. 

  3112.         <hr />
    3113. 

  3113.       </li>
    3114. 

  3114. 

  3115.       <li>
    3116. 

  3116.         <a id="auth-on-same-machine"
    3117. 

  3117.         name="auth-on-same-machine"><strong>Do I have to keep the
    3118. 

  3118.         (mSQL) authentication information on the same
    3119. 

  3119.         machine?</strong></a> 
    3120. 

  3120. 

  3121.         <p>Some organizations feel very strongly about keeping the
    3122. 

  3122.         authentication information on a different machine than the
    3123. 

  3123.         webserver. With the <samp>mod_auth_msql</samp>,
    3124. 

  3124.         <samp>mod_auth_mysql</samp>, and other SQL modules
    3125. 

  3125.         connecting to (R)DBMses this is quite possible. Just
    3126. 

  3126.         configure an explicit host to contact.</p>
    3127. 

  3127. 

  3128.         <p>Be aware that with mSQL and Oracle, opening and closing
    3129. 

  3129.         these database connections is very expensive and time
    3130. 

  3130.         consuming. You might want to look at the code in the
    3131. 

  3131.         <samp>auth_*</samp> modules and play with the compile time
    3132. 

  3132.         flags to alleviate this somewhat, if your RDBMS licences
    3133. 

  3133.         allow for it.</p>
    3134. 

  3134.         <hr />
    3135. 

  3135.       </li>
    3136. 

  3136. 

  3137.       <li>
    3138. 

  3138.         <a id="msql-slow" name="msql-slow"><strong>Why is my mSQL
    3139. 

  3139.         authentication terribly slow?</strong></a> 
    3140. 

  3140. 

  3141.         <p>You have probably configured the Host by specifying a
    3142. 

  3142.         FQHN, and thus the <samp>libmsql</samp> will use a full
    3143. 

  3143.         blown TCP/IP socket to talk to the database, rather than a
    3144. 

  3144.         fast internal device. The <samp>libmsql</samp>, the mSQL
    3145. 

  3145.         FAQ, and the <samp>mod_auth_msql</samp> documentation warn
    3146. 

  3146.         you about this. If you have to use different hosts, check
    3147. 

  3147.         out the <samp>mod_auth_msql</samp> code for some compile
    3148. 

  3148.         time flags which might - or might not - suit you.</p>
    3149. 

  3149.         <hr />
    3150. 

  3150.       </li>
    3151. 

  3151. 

  3152.       <li>
    3153. 

  3153.         <a id="passwdauth" name="passwdauth"><strong>Can I use my
    3154. 

  3154.         <samp>/etc/passwd</samp> file for Web page
    3155. 

  3155.         authentication?</strong></a> 
    3156. 

  3156. 

  3157.         <p>Yes, you can - but it's a <strong>very bad
    3158. 

  3158.         idea</strong>. Here are some of the reasons:</p>
    3159. 

  3159. 

  3160.         <ul>
    3161. 

  3161.           <li>The Web technology provides no governors on how often
    3162. 

  3162.           or how rapidly password (authentication failure) retries
    3163. 

  3163.           can be made. That means that someone can hammer away at
    3164. 

  3164.           your system's <samp>root</samp> password using the Web,
    3165. 

  3165.           using a dictionary or similar mass attack, just as fast
    3166. 

  3166.           as the wire and your server can handle the requests. Most
    3167. 

  3167.           operating systems these days include attack detection
    3168. 

  3168.           (such as <em>n</em> failed passwords for the same account
    3169. 

  3169.           within <em>m</em> seconds) and evasion (breaking the
    3170. 

  3170.           connection, disabling the account under attack, disabling
    3171. 

  3171.           <em>all</em> logins from that source, <em>et
    3172. 

  3172.           cetera</em>), but the Web does not.</li>
    3173. 

  3173. 

  3174.           <li>An account under attack isn't notified (unless the
    3175. 

  3175.           server is heavily modified); there's no "You have 19483
    3176. 

