1<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 2 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3 4<html xmlns="http://www.w3.org/1999/xhtml"> 5 <head> 6 <meta name="generator" content="HTML Tidy, see www.w3.org" /> 7 8 <title>Apache module mod_proxy</title> 9 </head> 10 <!-- Background white, links blue (unvisited), navy (visited), red (active) --> 11 12 <body bgcolor="#FFFFFF" text="#000000" link="#0000FF" 13 vlink="#000080" alink="#FF0000"> 14 <div align="CENTER"> 15 <img src="../images/sub.gif" alt="[APACHE DOCUMENTATION]" /> 16 17 <h3>Apache HTTP Server Version 1.3</h3> 18 </div> 19 20 21 <h1 align="CENTER">Apache module mod_proxy</h1> 22 23 <p>This module provides for an <strong>HTTP 1.1</strong> 24 caching proxy server.</p> 25 26 <p><a href="module-dict.html#Status" 27 rel="Help"><strong>Status:</strong></a> Extension<br /> 28 <a href="module-dict.html#SourceFile" 29 rel="Help"><strong>Source File:</strong></a> mod_proxy.c<br /> 30 <a href="module-dict.html#ModuleIdentifier" 31 rel="Help"><strong>Module Identifier:</strong></a> 32 proxy_module<br /> 33 <a href="module-dict.html#Compatibility" 34 rel="Help"><strong>Compatibility:</strong></a> Available in 35 Apache 1.1 and later.</p> 36 37 <h2>Summary</h2> 38 This module implements a proxy/cache for Apache. It implements 39 proxying capability for <code>FTP</code>, <code>CONNECT</code> 40 (for SSL), <code>HTTP/0.9</code>, <code>HTTP/1.0</code>, and 41 (as of Apache 1.3.23) <code>HTTP/1.1</code>. 42 The module can be configured to connect to other proxy modules 43 for these and other protocols. 44 45 <p>This module was experimental in Apache 1.1.x. As of Apache 46 1.2, mod_proxy stability is <em>greatly</em> improved.</p> 47 48 <p><strong>Warning:</strong> Do not enable proxying with <a 49 href="#proxyrequests">ProxyRequests</a> until you have <a 50 href="#access">secured your server</a>. Open proxy servers are 51 dangerous both to your network and to the Internet at large.</p> 52 53 <h2>Directives</h2> 54 55 <ul> 56 <li><a href="#proxyrequests">ProxyRequests</a></li> 57 58 <li><a href="#proxyremote">ProxyRemote</a></li> 59 60 <li><a href="#proxypass">ProxyPass</a></li> 61 62 <li><a href="#proxypassreverse">ProxyPassReverse</a></li> 63 64 <li><a href="#proxypreservehost">ProxyPreserveHost</a></li> 65 66 <li><a href="#proxyblock">ProxyBlock</a></li> 67 68 <li><a href="#allowconnect">AllowCONNECT</a></li> 69 70 <li><a href="#proxyreceivebuffersize">ProxyReceiveBufferSize</a></li> 71 72 <li><a href="#proxyiobuffersize">ProxyIOBufferSize</a></li> 73 74 <li><a href="#noproxy">NoProxy</a></li> 75 76 <li><a href="#proxydomain">ProxyDomain</a></li> 77 78 <li><a href="#proxyvia">ProxyVia</a></li> 79 80 <li><a href="#cacheroot">CacheRoot</a></li> 81 82 <li><a href="#cachesize">CacheSize</a></li> 83 84 <li><a href="#cachemaxexpire">CacheMaxExpire</a></li> 85 86 <li><a href="#cachedefaultexpire">CacheDefaultExpire</a></li> 87 88 <li><a 89 href="#cachelastmodifiedfactor">CacheLastModifiedFactor</a></li> 90 91 <li><a href="#cachegcinterval">CacheGcInterval</a></li> 92 93 <li><a href="#cachedirlevels">CacheDirLevels</a></li> 94 95 <li><a href="#cachedirlength">CacheDirLength</a></li> 96 97 <li><a 98 href="#cacheforcecompletion">CacheForceCompletion</a></li> 99 100 <li><a href="#nocache">NoCache</a></li> 101 </ul> 102 103 <h2><a id="configs" name="configs">Common configuration 104 topics</a></h2> 105 106 <ul> 107 <li><a href="#forwardreverse">Forward and Reverse Proxies</a></li> 108 109 <li><a href="#examples">Basic Examples</a></li> 110 111 <li><a href="#access">Controlling access to your 112 proxy</a></li> 113 114 <li><a href="#shortname">Using Netscape hostname 115 shortcuts</a></li> 116 117 <li><a href="#mimetypes">Why doesn't file type <em>xxx</em> 118 download via FTP?</a></li> 119 120 <li><a href="#type">How can I force an FTP ASCII 121 download of File <em>xxx</em>?</a></li> 122 123 <li><a href="#percent2fhack">How can I access 124 FTP files outside of my home directory?</a></li> 125 126 <li><a href="#ftppass">How can I hide the 127 FTP cleartext password in my browser's URL line?</a></li> 128 129 <li><a href="#startup">Why does Apache start more slowly when 130 using the proxy module?</a></li> 131 132 <li><a href="#socks">Can I use the Apache proxy module with 133 my SOCKS proxy?</a></li> 134 135 <li><a href="#intranet">What other functions are useful for 136 an intranet proxy server?</a></li> 137 </ul> 138 139<h2><a name="forwardreverse" id="forwardreverse">Forward and Reverse Proxies</a></h2> 140 <p>Apache can be configured in both a <dfn>forward</dfn> and 141 <dfn>reverse</dfn> proxy mode.</p> 142 143 <p>An ordinary <dfn>forward proxy</dfn> is an intermediate 144 server that sits between the client and the <em>origin 145 server</em>. In order to get content from the origin server, 146 the client sends a request to the proxy naming the origin server 147 as the target and the proxy then requests the content from the 148 origin server and returns it to the client. The client must be 149 specially configured to use the forward proxy to access other 150 sites.</p> 151 152 <p>A typical usage of a forward proxy is to provide Internet 153 access to internal clients that are otherwise restricted by a 154 firewall. The forward proxy can also use caching to reduce 155 network usage.</p> 156 157 <p>The forward proxy is activated using the <code><a 158 href="#proxyrequests">ProxyRequests</a></code> directive. 159 Because forward proxys allow clients to access arbitrary sites 160 through your server and to hide their true origin, it is 161 essential that you <a href="#access">secure your server</a> so 162 that only authorized clients can access the proxy before 163 activating a forward proxy.</p> 164 165 <p>A <dfn>reverse proxy</dfn>, by contrast, appears to the 166 client just like an ordinary web server. No special 167 configuration on the client is necessary. The client makes 168 ordinary requests for content in the name-space of the reverse 169 proxy. The reverse proxy then decides where to send those 170 requests, and returns the content as if it was itself the 171 origin.</p> 172 173 <p>A typical usage of a reverse proxy is to provide Internet 174 users access to a server that is behind a firewall. Reverse 175 proxies can also be used to balance load among several back-end 176 servers, or to provide caching for a slower back-end server. 177 In addition, reverse proxies can be used simply to bring 178 several servers into the same URL space.</p> 179 180 <p>A reverse proxy is activated using the <code><a 181 href="#proxypass">ProxyPass</a></code> directive or the 182 <code>[P]</code> flag to the <code><a 183 href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> 184 directive. It is <strong>not</strong> necessary to turn 185 <code><a href="#proxyrequests">ProxyRequests</a></code> on in 186 order to configure a reverse proxy.