  3176.           login failures" message when the legitimate owner logs
    3177. 

  3177.           in.</li>
    3178. 

  3178. 

  3179.           <li>Without an exhaustive and error-prone examination of
    3180. 

  3180.           the server logs, you can't tell whether an account has
    3181. 

  3181.           been compromised. Detecting that an attack has occurred,
    3182. 

  3182.           or is in progress, is fairly obvious, though -
    3183. 

  3183.           <em>if</em> you look at the logs.</li>
    3184. 

  3184. 

  3185.           <li>Web authentication passwords (at least for Basic
    3186. 

  3186.           authentication) generally fly across the wire, and
    3187. 

  3187.           through intermediate proxy systems, in what amounts to
    3188. 

  3188.           plain text. "O'er the net we go/Caching all the way;/O
    3189. 

  3189.           what fun it is to surf/Giving my password away!"</li>
    3190. 

    3191. 

  3191.           <li>Since HTTP is stateless, information about the
    3192. 

  3192.           authentication is transmitted <em>each and every
    3193. 

  3193.           time</em> a request is made to the server. Essentially,
    3194. 

  3194.           the client caches it after the first successful access,
    3195. 

  3195.           and transmits it without asking for all subsequent
    3196. 

  3196.           requests to the same server.</li>
    3197. 

  3197. 

  3198.           <li>It's relatively trivial for someone on your system to
    3199. 

  3199.           put up a page that will steal the cached password from a
    3200. 

  3200.           client's cache without them knowing. Can you say
    3201. 

  3201.           "password grabber"?</li>
    3202. 

  3202.         </ul>
    3203. 

  3203. 

  3204.         <p>If you still want to do this in light of the above
    3205. 

  3205.         disadvantages, the method is left as an exercise for the
    3206. 

  3206.         reader. It'll void your Apache warranty, though, and you'll
    3207. 

  3207.         lose all accumulated UNIX guru points.</p>
    3208. 

  3208.         <hr />
    3209. 

  3209.       </li>
    3210. 

  3210. 

  3211.       <li>
    3212. 

  3212.         <a id="prompted-twice" name="prompted-twice"><strong>Why
    3213. 

  3213.         does Apache ask for my password twice before serving a
    3214. 

  3214.         file?</strong></a> 
    3215. 

  3215. 

  3216.         <p>If the hostname under which you are accessing the server
    3217. 

  3217.         is different than the hostname specified in the <a
    3218. 

  3218.         href="../mod/core.html#servername"><code>ServerName</code></a>
    3219. 

  3219.         directive, then depending on the setting of the <a
    3220. 

  3220.         href="../mod/core.html#usecanonicalname"><code>UseCanonicalName</code></a>
    3221. 

  3221.         directive, Apache will redirect you to a new hostname when
    3222. 

  3222.         constructing self-referential URLs. This happens, for
    3223. 

  3223.         example, in the case where you request a directory without
    3224. 

  3224.         including the trailing slash.</p>
    3225. 

  3225. 

  3226.         <p>When this happens, Apache will ask for authentication
    3227. 

  3227.         once under the original hostname, perform the redirect, and
    3228. 

  3228.         then ask again under the new hostname. For security
    3229. 

  3229.         reasons, the browser must prompt again for the password
    3230. 

  3230.         when the host name changes.</p>
    3231. 

  3231. 

  3232.         <p>To eliminate this problem you should</p>
    3233. 

  3233. 

  3234.         <ol>
    3235. 

  3235.           <li>Always use the trailing slash when requesting
    3236. 

  3236.           directories;</li>
    3237. 

  3237. 

  3238.           <li>Change the <code>ServerName</code> to match the name
    3239. 

  3239.           you are using in the URL; and/or</li>
    3240. 

  3240. 

  3241.           <li>Set <code>UseCanonicalName off</code>.</li>
    3242. 

  3242.         </ol>
    3243. 

  3243.         <hr />
    3244. 

  3244.       </li>
    3245. 

  3245.     </ol>
    3246. 

  3246.     
    3247. 

  3247.     
    3248. 

  3248.   </body>
    3249. 

  3249. </html>
    3250. 

  3250. 

  3251. 

  3252.     
    3253. 

  3253. 

  3254. 

  3255. 

  3256. 

  3257. 

  3258. 

  3259. 

  3260. 

  3261.       
    3262. 

  3262.       
    3263. 

  3263.     
    3264. 

  3264. 

  3265.     <h3>H. URL Rewriting</h3>
    3266. 

  3266. 

  3267.     <ol>
    3268. 

  3268.       <li>
    3269. 

  3269.         <a id="rewrite-more-config"
    3270. 

  3270.         name="rewrite-more-config"><strong>Where can I find
    3271. 

  3271.         mod_rewrite rulesets which already solve particular
    3272. 

  3272.         URL-related problems?</strong></a> 
    3273. 

  3273. 

  3274.         <p>There is a collection of <a
    3275. 

  3275.         href="http://www.engelschall.com/pw/apache/rewriteguide/">Practical
    3276. 

  3276.         Solutions for URL-Manipulation</a> where you can find all
    3277. 

  3277.         typical solutions the author of <a
    3278. 

  3278.         href="../mod/mod_rewrite.html"><samp>mod_rewrite</samp></a>
    3279. 

  3279.         currently knows of. If you have more interesting rulesets
    3280. 

  3280.         which solve particular problems not currently covered in
    3281. 

  3281.         this document, send it to <a
    3282. 

  3282.         href="mailto:rse@apache.org">Ralf S. Engelschall</a> for
    3283. 

  3283.         inclusion. The other webmasters will thank you for avoiding
    3284. 

  3284.         the reinvention of the wheel.</p>
    3285. 

  3285.         <hr />
    3286. 

  3286.       </li>
    3287. 

  3287. 

  3288.       <li>
    3289. 

  3289.         <a id="rewrite-article"
    3290. 

  3290.         name="rewrite-article"><strong>Where can I find any
    3291. 

  3291.         published information about URL-manipulations and
    3292. 

  3292.         mod_rewrite?</strong></a> 
    3293. 

  3293. 

  3294.         <p>There is an article from <a
    3295. 

  3295.         href="mailto:rse@apache.org">Ralf S. Engelschall</a> about
    3296. 

  3296.         URL-manipulations based on <a
    3297. 

  3297.         href="../mod/mod_rewrite.html"><samp>mod_rewrite</samp></a>
    3298. 

  3298.         in the "iX Multiuser Multitasking Magazin" issue #12/96.
    3299. 

  3299.         The german (original) version can be read online at &lt;<a
    3300. 

  3300.         href="http://www.heise.de/ix/artikel/9612149/">http://www.heise.de/ix/artikel/9612149/</a>&gt;,
    3301. 

  3301.         the English (translated) version can be found at &lt;<a
    3302. 

  3302.         href="http://www.heise.de/ix/artikel/E/9612149/">http://www.heise.de/ix/artikel/E/9612149/</a>&gt;.</p>
    3303. 

  3303.         <hr />
    3304. 

  3304.       </li>
    3305. 

  3305. 

  3306.       <li>
    3307. 

  3307.         <a id="rewrite-complexity"
    3308. 

  3308.         name="rewrite-complexity"><strong>Why is mod_rewrite so
    3309. 

  3309.         difficult to learn and seems so complicated?</strong></a> 
    3310. 

  3310. 

  3311.         <p>Hmmm... there are a lot of reasons. First, mod_rewrite
    3312. 

  3312.         itself is a powerful module which can help you in really
    3313. 

  3313.         <strong>all</strong> aspects of URL rewriting, so it can be
    3314. 

  3314.         no trivial module per definition. To accomplish its hard
    3315. 

  3315.         job it uses software leverage and makes use of a powerful
    3316. 