</p> 187 188<h2><a name="examples" id="examples">Basic Examples</a></h2> 189 190 <p>The examples below are only a very basic idea to help you 191 get started. Please read the documentation on the individual 192 directives.</p> 193 194 <h3>Forward Proxy</h3><p><code> 195 ProxyRequests On<br /> 196 ProxyVia On<br /> 197 <br /> 198 <Directory proxy:*><br /> 199 200 Order deny,allow<br /> 201 Deny from all<br /> 202 Allow from internal.example.com<br /> 203 204 </Directory><br /> 205 <br /> 206 CacheRoot "/usr/local/apache/proxy"<br /> 207 CacheSize 5<br /> 208 CacheGcInterval 4<br /> 209 CacheMaxExpire 24<br /> 210 CacheLastModifiedFactor 0.1<br /> 211 CacheDefaultExpire 1<br /> 212 NoCache a-domain.com another-domain.edu joes.garage-sale.com 213 </code></p> 214 215 <h3>Reverse Proxy</h3><p><code> 216 ProxyRequests Off<br /> 217 <br /> 218 ProxyPass /foo http://foo.example.com/bar<br /> 219 ProxyPassReverse /foo http://foo.example.com/bar 220 </code></p> 221 222 <h2><a id="access" name="access">Controlling access to your 223 proxy</a></h2> 224 You can control who can access your proxy via the normal 225 <Directory> control block using the following example: 226<pre> 227<Directory proxy:*> 228Order Deny,Allow 229Deny from all 230Allow from yournetwork.example.com 231</Directory> 232</pre> 233 234 <p>A <Files> block will also work, and is the only method 235 known to work for all possible URLs in Apache versions earlier 236 than 1.2b10.</p> 237 238 <p>For more information, see <a 239 href="mod_access.html">mod_access</a>.</p> 240 241 <p>Strictly limiting access is essential if you are using a 242 forward proxy (using the <code><a 243 href="#proxyrequests">ProxyRequests</a></code> directive). 244 Otherwise, your server can be used by any client to access 245 arbitrary hosts while hiding his or her true identity. This is 246 dangerous both for your network and for the Internet at large. 247 When using a reverse proxy (using the <code><a 248 href="#proxypass">ProxyPass</a></code> directive with 249 <code>ProxyRequests Off</code>), access control is less critical 250 because clients can only contact the hosts that you have 251 specifically configured.</p> 252 253 <h2><a id="shortname" name="shortname">Using Netscape hostname 254 shortcuts</a></h2> 255 There is an optional patch to the proxy module to allow 256 Netscape-like hostname shortcuts to be used. It's available 257 from the <a 258 href="http://www.apache.org/dist/httpd/contrib/patches/1.2/netscapehost.patch"> 259 <samp>contrib/patches/1.2</samp></a> directory on the Apache 260 Web site. 261 262 <h2><a id="mimetypes" name="mimetypes">Why doesn't file type 263 <em>xxx</em> download via FTP?</a></h2> 264 You probably don't have that particular file type defined as 265 <em>application/octet-stream</em> in your proxy's mime.types 266 configuration file. A useful line can be 267<pre> 268application/octet-stream bin dms lha lzh exe class tgz taz 269</pre> 270 271 <h2><a id="type" name="type">How can I force an FTP ASCII 272 download of File <em>xxx</em>?</a></h2> 273 In the rare situation where you must download a specific file 274 using the FTP <strong>ASCII</strong> transfer method (while the 275 default transfer is in <strong>binary</strong> mode), you can 276 override mod_proxy's default by suffixing the request with 277 <samp>;type=a</samp> to force an ASCII transfer. 278 (FTP Directory listings are always executed in ASCII mode, however.) 279 280 <h2><a id="percent2fhack" name="percent2fhack">How can I access 281 FTP files outside of my home directory?</a></h2> 282 <p> 283 A FTP URI is interpreted relative to the home directory of 284 the user who is logging in. Alas, to reach higher directory 285 levels you cannot use /../, as the dots are interpreted by the 286 browser and not actually sent to the FTP server. To address 287 this problem, the so called "Squid %2f hack" was implemented in 288 the Apache FTP proxy; it is a solution which is also used by 289 other popular proxy servers like the 290 <a href="http://www.squid-cache.org/">Squid Proxy Cache</a>. 291 By prepending /%2f to the path of your request, you can make 292 such a proxy change the FTP starting directory to / (instead 293 of the home directory). <br /> 294 <b>Example:</b> To retrieve the file <code>/etc/motd</code>, 295 you would use the URL <blockquote> 296 <code>ftp://<em>user@host</em>/%2f/etc/motd</code></blockquote> 297 </p> 298 299 <h2><a id="ftppass" name="ftppass">How can I hide the FTP 300 cleartext password in my browser's URL line?</a></h2> 301 <p> 302 To log in to an FTP server by username and password, Apache 303 uses different strategies. 304 In absense of a user name and password in the URL altogether, 305 Apache sends an anonymous login to the FTP server, i.e., 306 <blockquote><code> 307 user: anonymous<br /> 308 password: apache_proxy@ 309 </code></blockquote> 310 This works for all popular FTP servers which are configured for 311 anonymous access.<br> 312 For a personal login with a specific username, you can embed 313 the user name into the URL, like in: 314 <code>ftp://<em>username@host</em>/myfile</code>. If the FTP server 315 asks for a password when given this username (which it should), 316 then Apache will reply with a [401 Authorization required] response, 317 which causes the Browser to pop up the username/password dialog. 318 Upon entering the password, the connection attempt is retried, 319 and if successful, the requested resource is presented. 320 The advantage of this procedure is that your browser does not 321 display the password in cleartext (which it would if you had used 322 <code>ftp://<em>username:password@host</em>/myfile</code> in 323 the first place). 324 <br /> 325 <b>Note</b> that the password which is transmitted in such a way 326 is not encrypted on its way. It travels between your browser and 327 the Apache proxy server in a base64-encoded cleartext string, and 328 between the Apache proxy and the FTP server as plaintext. You should 329 therefore think twice before accessing your FTP server via HTTP 330 (or before accessing your personal files via FTP at all!) When 331 using unsecure channels, an eavesdropper might intercept your 332 password on its way. 333 </p> 334 335 336 <h2><a id="startup" name="startup">Why does Apache start more 337 slowly when using the proxy module?</a></h2> 338 If you're using the <code>ProxyBlock</code> or 339 <code>NoCache</code> directives, hostnames' IP addresses are 340 looked up and cached during startup for later match test. This 341 may take a few seconds (or more) depending on the speed with 342 which the hostname lookups occur. 343 344 <h2><a id="socks" name="socks">Can I use the Apache proxy 345 module with my SOCKS proxy?</a></h2> 346 Yes. Just build Apache with the rule <code>SOCKS4=yes</code> in 347 your <em>Configuration</em> file, and follow the instructions 348 there. SOCKS5 capability can be added in a similar way (there's 349 no <code>SOCKS5</code> rule yet), so use the 350 <code>EXTRA_LDFLAGS</code> definition, or build Apache normally 351 and run it with the <em>runsocks</em> wrapper provided with 352 SOCKS5, if your OS supports dynamically linked libraries. 