  3316.         regular expression library by Henry Spencer which is an
    3317. 

  3317.         integral part of Apache since its version 1.2. And regular
    3318. 

  3318.         expressions itself can be difficult to newbies, while
    3319. 

  3319.         providing the most flexible power to the advanced
    3320. 

  3320.         hacker.</p>
    3321. 

  3321. 

  3322.         <p>On the other hand mod_rewrite has to work inside the
    3323. 

  3323.         Apache API environment and needs to do some tricks to fit
    3324. 

  3324.         there. For instance the Apache API as of 1.x really was not
    3325. 

  3325.         designed for URL rewriting at the <tt>.htaccess</tt> level
    3326. 

  3326.         of processing. Or the problem of multiple rewrites in
    3327. 

  3327.         sequence, which is also not handled by the API per design.
    3328. 

  3328.         To provide this features mod_rewrite has to do some special
    3329. 

  3329.         (but API compliant!) handling which leads to difficult
    3330. 

  3330.         processing inside the Apache kernel. While the user usually
    3331. 

  3331.         doesn't see anything of this processing, it can be
    3332. 

  3332.         difficult to find problems when some of your RewriteRules
    3333. 

  3333.         seem not to work.</p>
    3334. 

  3334.         <hr />
    3335. 

  3335.       </li>
    3336. 

  3336. 

  3337.       <li>
    3338. 

  3338.         <a id="rewrite-dontwork"
    3339. 

  3339.         name="rewrite-dontwork"><strong>What can I do if my
    3340. 

  3340.         RewriteRules don't work as expected?</strong></a> 
    3341. 

    3342. 

  3342.         <p>Use "<samp>RewriteLog somefile</samp>" and
    3343. 

  3343.         "<samp>RewriteLogLevel 9</samp>" and have a precise look at
    3344. 

  3344.         the steps the rewriting engine performs. This is really the
    3345. 

  3345.         only one and best way to debug your rewriting
    3346. 

  3346.         configuration.</p>
    3347. 

  3347.         <hr />
    3348. 

  3348.       </li>
    3349. 

  3349. 

  3350.       <li>
    3351. 

  3351.         <a id="rewrite-prefixdocroot"
    3352. 

  3352.         name="rewrite-prefixdocroot"><strong>Why don't some of my
    3353. 

  3353.         URLs get prefixed with DocumentRoot when using
    3354. 

  3354.         mod_rewrite?</strong></a> 
    3355. 

  3355. 

  3356.         <p>If the rule starts with <samp>/somedir/...</samp> make
    3357. 

  3357.         sure that really no <samp>/somedir</samp> exists on the
    3358. 

  3358.         filesystem if you don't want to lead the URL to match this
    3359. 

  3359.         directory, <em>i.e.</em>, there must be no root directory
    3360. 

  3360.         named <samp>somedir</samp> on the filesystem. Because if
    3361. 

  3361.         there is such a directory, the URL will not get prefixed
    3362. 

  3362.         with DocumentRoot. This behavior looks ugly, but is really
    3363. 

  3363.         important for some other aspects of URL rewriting.</p>
    3364. 

  3364.         <hr />
    3365. 

  3365.       </li>
    3366. 

  3366. 

  3367.       <li>
    3368. 

  3368.         <a id="rewrite-nocase" name="rewrite-nocase"><strong>How
    3369. 

  3369.         can I make all my URLs case-insensitive with
    3370. 

  3370.         mod_rewrite?</strong></a> 
    3371. 

  3371. 

  3372.         <p>You can't! The reasons are: first, that, case
    3373. 

  3373.         translations for arbitrary length URLs cannot be done
    3374. 

  3374.         <em>via</em> regex patterns and corresponding
    3375. 

  3375.         substitutions. One needs a per-character pattern like the
    3376. 

  3376.         sed/Perl <samp>tr|..|..|</samp> feature. Second, just
    3377. 

  3377.         making URLs always upper or lower case does not solve the
    3378. 