353 354 <p>Some users have reported problems when using SOCKS version 355 4.2 on Solaris. The problem was solved by upgrading to SOCKS 356 4.3.</p> 357 358 <p>Remember that you'll also have to grant access to your 359 Apache proxy machine by permitting connections on the 360 appropriate ports in your SOCKS daemon's configuration.</p> 361 362 <h2><a id="intranet" name="intranet">What other functions are 363 useful for an intranet proxy server?</a></h2> 364 365 <p>An Apache proxy server situated in an intranet needs to 366 forward external requests through the company's firewall 367 (for this, configure the <a href="#proxyremote">ProxyRemote</a> 368 directive to forward the respective <em>scheme</em> to 369 the firewall proxy). 370 However, when it has to access resources within the intranet, 371 it can bypass the firewall when accessing hosts. The <a 372 href="#noproxy">NoProxy</a> directive is useful for specifying 373 which hosts belong to the intranet and should be accessed 374 directly.</p> 375 376 <p>Users within an intranet tend to omit the local domain name 377 from their WWW requests, thus requesting "http://somehost/" 378 instead of "http://somehost.my.dom.ain/". Some commercial proxy 379 servers let them get away with this and simply serve the 380 request, implying a configured local domain. When the <a 381 href="#proxydomain">ProxyDomain</a> directive is used and the 382 server is <a href="#proxyrequests">configured for proxy 383 service</a>, Apache can return a redirect response and send the 384 client to the correct, fully qualified, server address. This is 385 the preferred method since the user's bookmark files will then 386 contain fully qualified hosts.</p> 387 <hr /> 388 389 <h2><a id="proxyrequests" 390 name="proxyrequests">ProxyRequests</a> directive</h2> 391 <a href="directive-dict.html#Syntax" 392 rel="Help"><strong>Syntax:</strong></a> ProxyRequests 393 on|off<br /> 394 <a href="directive-dict.html#Default" 395 rel="Help"><strong>Default:</strong></a> <code>ProxyRequests 396 Off</code><br /> 397 <a href="directive-dict.html#Context" 398 rel="Help"><strong>Context:</strong></a> server config, virtual 399 host<br /> 400 <a href="directive-dict.html#Override" 401 rel="Help"><strong>Override:</strong></a> <em>Not 402 applicable</em><br /> 403 <a href="directive-dict.html#Status" 404 rel="Help"><strong>Status:</strong></a> Base<br /> 405 <a href="directive-dict.html#Module" 406 rel="Help"><strong>Module:</strong></a> mod_proxy<br /> 407 <a href="directive-dict.html#Compatibility" 408 rel="Help"><strong>Compatibility:</strong></a> ProxyRequests is 409 only available in Apache 1.1 and later. 410 411 <p>This allows or prevents Apache from functioning as a forward proxy 412 server. Setting ProxyRequests to 'off' does not disable use of 413 the <a href="#proxypass">ProxyPass</a> directive.</p> 414 415 <p><strong>Warning:</strong> Do not enable proxying until you have 416 <a href="#access">secured your server</a>. Open proxy servers are 417 dangerous both to your network and to the Internet at large.</p> 418 419 <hr /> 420 421 <h2><a id="proxyremote" name="proxyremote">ProxyRemote</a> 422 directive</h2> 423 <a href="directive-dict.html#Syntax" 424 rel="Help"><strong>Syntax:</strong></a> ProxyRemote <em>match 425 remote-server</em><br /> 426 <a href="directive-dict.html#Default" 427 rel="Help"><strong>Default:</strong></a> <em>None</em><br /> 428 <a href="directive-dict.html#Context" 429 rel="Help"><strong>Context:</strong></a> server config, virtual 430 host<br /> 431 <a href="directive-dict.html#Override" 432 rel="Help"><strong>Override:</strong></a> <em>Not 433 applicable</em><br /> 434 <a href="directive-dict.html#Status" 435 rel="Help"><strong>Status:</strong></a> Base<br /> 436 <a href="directive-dict.html#Module" 437 rel="Help"><strong>Module:</strong></a> mod_proxy<br /> 438 <a href="directive-dict.html#Compatibility" 439 rel="Help"><strong>Compatibility:</strong></a> ProxyRemote is 440 only available in Apache 1.1 and later. 441 442 <p>This defines remote proxies to this proxy. <em>match</em> is 443 either the name of a URL-scheme that the remote server 444 supports, or a partial URL for which the remote server should 445 be used, or '*' to indicate the server should be contacted for 446 all requests. <em>remote-server</em> is a partial URL for the 447 remote server. Syntax:</p> 448<pre> 449 remote-server = protocol://hostname[:port] 450</pre> 451 <em>protocol</em> is the protocol that should be used to 452 communicate with the remote server; only "http" is supported by 453 this module. 454 455 <p>Example:</p> 456<pre> 457 ProxyRemote http://goodguys.com/ http://mirrorguys.com:8000 458 ProxyRemote * http://cleversite.com 459 ProxyRemote ftp http://ftpproxy.mydomain.com:8080 460</pre> 461 In the last example, the proxy will forward FTP requests, 462 encapsulated as yet another HTTP proxy request, to another 463 proxy which can handle them. 464 <hr /> 465 466 <h2><a id="proxypass" name="proxypass">ProxyPass</a> 467 directive</h2> 468 <a href="directive-dict.html#Syntax" 469 rel="Help"><strong>Syntax:</strong></a> ProxyPass <em>path 470 url</em><br /> 471 <a href="directive-dict.html#Default" 472 rel="Help"><strong>Default:</strong></a> <em>None</em><br /> 473 <a href="directive-dict.html#Context" 474 rel="Help"><strong>Context:</strong></a> server config, virtual 475 host<br /> 476 <a href="directive-dict.html#Override" 477 rel="Help"><strong>Override:</strong></a> <em>Not 478 applicable</em><br /> 479 <a href="directive-dict.html#Status" 480 rel="Help"><strong>Status:</strong></a> Base<br /> 481 <a href="directive-dict.html#Module" 482 rel="Help"><strong>Module:</strong></a> mod_proxy<br /> 483 <a href="directive-dict.html#Compatibility" 484 rel="Help"><strong>Compatibility:</strong></a> ProxyPass is 485 only available in Apache 1.1 and later. 486 487 <p>This directive allows remote servers to be mapped into the 488 space of the local server; the local server does not act as a 489 proxy in the conventional sense, but appears to be a mirror of 490 the remote server. <em>path</em> is the name of a local virtual 491 path; <em>url</em> is a partial URL for the remote server.</p> 492 493 <p>Suppose the local server has address 494 <samp>http://wibble.org/</samp>; then</p> 495<pre> 496 ProxyPass /mirror/foo/ http://foo.com/ 497</pre> 498 <p>will cause a local request for the 499 <<samp>http://wibble.org/mirror/foo/bar</samp>> to be 500 internally converted into a proxy request to 501 <<samp>http://foo.com/bar</samp>>.</p> 502 503 <p><strong>Warning:</strong> The <code><a 504 href="#proxyrequests">ProxyRequests</a></code> directive should 505 usually be set <strong>off</strong> when using <code 506 class="directive">ProxyPass</code>. 