  3378.         whole problem of case-INSENSITIVE URLs, because URLs
    3379. 

  3379.         actually have to be rewritten to the correct case-variant
    3380. 

  3380.         for the file residing on the filesystem in order to allow
    3381. 

  3381.         Apache to access the file. And the Unix filesystem is
    3382. 

  3382.         always case-SENSITIVE.</p>
    3383. 

  3383. 

  3384.         <p>But there is a module named <code><a
    3385. 

  3385.         href="../mod/mod_speling.html">mod_speling.c</a></code> in
    3386. 

  3386.         the Apache distribution. Try this module to help correct
    3387. 

  3387.         people who use mis-cased URLs.</p>
    3388. 

  3388.         <hr />
    3389. 

  3389.       </li>
    3390. 

  3390. 

  3391.       <li>
    3392. 

  3392.         <a id="rewrite-virthost"
    3393. 

  3393.         name="rewrite-virthost"><strong>Why are RewriteRules in my
    3394. 

  3394.         VirtualHost parts ignored?</strong></a> 
    3395. 

  3395. 

  3396.         <p>Because you have to enable the engine for every virtual
    3397. 

  3397.         host explicitly due to security concerns. Just add a
    3398. 

  3398.         "RewriteEngine on" to your virtual host configuration
    3399. 

  3399.         parts.</p>
    3400. 

  3400.         <hr />
    3401. 

  3401.       </li>
    3402. 

  3402. 

  3403.       <li>
    3404. 

  3404.         <a id="rewrite-envwhitespace"
    3405. 

  3405.         name="rewrite-envwhitespace"><strong>How can I use strings
    3406. 

  3406.         with whitespaces in RewriteRule's ENV flag?</strong></a> 
    3407. 

    3408. 

  3408.         <p>There is only one ugly solution: You have to surround
    3409. 

  3409.         the complete flag argument by quotation marks
    3410. 

  3410.         (<samp>"[E=...]"</samp>). Notice: The argument to quote
    3411. 

  3411.         here is not the argument to the E-flag, it is the argument
    3412. 

  3412.         of the Apache config file parser, <em>i.e.</em>, the third
    3413. 

  3413.         argument of the RewriteRule here. So you have to write
    3414. 

  3414.         <samp>"[E=any text with whitespaces]"</samp>.</p>
    3415. 

  3415.         <hr />
    3416. 

  3416.       </li>
    3417. 

  3417.     </ol>
    3418. 

  3418.     
    3419. 

  3419.     
    3420. 

  3420.   </body>
    3421. 

  3421. </html>
    3422. 

  3422. 

  3423. 

  3424.     
    3425. 

  3425. 

  3426. 

  3427. 

  3428. 

  3429. 

  3430. 

  3431. 

  3432. 

  3433.       
    3434. 

  3434.       
    3435. 

  3435.     
    3436. 

  3436. 

  3437.     <h3>I. Features</h3>
    3438. 

  3438. 

  3439.     <ol>
    3440. 

  3440.       <li>
    3441. 

  3441.         <a id="proxy" name="proxy"><strong>Does or will Apache act
    3442. 

  3442.         as a Proxy server?</strong></a> 
    3443. 

  3443. 

  3444.         <p>Apache version 1.1 and above comes with a <a
    3445. 

  3445.         href="../mod/mod_proxy.html">proxy module</a>. If compiled
    3446. 

  3446.         in, this will make Apache act as a caching-proxy
    3447. 

  3447.         server.</p>
    3448. 

  3448.         <hr />
    3449. 

  3449.       </li>
    3450. 

  3450. 

  3451.       <li>
    3452. 

  3452.         <a id="multiviews" name="multiviews"><strong>What are
    3453. 

  3453.         "multiviews"?</strong></a> 
    3454. 

  3454. 

  3455.         <p>"Multiviews" is the general name given to the Apache
    3456. 

  3456.         server's ability to provide language-specific document
    3457. 

  3457.         variants in response to a request. This is documented quite
    3458. 