507 508 <hr /> 509 510 <h2><a id="proxypassreverse" 511 name="proxypassreverse">ProxyPassReverse</a> directive</h2> 512 <a href="directive-dict.html#Syntax" 513 rel="Help"><strong>Syntax:</strong></a> ProxyPassReverse 514 <em>path url</em><br /> 515 <a href="directive-dict.html#Default" 516 rel="Help"><strong>Default:</strong></a> <em>None</em><br /> 517 <a href="directive-dict.html#Context" 518 rel="Help"><strong>Context:</strong></a> server config, virtual 519 host<br /> 520 <a href="directive-dict.html#Override" 521 rel="Help"><strong>Override:</strong></a> <em>Not 522 applicable</em><br /> 523 <a href="directive-dict.html#Status" 524 rel="Help"><strong>Status:</strong></a> Base<br /> 525 <a href="directive-dict.html#Module" 526 rel="Help"><strong>Module:</strong></a> mod_proxy<br /> 527 <a href="directive-dict.html#Compatibility" 528 rel="Help"><strong>Compatibility:</strong></a> ProxyPassReverse 529 is only available in Apache 1.3b6 and later. 530 531 <p>This directive lets Apache adjust the URL in the 532 <tt>Location</tt> header on HTTP redirect responses. For 533 instance this is essential when Apache is used as a reverse 534 proxy to avoid by-passing the reverse proxy because of HTTP 535 redirects on the backend servers which stay behind the reverse 536 proxy.</p> 537 538 <p><em>path</em> is the name of a local virtual path.<br /> 539 <em>url</em> is a partial URL for the remote server - the same 540 way they are used for the <tt>ProxyPass</tt> directive.</p> 541 542 <p>Example:<br /> 543 Suppose the local server has address 544 <samp>http://wibble.org/</samp>; then</p> 545<pre> 546 ProxyPass /mirror/foo/ http://foo.com/ 547 ProxyPassReverse /mirror/foo/ http://foo.com/ 548</pre> 549 will not only cause a local request for the 550 <<samp>http://wibble.org/mirror/foo/bar</samp>> to be 551 internally converted into a proxy request to 552 <<samp>http://foo.com/bar</samp>> (the functionality 553 <samp>ProxyPass</samp> provides here). It also takes care of 554 redirects the server foo.com sends: when 555 <samp>http://foo.com/bar</samp> is redirected by him to 556 <samp>http://foo.com/quux</samp> Apache adjusts this to 557 <samp>http://wibble.org/mirror/foo/quux</samp> before 558 forwarding the HTTP redirect response to the client. 559 560 <p>Note that this <samp>ProxyPassReverse</samp> directive can 561 also be used in conjunction with the proxy pass-through feature 562 ("<samp>RewriteRule ... [P]</samp>") from <a 563 href="mod_rewrite.html#RewriteRule"><tt>mod_rewrite</tt></a> 564 because its doesn't depend on a corresponding 565 <samp>ProxyPass</samp> directive.</p> 566 <hr /> 567 568 <h2><a id="proxypreservehost" 569 name="proxypreservehost">ProxyPreserveHost</a> directive</h2> 570 <a href="directive-dict.html#Syntax" 571 rel="Help"><strong>Syntax:</strong></a> ProxyPreserveHost 572 <em>on|off</em><br /> 573 <a href="directive-dict.html#Default" 574 rel="Help"><strong>Default:</strong></a> 575 <em><samp>ProxyPreserveHost</samp> off</em><br /> 576 <a href="directive-dict.html#Context" 577 rel="Help"><strong>Context:</strong></a> server config, virtual 578 host<br /> 579 <a href="directive-dict.html#Override" 580 rel="Help"><strong>Override:</strong></a> <em>Not 581 applicable</em><br /> 582 <a href="directive-dict.html#Status" 583 rel="Help"><strong>Status:</strong></a> Base<br /> 584 <a href="directive-dict.html#Module" 585 rel="Help"><strong>Module:</strong></a> mod_proxy<br /> 586 587 <p>When enabled, this option will pass the Host: line from the 588 incoming request to the proxied host, instead of the hostname 589 specified in the proxypass line.<br /> 590 This option should normally be turned Off. It is mostly useful 591 in special configurations like proxied mass name-based virtual 592 hosting, where the original Host header needs to be evaluated by 593 the backend server.</p> 594 595 <h2><a id="allowconnect" name="allowconnect">AllowCONNECT</a> 596 directive</h2> 597 <a href="directive-dict.html#Syntax" 598 rel="Help"><strong>Syntax:</strong></a> AllowCONNECT 599 <em>port</em> [<em>port</em>] ...<br /> 600 <a href="directive-dict.html#Default" 601 rel="Help"><strong>Default:</strong></a> 602 <em><samp>AllowCONNECT</samp> 443 563</em><br /> 603 <a href="directive-dict.html#Context" 604 rel="Help"><strong>Context:</strong></a> server config, virtual 605 host<br /> 606 <a href="directive-dict.html#Override" 607 rel="Help"><strong>Override:</strong></a> <em>Not 608 applicable</em><br /> 609 <a href="directive-dict.html#Status" 610 rel="Help"><strong>Status:</strong></a> Base<br /> 611 <a href="directive-dict.html#Module" 612 rel="Help"><strong>Module:</strong></a> mod_proxy<br /> 613 <a href="directive-dict.html#Compatibility" 614 rel="Help"><strong>Compatibility:</strong></a> 615 <samp>AllowCONNECT</samp> is only available in Apache 1.3.2 and 616 later. 617 618 <p>The <samp>AllowCONNECT</samp> directive specifies a list of 619 port numbers to which the proxy <samp>CONNECT</samp> method may 620 connect. Today's browsers use this method when a <em>https</em> 621 connection is requested and proxy tunneling over <em>http</em> 622 is in effect.<br /> 623 By default, only the default https port (443) and the default 624 snews port (563) are enabled. Use the <samp>AllowCONNECT</samp> 625 directive to override this default and allow connections to 626 the listed ports only.</p> 627 <hr /> 628 629 <h2><a id="proxyblock" name="proxyblock">ProxyBlock</a> 630 directive</h2> 631 <a href="directive-dict.html#Syntax" 632 rel="Help"><strong>Syntax:</strong></a> ProxyBlock 633 *|<em>word|host|domain</em> [<em>word|host|domain</em>] 634 ...<br /> 635 <a href="directive-dict.html#Default" 636 rel="Help"><strong>Default:</strong></a> <em>None</em><br /> 637 <a href="directive-dict.html#Context" 638 rel="Help"><strong>Context:</strong></a> server config, virtual 639 host<br /> 640 <a href="directive-dict.html#Override" 641 rel="Help"><strong>Override:</strong></a> <em>Not 642 applicable</em><br /> 643 <a href="directive-dict.html#Status" 644 rel="Help"><strong>Status:</strong></a> Base<br /> 645 <a href="directive-dict.html#Module" 646 rel="Help"><strong>Module:</strong></a> mod_proxy<br /> 647 <a href="directive-dict.html#Compatibility" 648 rel="Help"><strong>Compatibility:</strong></a> ProxyBlock is 649 only available in Apache 1.2 and later. 650 651 <p>The ProxyBlock directive specifies a list of words, hosts 652 and/or domains, separated by spaces. HTTP, HTTPS, and FTP 653 document requests to sites whose names contain matched words, 654 hosts or domains are <em>blocked</em> by the proxy server. The 655 proxy module will also attempt to determine IP addresses of 656 list items which may be hostnames during startup, and cache 657 them for match test as well. Example:</p> 658<pre> 659 ProxyBlock joes-garage.com some-host.co.uk rocky.wotsamattau.edu 660</pre> 661 'rocky.wotsamattau.edu' would also be matched if referenced by 662 IP address. 