  3458.         thoroughly in the <a href="../content-negotiation.html"
    3459. 

  3459.         rel="Help">content negotiation</a> description page. In
    3460. 

  3460.         addition, <cite>Apache Week</cite> carried an article on
    3461. 

  3461.         this subject entitled "<a
    3462. 

  3462.         href="http://www.apacheweek.com/features/negotiation"
    3463. 

  3463.         rel="Help"><cite>Content Negotiation
    3464. 

  3464.         Explained</cite></a>".</p>
    3465. 

  3465.         <hr />
    3466. 

  3466.       </li>
    3467. 

  3467. 

  3468.       <li>
    3469. 

  3469.         <a id="putsupport" name="putsupport"><strong>Why can't I
    3470. 

  3470.         publish to my Apache server using PUT on Netscape Gold and
    3471. 

  3471.         other programs?</strong></a> 
    3472. 

  3472. 

  3473.         <p>Because you need to install and configure a script to
    3474. 

  3474.         handle the uploaded files. This script is often called a
    3475. 

  3475.         "PUT" handler. There are several available, but they may
    3476. 

  3476.         have security problems. Using FTP uploads may be easier and
    3477. 

  3477.         more secure, at least for now. For more information, see
    3478. 

  3478.         the <cite>Apache Week</cite> article <a
    3479. 

  3479.         href="http://www.apacheweek.com/features/put"><cite>Publishing
    3480. 

  3480.         Pages with PUT</cite></a>.</p>
    3481. 

  3481.         <hr />
    3482. 

  3482.       </li>
    3483. 

  3483. 

  3484.       <li>
    3485. 

  3485.         <a id="SSL-i" name="SSL-i"><strong>Why doesn't Apache
    3486. 

  3486.         include SSL?</strong></a> 
    3487. 

  3487. 

  3488.         <p>SSL (Secure Socket Layer) data transport requires
    3489. 

  3489.         encryption, and many governments have restrictions upon the
    3490. 

  3490.         import, export, and use of encryption technology. If Apache
    3491. 

  3491.         included SSL in the base package, its distribution would
    3492. 

  3492.         involve all sorts of legal and bureaucratic issues, and it
    3493. 

  3493.         would no longer be freely available. Also, some of the
    3494. 

  3494.         technology required to talk to current clients using SSL is
    3495. 

  3495.         patented by <a href="http://www.rsa.com/">RSA Data
    3496. 

  3496.         Security</a>, who restricts its use without a license.</p>
    3497. 

  3497. 

  3498.         <p>Some SSL implementations of Apache are available,
    3499. 

  3499.         however; see the "<a
    3500. 

  3500.         href="http://httpd.apache.org/related_projects.html">related
    3501. 

  3501.         projects</a>" page at the main Apache web site.</p>
    3502. 

    3503. 

  3503.         <p>You can find out more about this topic in the
    3504. 

  3504.         <cite>Apache Week</cite> article about <a
    3505. 

  3505.         href="http://www.apacheweek.com/features/ssl"
    3506. 

  3506.         rel="Help"><cite>Apache and Secure
    3507. 

  3507.         Transactions</cite></a>.</p>
    3508. 

  3508.         <hr />
    3509. 

  3509.       </li>
    3510. 

  3510. 

  3511.       <li>
    3512. 

  3512.         <a id="footer" name="footer"><strong>How can I attach a
    3513. 

  3513.         footer to my documents without using SSI?</strong></a> 
    3514. 

  3514. 

  3515.         <p>You can make arbitrary changes to static documents by
    3516. 

  3516.         configuring an <a
    3517. 

  3517.         href="../mod/mod_actions.html#action">Action</a> which
    3518. 

  3518.         launches a CGI script. The CGI is then responsible for
    3519. 

  3519.         setting a content-type and delivering the requested
    3520. 

  3520.         document (the location of which is passed in the
    3521. 

  3521.         <samp>PATH_TRANSLATED</samp> environment variable), along
    3522. 