663 664 <p>Note that 'wotsamattau' would also be sufficient to match 665 'wotsamattau.edu'.</p> 666 667 <p>Note also that</p> 668<pre> 669ProxyBlock * 670</pre> 671 blocks connections to all sites. 672 <hr /> 673 674 <h2><a id="proxyreceivebuffersize" 675 name="proxyreceivebuffersize">ProxyReceiveBufferSize</a> 676 directive</h2> 677 <a href="directive-dict.html#Syntax" 678 rel="Help"><strong>Syntax:</strong></a> ProxyReceiveBufferSize 679 <em>bytes</em><br /> 680 <a href="directive-dict.html#Default" 681 rel="Help"><strong>Default:</strong></a> <em>None</em><br /> 682 <a href="directive-dict.html#Context" 683 rel="Help"><strong>Context:</strong></a> server config, virtual 684 host<br /> 685 <a href="directive-dict.html#Override" 686 rel="Help"><strong>Override:</strong></a> <em>Not 687 applicable</em><br /> 688 <a href="directive-dict.html#Status" 689 rel="Help"><strong>Status:</strong></a> Base<br /> 690 <a href="directive-dict.html#Module" 691 rel="Help"><strong>Module:</strong></a> mod_proxy<br /> 692 <a href="directive-dict.html#Compatibility" 693 rel="Help"><strong>Compatibility:</strong></a> 694 ProxyReceiveBufferSize is only available in Apache 1.3 and 695 later. 696 697 <p>The ProxyReceiveBufferSize directive specifies an explicit 698 network buffer size for outgoing HTTP and FTP connections, for 699 increased throughput. It has to be greater than 512 or set to 0 700 to indicate that the system's default buffer size should be 701 used.</p> 702 703 <p>Example:</p> 704<pre> 705 ProxyReceiveBufferSize 2048 706</pre> 707 <hr /> 708 709 <h2><a id="proxyiobuffersize" 710 name="proxyiobuffersize">ProxyIOBufferSize</a> 711 directive</h2> 712 <a href="directive-dict.html#Syntax" 713 rel="Help"><strong>Syntax:</strong></a> ProxyIOBufferSize 714 <em>bytes</em><br /> 715 <a href="directive-dict.html#Default" 716 rel="Help"><strong>Default:</strong></a> <em>8192</em><br /> 717 <a href="directive-dict.html#Context" 718 rel="Help"><strong>Context:</strong></a> server config, virtual 719 host<br /> 720 <a href="directive-dict.html#Override" 721 rel="Help"><strong>Override:</strong></a> <em>Not 722 applicable</em><br /> 723 <a href="directive-dict.html#Status" 724 rel="Help"><strong>Status:</strong></a> Base<br /> 725 <a href="directive-dict.html#Module" 726 rel="Help"><strong>Module:</strong></a> mod_proxy<br /> 727 <a href="directive-dict.html#Compatibility" 728 rel="Help"><strong>Compatibility:</strong></a> 729 ProxyIOBufferSize is only available in Apache 1.3.24 and 730 later. 731 732 <p>The ProxyIOBufferSize directive specifies the number of bytes 733 that will be read from a remote HTTP or FTP server at one time. 734 This directive is different from the ProxyReceiveBufferSize 735 directive, which specifies the low level socket buffer size. 736 </p> 737 738 <p> 739 When a response is received which fits entirely within the IO 740 buffer size, the remote HTTP or FTP server socket will be closed 741 before an attempt is made to write the response to the client. 742 This ensures that the remote server does not remain connected 743 unnecessarily while the response is delivered to a slow client. 744 A high value for the IO buffer decreases the load on remote HTTP 745 and FTP servers, at the expense of greater RAM footprint on the 746 proxy. 747 </p> 748 749 <p>Example:</p> 750<pre> 751 ProxyIOBufferSize 131072 752</pre> 753 <hr /> 754 755 <h2><a id="noproxy" name="noproxy">NoProxy</a> directive</h2> 756 <a href="directive-dict.html#Syntax" 757 rel="Help"><strong>Syntax:</strong></a> NoProxy <a 758 href="#domain"><em>Domain</em></a>|<a 759 href="#subnet"><em>SubNet</em></a>|<a 760 href="#ipaddr"><em>IpAddr</em></a>|<a 761 href="#hostname"><em>Hostname</em></a> [<a 762 href="#domain"><em>Domain</em></a>|<a 763 href="#subnet"><em>SubNet</em></a>|<a 764 href="#ipaddr"><em>IpAddr</em></a>|<a 765 href="#hostname"><em>Hostname</em></a>] ...<br /> 766 <a href="directive-dict.html#Default" 767 rel="Help"><strong>Default:</strong></a> <em>None</em><br /> 768 <a href="directive-dict.html#Context" 769 rel="Help"><strong>Context:</strong></a> server config, virtual 770 host<br /> 771 <a href="directive-dict.html#Override" 772 rel="Help"><strong>Override:</strong></a> <em>Not 773 applicable</em><br /> 774 <a href="directive-dict.html#Status" 775 rel="Help"><strong>Status:</strong></a> Base<br /> 776 <a href="directive-dict.html#Module" 777 rel="Help"><strong>Module:</strong></a> mod_proxy<br /> 778 <a href="directive-dict.html#Compatibility" 779 rel="Help"><strong>Compatibility:</strong></a> NoProxy is only 780 available in Apache 1.3 and later. 781 782 <p>This directive is only useful for Apache proxy servers 783 within intranets. The NoProxy directive specifies a list of 784 subnets, IP addresses, hosts and/or domains, separated by 785 spaces. A request to a host which matches one or more of these 786 is always served directly, without forwarding to the configured 787 ProxyRemote proxy server(s).</p> 788 789 <p>Example:</p> 790<pre> 791 ProxyRemote * http://firewall.mycompany.com:81 792 NoProxy .mycompany.com 192.168.112.0/21 793</pre> 794 The arguments to the NoProxy directive are one of the following 795 type list: 796 797 <dl> 798 <!-- ===================== Domain ======================= --> 799 800 <dt><a id="domain" name="domain"><em>Domain</em></a></dt> 801 802 <dd>A <em>Domain</em> is a partially qualified DNS domain 803 name, preceded by a period. It represents a list of hosts 804 which logically belong to the same DNS domain or zone 805 (<em>i.e.</em>, the suffixes of the hostnames are all ending 806 in <em>Domain</em>).<br /> 807 Examples: <samp>.com</samp> <samp>.apache.org.</samp><br /> 808 To distinguish <em>Domain</em>s from <a 809 href="#hostname"><em>Hostname</em></a>s (both syntactically 810 and semantically; a DNS domain can have a DNS A record, 811 too!), <em>Domain</em>s are always written with a leading 812 period.<br /> 813 Note: Domain name comparisons are done without regard to the 814 case, and <em>Domain</em>s are always assumed to be anchored 815 in the root of the DNS tree, therefore two domains 816 <samp>.MyDomain.com</samp> and <samp>.mydomain.com.</samp> 817 (note the trailing period) are considered equal. Since a 818 domain comparison does not involve a DNS lookup, it is much 819 more efficient than subnet comparison. 820 <!-- ===================== SubNet ======================= --> 821 </dd> 822 823 <dt><a id="subnet" name="subnet"><em>SubNet</em></a></dt> 824 825 <dd> 826 A <em>SubNet</em> is a partially qualified internet address 827 in numeric (dotted quad) form, optionally followed by a 828 slash and the netmask, specified as the number of 829 significant bits in the <em>SubNet</em>. It is used to 830 represent a subnet of hosts which can be reached over a 831 common network interface. In the absence of the explicit 832 net mask it is assumed that omitted (or zero valued) 833 trailing digits specify the mask. (In this case, the 834 netmask can only be multiples of 8 bits wide.)<br /> 835 Examples: 836 837 <dl> 838 <dt><samp>192.168</samp> or <samp>192.168.0.0</samp></dt> 839 840 <dd>the subnet 192.168.0.0 with an implied netmask of 16 841 valid bits (sometimes used in the netmask form 842 <samp>255.255.0.0</samp>)</dd> 843 844 <dt><samp>192.168.112.0/21</samp></dt> 845 846 <dd>the subnet <samp>192.168.112.0/21</samp> with a 847 netmask of 21 valid bits (also used in the form 848 255.255.248.0)</dd> 849 </dl> 850 As a degenerate case, a <em>SubNet</em> with 32 valid bits 851 is the equivalent to an <em>IPAddr</em>, while a 852 <em>SubNet</em> with zero valid bits (<em>e.g.</em>, 853 0.0.0.0/0) is the same as the constant <em>_Default_</em>, 854 matching any IP address. 855 <!-- ===================== IPAddr ======================= --> 856 </dd> 857 858 <dt><a id="ipaddr" name="ipaddr"><em>IPAddr</em></a></dt> 859 860 <dd> 861 A <em>IPAddr</em> represents a fully qualified internet 862 address in numeric (dotted quad) form. Usually, this 863 address represents a host, but there need not necessarily 864 be a DNS domain name connected with the address.<br /> 865 Example: 192.168.123.7<br /> 866 Note: An <em>IPAddr</em> does not need to be resolved by 867 the DNS system, so it can result in more effective apache 868 performance. 869 870 <p><strong>See Also:</strong> <a 871 href="../dns-caveats.html">DNS Issues</a></p> 872 <!-- ===================== Hostname ======================= --> 873 </dd> 874 875 <dt><a id="hostname" 876 name="hostname"><em>Hostname</em></a></dt> 877 878 <dd> 879 A <em>Hostname</em> is a fully qualified DNS domain name 880 which can be resolved to one or more <a 881 href="#ipaddr"><em>IPAddrs</em></a> via the DNS domain name 882 service. It represents a logical host (in contrast to <a 883 href="#domain"><em>Domain</em></a>s, see above) and must be 884 resolvable to at least one <a 885 href="#ipaddr"><em>IPAddr</em></a> (or often to a list of 886 hosts with different <a 887 href="#ipaddr"><em>IPAddr</em></a>'s).<br /> 888 Examples: <samp>prep.ai.mit.edu</samp> 889 <samp>www.apache.org.</samp><br /> 890 Note: In many situations, it is more effective to specify 891 an <a href="#ipaddr"><em>IPAddr</em></a> in place of a 892 <em>Hostname</em> since a DNS lookup can be avoided. Name 893 resolution in Apache can take a remarkable deal of time 894 when the connection to the name server uses a slow PPP 895 link.<br /> 896 Note: <em>Hostname</em> comparisons are done without 897 regard to the case, and <em>Hostname</em>s are always 898 assumed to be anchored in the root of the DNS tree, 899 therefore two hosts <samp>WWW.MyDomain.com</samp> and 900 <samp>www.mydomain.com.</samp> (note the trailing period) 901 are considered equal.<br /> 902 903 904 <p><strong>See Also:</strong> <a 905 href="../dns-caveats.html">DNS Issues</a></p> 906 </dd> 907 </dl> 908 <hr /> 909 910 <h2><a id="proxydomain" name="proxydomain">ProxyDomain</a> 911 directive</h2> 912 <a href="directive-dict.html#Syntax" 913 rel="Help"><strong>Syntax:</strong></a> ProxyDomain 914 <em>Domain</em><br /> 915 <a href="directive-dict.html#Default" 916 rel="Help"><strong>Default:</strong></a> <em>None</em><br /> 917 <a href="directive-dict.html#Context" 918 rel="Help"><strong>Context:</strong></a> server config, virtual 919 host<br /> 920 <a href="directive-dict.html#Override" 921 rel="Help"><strong>Override:</strong></a> <em>Not 922 applicable</em><br /> 923 <a href="directive-dict.html#Status" 924 rel="Help"><strong>Status:</strong></a> Base<br /> 925 <a href="directive-dict.html#Module" 926 rel="Help"><strong>Module:</strong></a> mod_proxy<br /> 927 <a href="directive-dict.html#Compatibility" 928 rel="Help"><strong>Compatibility:</strong></a> ProxyDomain is 929 only available in Apache 1.3 and later. 930 931 <p>This directive is only useful for Apache proxy servers 932 within intranets. The ProxyDomain directive specifies the 933 default domain which the apache proxy server will belong to. If 934 a request to a host without a domain name is encountered, a 935 redirection response to the same host with the configured 936 <em>Domain</em> appended will be generated.</p> 937 938 <p>Example:</p> 939<pre> 940 ProxyRemote * http://firewall.mycompany.com:81 941 NoProxy .mycompany.com 192.168.112.0/21 942 ProxyDomain .mycompany.com 943</pre> 944 <hr /> 945 946 <h2><a id="proxyvia" name="proxyvia">ProxyVia</a> 947 directive</h2> 948 <a href="directive-dict.html#Syntax" 949 rel="Help"><strong>Syntax:</strong></a> ProxyVia 950 on|off|full|block<br /> 951 <a href="directive-dict.html#Default" 952 rel="Help"><strong>Default:</strong></a> <em>ProxyVia 953 off</em><br /> 954 <a href="directive-dict.html#Context" 955 rel="Help"><strong>Context:</strong></a> server config, virtual 956 host<br /> 957 <a href="directive-dict.html#Override" 958 rel="Help"><strong>Override:</strong></a> <em>Not 959 applicable</em><br /> 960 <a href="directive-dict.html#Status" 961 rel="Help"><strong>Status:</strong></a> Base<br /> 962 <a href="directive-dict.html#Module" 963 rel="Help"><strong>Module:</strong></a> mod_proxy<br /> 964 <a href="directive-dict.html#Compatibility" 965 rel="Help"><strong>Compatibility:</strong></a> ProxyVia is only 966 available in Apache 1.3.2 and later. 967 968 <p>This directive controls the use of the <samp>Via:</samp> 969 HTTP header by the proxy. Its intended use is to control the 970 flow of of proxy requests along a chain of proxy servers. See 971 RFC2068 (HTTP/1.1) for an explanation of <samp>Via:</samp> 972 header lines.</p> 973 974 <ul> 975 <li>If set to <em>off</em>, which is the default, no special 976 processing is performed. If a request or reply contains a 977 <samp>Via:</samp> header, it is passed through 978 unchanged.</li> 979 980 <li>If set to <em>on</em>, each request and reply will get a 981 <samp>Via:</samp> header line added for the current 982 host.</li> 983 984 <li>If set to <em>full</em>, each generated <samp>Via:</samp> 985 header line will additionally have the Apache server version 986 shown as a <samp>Via:</samp> comment field.</li> 987 988 <li>If set to <em>block</em>, every proxy request will have 989 all its <samp>Via:</samp> header lines removed. No new 990 <samp>Via:</samp> header will be generated.</li> 991 </ul> 992 <hr /> 993 994 <h2><a id="cacheforcecompletion" 995 name="cacheforcecompletion">CacheForceCompletion</a> 996 directive</h2> 997 <a href="directive-dict.html#Syntax" 998 rel="Help"><strong>Syntax:</strong></a> CacheForceCompletion 999 <em>percentage</em><br /> 1000 <a href="directive-dict.html#Default" 1001 rel="Help"><strong>Default:</strong></a> <em>90</em><br /> 1002 <a href="directive-dict.html#Context" 1003 rel="Help"><strong>Context:</strong></a> server config, virtual 1004 host<br /> 1005 <a href="directive-dict.html#Override" 1006 rel="Help"><strong>Override:</strong></a> <em>Not 1007 applicable</em><br /> 1008 <a href="directive-dict.html#Status" 1009 rel="Help"><strong>Status:</strong></a> Base<br /> 1010 <a href="directive-dict.html#Module" 1011 rel="Help"><strong>Module:</strong></a> mod_proxy<br /> 1012 <a href="directive-dict.html#Compatibility" 1013 rel="Help"><strong>Compatibility:</strong></a> 1014 CacheForceCompletion is only available in Apache 1.3.1 and 1015 later. 