  3522.         with whatever footer is needed.</p>
    3523. 

  3523. 

  3524.         <p>Busy sites may not want to run a CGI script on every
    3525. 

  3525.         request, and should consider using an Apache module to add
    3526. 

  3526.         the footer. There are several third party modules available
    3527. 

  3527.         through the <a href="http://modules.apache.org/">Apache
    3528. 

  3528.         Module Registry</a> which will add footers to documents.
    3529. 

  3529.         These include mod_trailer, PHP
    3530. 

  3530.         (<samp>php3_auto_append_file</samp>), mod_layout, and
    3531. 

  3531.         mod_perl (<samp>Apache::Sandwich</samp>).</p>
    3532. 

  3532.         <hr />
    3533. 

  3533.       </li>
    3534. 

  3534. 

  3535.       <li>
    3536. 

  3536.         <a id="search" name="search"><strong>Does Apache include a
    3537. 

  3537.         search engine?</strong></a> 
    3538. 

  3538. 

  3539.         <p>Apache does not include a search engine, but there are
    3540. 

  3540.         many good commercial and free search engines which can be
    3541. 

  3541.         used easily with Apache. Some of them are listed on the <a
    3542. 

  3542.         href="http://www.searchtools.com/tools/tools.html">Web Site
    3543. 

  3543.         Search Tools</a> page. Open source search engines that are
    3544. 

  3544.         often used with Apache include <a
    3545. 

  3545.         href="http://www.htdig.org/">ht://Dig</a> and <a
    3546. 

  3546.         href="http://sunsite.berkeley.edu/SWISH-E/">SWISH-E</a>.</p>
    3547. 

  3547.         <hr />
    3548. 

  3548.       </li>
    3549. 

  3549. 

  3550.       <li>
    3551. 

  3551.         <a id="rotate" name="rotate"><strong>How can I rotate my
    3552. 

  3552.         log files?</strong></a> 
    3553. 

  3553. 

  3554.         <p>The simple answer: by piping the transfer log into an
    3555. 

  3555.         appropriate log file rotation utility.</p>
    3556. 

  3556. 

  3557.         <p>The longer answer: In the src/support/ directory, you
    3558. 

  3558.         will find a utility called <a
    3559. 

  3559.         href="../programs/rotatelogs.html">rotatelogs</a> which can
    3560. 

  3560.         be used like this:</p>
    3561. 

  3561. <pre>
    3562. 

  3562.    TransferLog "|/path/to/rotatelogs /path/to/logs/access_log 86400"
    3563. 

  3563. </pre>
    3564. 

  3564. 

  3565.         <p>to enable daily rotation of the log files.<br />
    3566. 

  3566.          A more sophisticated solution of a logfile rotation
    3567. 

  3567.         utility is available under the name <code>cronolog</code>
    3568. 

  3568.         from Andrew Ford's site at <a
    3569. 

  3569.         href="http://www.ford-mason.co.uk/resources/cronolog/">http://www.ford-mason.co.uk/resources/cronolog/</a>.
    3570. 

  3570.         It can automatically create logfile subdirectories based on
    3571. 

  3571.         time and date, and can have a constant symlink point to the
    3572. 

  3572.         rotating logfiles. (As of version 1.6.1, cronolog is
    3573. 

  3573.         available under the <a href="../LICENSE">Apache
    3574. 

  3574.         License</a>). Use it like this:</p>
    3575. 

  3575. <pre>
    3576. 

  3576.    CustomLog "|/path/to/cronolog --symlink=/usr/local/apache/logs/access_log /usr/local/apache/logs/%Y/%m/access_log" combined
    3577. 

  3577. </pre>
    3578. 

  3578.         <hr />
    3579. 

  3579.       </li>
    3580. 

  3580. 

  3581.       <li>
    3582. 

  3582.         <a id="conditional-logging"
    3583. 

  3583.         name="conditional-logging"><strong>How do I keep certain
    3584. 