1016 1017 <p>If an http transfer that is being cached is cancelled, the 1018 proxy module will complete the transfer to cache if more than 1019 the percentage specified has already been transferred.</p> 1020 1021 <p>This is a percentage, and must be a number between 1 and 1022 100, or 0 to use the default. 100 will cause a document to be 1023 cached only if the transfer was allowed to complete. A number 1024 between 60 and 90 is recommended.</p> 1025 <hr /> 1026 1027 <h2><a id="cacheroot" name="cacheroot">CacheRoot</a> 1028 directive</h2> 1029 <a href="directive-dict.html#Syntax" 1030 rel="Help"><strong>Syntax:</strong></a> CacheRoot 1031 <em>directory</em><br /> 1032 <a href="directive-dict.html#Default" 1033 rel="Help"><strong>Default:</strong></a> <em>None</em><br /> 1034 <a href="directive-dict.html#Context" 1035 rel="Help"><strong>Context:</strong></a> server config, virtual 1036 host<br /> 1037 <a href="directive-dict.html#Override" 1038 rel="Help"><strong>Override:</strong></a> <em>Not 1039 applicable</em><br /> 1040 <a href="directive-dict.html#Status" 1041 rel="Help"><strong>Status:</strong></a> Base<br /> 1042 <a href="directive-dict.html#Module" 1043 rel="Help"><strong>Module:</strong></a> mod_proxy<br /> 1044 <a href="directive-dict.html#Compatibility" 1045 rel="Help"><strong>Compatibility:</strong></a> CacheRoot is 1046 only available in Apache 1.1 and later. 1047 1048 <p>Sets the name of the directory to contain cache files; this 1049 must be writable by the httpd server. (see the <a 1050 href="core.html#user"><code>User</code></a> directive).<br /> 1051 Setting <code>CacheRoot</code> enables proxy cacheing; without 1052 defining a <code>CacheRoot</code>, proxy functionality will be 1053 available if <code>ProxyRequests</code> are set to 1054 <code>On</code>, but no cacheing will be available.</p> 1055 <hr /> 1056 1057 <h2><a id="cachesize" name="cachesize">CacheSize</a> 1058 directive</h2> 1059 <a href="directive-dict.html#Syntax" 1060 rel="Help"><strong>Syntax:</strong></a> CacheSize 1061 <em>kilobytes</em><br /> 1062 <a href="directive-dict.html#Default" 1063 rel="Help"><strong>Default:</strong></a> <code>CacheSize 1064 5</code><br /> 1065 <a href="directive-dict.html#Context" 1066 rel="Help"><strong>Context:</strong></a> server config, virtual 1067 host<br /> 1068 <a href="directive-dict.html#Override" 1069 rel="Help"><strong>Override:</strong></a> <em>Not 1070 applicable</em><br /> 1071 <a href="directive-dict.html#Status" 1072 rel="Help"><strong>Status:</strong></a> Base<br /> 1073 <a href="directive-dict.html#Module" 1074 rel="Help"><strong>Module:</strong></a> mod_proxy<br /> 1075 <a href="directive-dict.html#Compatibility" 1076 rel="Help"><strong>Compatibility:</strong></a> CacheSize is 1077 only available in Apache 1.1 and later. 1078 1079 <p>Sets the desired space usage of the cache, in KB (1024-byte 1080 units). Although usage may grow above this setting, the garbage 1081 collection will delete files until the usage is at or below 1082 this setting.<br /> 1083 Depending on the expected proxy traffic volume and 1084 <code>CacheGcInterval</code>, use a value which is at least 20 1085 to 40 % lower than the available space.</p> 1086 <hr /> 1087 1088 <h2><a id="cachegcinterval" 1089 name="cachegcinterval">CacheGcInterval</a> directive</h2> 1090 <a href="directive-dict.html#Syntax" 1091 rel="Help"><strong>Syntax:</strong></a> CacheGcInterval 1092 <em>hours</em><br /> 1093 <a href="directive-dict.html#Default" 1094 rel="Help"><strong>Default:</strong></a> <em>None</em><br /> 1095 <a href="directive-dict.html#Context" 1096 rel="Help"><strong>Context:</strong></a> server config, virtual 1097 host<br /> 1098 <a href="directive-dict.html#Override" 1099 rel="Help"><strong>Override:</strong></a> <em>Not 1100 applicable</em><br /> 1101 <a href="directive-dict.html#Status" 1102 rel="Help"><strong>Status:</strong></a> Base<br /> 1103 <a href="directive-dict.html#Module" 1104 rel="Help"><strong>Module:</strong></a> mod_proxy<br /> 1105 <a href="directive-dict.html#Compatibility" 1106 rel="Help"><strong>Compatibility:</strong></a> CacheGcinterval 1107 is only available in Apache 1.1 and later. 1108 1109 <p>Check the cache after the specified number of 1110 <em>hours</em>, and delete files if the space usage is greater 1111 than that set by CacheSize. Note that <em>hours</em> accepts a 1112 float value, you could for example use <code>CacheGcInterval 1113 1.5</code> to check the cache every 90 minutes. (If unset, no 1114 garbage collection will be performed, and the cache will grow 1115 indefinitely.) Note also that the larger the 1116 <code>CacheGcInterval</code>, the more extra space beyond the 1117 configured <code>CacheSize</code> will be needed for the cache 1118 between garbage collections.<br /> 1119 <!-- Note that due to a design flaw, Apache 1120 does not automatically force a garbage collection when the available 1121 space on the file system where the cache resides is exhausted. --> 1122 </p> 1123 <hr /> 1124 1125 <h2><a id="cachemaxexpire" 1126 name="cachemaxexpire">CacheMaxExpire</a> directive</h2> 1127 <a href="directive-dict.html#Syntax" 1128 rel="Help"><strong>Syntax:</strong></a> CacheMaxExpire 1129 <em>hours</em><br /> 1130 <a href="directive-dict.html#Default" 1131 rel="Help"><strong>Default:</strong></a> <code>CacheMaxExpire 1132 24</code><br /> 1133 <a href="directive-dict.html#Context" 1134 rel="Help"><strong>Context:</strong></a> server config, virtual 1135 host<br /> 1136 <a href="directive-dict.html#Override" 1137 rel="Help"><strong>Override:</strong></a> <em>Not 1138 applicable</em><br /> 1139 <a href="directive-dict.html#Status" 1140 rel="Help"><strong>Status:</strong></a> Base<br /> 1141 <a href="directive-dict.html#Module" 1142 rel="Help"><strong>Module:</strong></a> mod_proxy<br /> 1143 <a href="directive-dict.html#Compatibility" 1144 rel="Help"><strong>Compatibility:</strong></a> CacheMaxExpire 1145 is only available in Apache 1.1 and later. 1146 1147 <p>Specifies the maximum number of <em>hours</em> for which 1148 cachable HTTP documents will be retained without checking the 1149 origin server. Thus, documents will be out of date at most this 1150 number of <em>hours</em> This restriction is enforced even if 1151 an expiry date was supplied with the document.</p> 1152 <hr /> 1153 1154 <h2><a id="cachelastmodifiedfactor" 1155 name="cachelastmodifiedfactor">CacheLastModifiedFactor</a> 1156 directive</h2> 1157 <a href="directive-dict.html#Syntax" 1158 rel="Help"><strong>Syntax:</strong></a> CacheLastModifiedFactor 1159 <em>factor</em><br /> 1160 <a href="directive-dict.html#Default" 1161 rel="Help"><strong>Default:</strong></a> 1162 <code>CacheLastModifiedFactor 0.1</code><br /> 1163 <a href="directive-dict.html#Context" 1164 rel="Help"><strong>Context:</strong></a> server config, virtual 1165 host<br /> 1166 <a href="directive-dict.html#Override" 1167 rel="Help"><strong>Override:</strong></a> <em>Not 1168 applicable</em><br /> 1169 <a href="directive-dict.html#Status" 1170 rel="Help"><strong>Status:</strong></a> Base<br /> 1171 <a href="directive-dict.html#Module" 1172 rel="Help"><strong>Module:</strong></a> mod_proxy<br /> 1173 <a href="directive-dict.html#Compatibility" 1174 rel="Help"><strong>Compatibility:</strong></a> 1175 CacheLastModifiedFactor is only available in Apache 1.1 and 1176 later. 1177 1178 <p>If the origin HTTP server did not supply an expiry date for 1179 the document, then estimate one using the formula</p> 1180<pre> 1181 expiry-period = time-since-last-modification * <em>factor</em> 1182</pre> 1183 For example, if the document was last modified 10 hours ago, 1184 and <em>factor</em> is 0.1, then the expiry period will be set 1185 to 10*0.1 = 1 hour. 1186 1187 <p>If the expiry-period would be longer than that set by 1188 CacheMaxExpire, then the latter takes precedence.</p> 1189 <hr /> 1190 1191 <h2><a id="cachedirlevels" 1192 name="cachedirlevels">CacheDirLevels</a> directive</h2> 1193 <a href="directive-dict.html#Syntax" 1194 rel="Help"><strong>Syntax:</strong></a> CacheDirLevels 1195 <em>levels</em><br /> 1196 <a href="directive-dict.html#Default" 1197 rel="Help"><strong>Default:</strong></a> <code>CacheDirLevels 1198 3</code><br /> 1199 <a href="directive-dict.html#Context" 1200 rel="Help"><strong>Context:</strong></a> server config, virtual 1201 host<br /> 1202 <a href="directive-dict.html#Override" 1203 rel="Help"><strong>Override:</strong></a> <em>Not 1204 applicable</em><br /> 1205 <a href="directive-dict.html#Status" 1206 rel="Help"><strong>Status:</strong></a> Base<br /> 1207 <a href="directive-dict.html#Module" 1208 rel="Help"><strong>Module:</strong></a> mod_proxy<br /> 1209 <a href="directive-dict.html#Compatibility" 1210 rel="Help"><strong>Compatibility:</strong></a> CacheDirLevels 1211 is only available in Apache 1.1 and later. 1212 1213 <p>CacheDirLevels sets the number of <em>levels</em> of 1214 subdirectories in the cache. Cached data will be saved this 1215 many directory levels below CacheRoot.</p> 1216 <hr /> 1217 1218 <h2><a id="cachedirlength" 1219 name="cachedirlength">CacheDirLength</a> directive</h2> 1220 <a href="directive-dict.html#Syntax" 1221 rel="Help"><strong>Syntax:</strong></a> CacheDirLength 1222 <em>length</em><br /> 1223 <a href="directive-dict.html#Default" 1224 rel="Help"><strong>Default:</strong></a> <code>CacheDirLength 1225 1</code><br /> 1226 <a href="directive-dict.html#Context" 1227 rel="Help"><strong>Context:</strong></a> server config, virtual 1228 host<br /> 1229 <a href="directive-dict.html#Override" 1230 rel="Help"><strong>Override:</strong></a> <em>Not 1231 applicable</em><br /> 1232 <a href="directive-dict.html#Status" 1233 rel="Help"><strong>Status:</strong></a> Base<br /> 1234 <a href="directive-dict.html#Module" 1235 rel="Help"><strong>Module:</strong></a> mod_proxy<br /> 1236 <a href="directive-dict.html#Compatibility" 1237 rel="Help"><strong>Compatibility:</strong></a> CacheDirLength 1238 is only available in Apache 1.1 and later. 1239 1240 <p>CacheDirLength sets the number of characters in proxy cache 1241 subdirectory names.</p> 1242 <hr /> 1243 1244 <h2><a id="cachedefaultexpire" 1245 name="cachedefaultexpire">CacheDefaultExpire</a> directive</h2> 1246 <a href="directive-dict.html#Syntax" 1247 rel="Help"><strong>Syntax:</strong></a> CacheDefaultExpire 1248 <em>hours</em><br /> 1249 <a href="directive-dict.html#Default" 1250 rel="Help"><strong>Default:</strong></a> 1251 <code>CacheDefaultExpire 1</code><br /> 1252 <a href="directive-dict.html#Context" 1253 rel="Help"><strong>Context:</strong></a> server config, virtual 1254 host<br /> 1255 <a href="directive-dict.html#Override" 1256 rel="Help"><strong>Override:</strong></a> <em>Not 1257 applicable</em><br /> 1258 <a href="directive-dict.html#Status" 1259 rel="Help"><strong>Status:</strong></a> Base<br /> 1260 <a href="directive-dict.html#Module" 1261 rel="Help"><strong>Module:</strong></a> mod_proxy<br /> 1262 <a href="directive-dict.html#Compatibility" 1263 rel="Help"><strong>Compatibility:</strong></a> 1264 CacheDefaultExpire is only available in Apache 1.1 and later. 1265 1266 <p>If the document is fetched via a protocol that does not 1267 support expiry times, then use the specified number of 1268 <em>hours</em> as the expiry time. <a 1269 href="#cachemaxexpire">CacheMaxExpire</a> does 1270 <strong>not</strong> override this setting.</p> 1271 <hr /> 1272 1273 <h2><a id="nocache" name="nocache">NoCache</a> directive</h2> 1274 <a href="directive-dict.html#Syntax" 1275 rel="Help"><strong>Syntax:</strong></a> NoCache 1276 *|<em>word|host|domain</em> [<em>word|host|domain</em>] 1277 ...<br /> 1278 <a href="directive-dict.html#Default" 1279 rel="Help"><strong>Default:</strong></a> <em>None</em><br /> 1280 <a href="directive-dict.html#Context" 1281 rel="Help"><strong>Context:</strong></a> server config, virtual 1282 host<br /> 1283 <a href="directive-dict.html#Override" 1284 rel="Help"><strong>Override:</strong></a> <em>Not 1285 applicable</em><br /> 1286 <a href="directive-dict.html#Status" 1287 rel="Help"><strong>Status:</strong></a> Base<br /> 1288 <a href="directive-dict.html#Module" 1289 rel="Help"><strong>Module:</strong></a> mod_proxy<br /> 1290 <a href="directive-dict.html#Compatibility" 1291 rel="Help"><strong>Compatibility:</strong></a> NoCache is only 1292 available in Apache 1.1 and later. 1293 1294 <p>The NoCache directive specifies a list of words, hosts 1295 and/or domains, separated by spaces. HTTP and non-passworded 1296 FTP documents from matched words, hosts or domains are 1297 <em>not</em> cached by the proxy server. The proxy module will 1298 also attempt to determine IP addresses of list items which may 1299 be hostnames during startup, and cache them for match test as 1300 well. Example:</p> 1301<pre> 1302 NoCache joes-garage.com some-host.co.uk bullwinkle.wotsamattau.edu 1303</pre> 1304 'bullwinkle.wotsamattau.edu' would also be matched if 1305 referenced by IP address. 1306 1307 <p>Note that 'wotsamattau' would also be sufficient to match 1308 'wotsamattau.edu'.</p> 1309 1310 <p>Note also that</p> 1311<pre> 1312NoCache * 1313</pre> 1314 disables caching completely. 1315 1316 <p> <hr /> 1317 1318 <h3 align="CENTER">Apache HTTP Server Version 1.3</h3> 1319 <a href="./"><img src="../images/index.gif" alt="Index" /></a> 1320 <a href="../"><img src="../images/home.gif" alt="Home" /></a> 1321 1322 </p> 1323 </body> 1324</html> 1325 1326