  3584.         requests from appearing in my logs?</strong></a> 
    3585. 

  3585. 

  3586.         <p>The maximum flexibility for removing unwanted
    3587. 

  3587.         information from log files is obtained by post-processing
    3588. 

  3588.         the logs, or using piped-logs to feed the logs through a
    3589. 

  3589.         program which does whatever you want. However, Apache does
    3590. 

  3590.         offer the ability to prevent requests from ever appearing
    3591. 

  3591.         in the log files. You can do this by using the <a
    3592. 

  3592.         href="../mod/mod_setenvif.html#SetEnvIf"><code>SetEnvIf</code></a>
    3593. 

  3593.         directive to set an environment variable for certain
    3594. 

  3594.         requests and then using the conditional <a
    3595. 

  3595.         href="../mod/mod_log_config.html#customlog-conditional"><code>
    3596. 

  3596.         CustomLog</code></a> syntax to prevent logging when the
    3597. 

  3597.         environment variable is set.</p>
    3598. 

  3598.         <hr />
    3599. 

  3599.       </li>
    3600. 

  3600. 

  3601.       <li>
    3602. 

  3602.         <a id="dbinteg" name="dbinteg"><b>Does Apache support any
    3603. 

  3603.         sort of database integration?</b></a> 
    3604. 

  3604. 

  3605.         <p>No. Apache is a Web (HTTP) server, not an application
    3606. 

  3606.         server. The base package does not include any such
    3607. 

  3607.         functionality. See the <a href="http://www.php.net/">PHP
    3608. 

  3608.         project</a> and the <a
    3609. 

  3609.         href="http://perl.apache.org/">mod_perl project</a> for
    3610. 

  3610.         examples of modules that allow you to work with databases
    3611. 

  3611.         from within the Apache environment.</p>
    3612. 

  3612.         <hr />
    3613. 

  3613.       </li>
    3614. 

  3614. 

  3615.       <li>
    3616. 

  3616.         <a id="asp" name="asp"><b>Can I use Active Server Pages
    3617. 

  3617.         (ASP) with Apache?</b></a> 
    3618. 

  3618. 

  3619.         <p>The base Apache Web server package does not include ASP
    3620. 

  3620.         support. However, there are a couple of after-market
    3621. 

  3621.         solutions that let you add this functionality; see the <a
    3622. 

  3622.         href="http://httpd.apache.org/related_projects.html">related
    3623. 

  3623.         projects</a> page to find out more.</p>
    3624. 

  3624.         <hr />
    3625. 

  3625.       </li>
    3626. 

  3626. 

  3627.       <li>
    3628. 

  3628.         <a id="java" name="java"><b>Does Apache come with Java
    3629. 

  3629.         support?</b></a> 
    3630. 

  3630. 

  3631.         <p>The base Apache Web server package does not include
    3632. 

  3632.         support for Java, Java Server Pages, Enterprise Java Beans,
    3633. 

  3633.         or Java servlets. Those features are available as add-ons
    3634. 

  3634.         from the Apache/Java project site, &lt;URL:<a
    3635. 

  3635.         href="http://jakarta.apache.org">http://jakarta.apache.org/</a>&gt;.</p>
    3636. 

  3636.         <hr />
    3637. 

  3637.       </li>
    3638. 

  3638.     </ol>
    3639. 

  3639.     
    3640. 

  3640.     
    3641. 

  3641.   </body>
    3642. 

  3642. </html>
    3643. 

  3643. 

  3644. 

  3645.         <hr />
    3646. 

  3646. 

  3647.     <h3 align="CENTER">Apache HTTP Server Version 1.3</h3>
    3648. 

  3648.     <a href="./"><img src="../images/index.gif" alt="Index" /></a>
    3649. 

  3649.     <a href="../"><img src="../images/home.gif" alt="Home" /></a>
    3650. 

  3650. 

  3651.   </body>
    3652. 

  3652. </html>
    3653. 

  3653. 

  3654.