1 <?xml version="1.0" encoding="ISO-8859-1"?>
2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
3 <html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head><!--
4 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
5 This file is generated from xml source: DO NOT EDIT
6 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
8 <title>mod_proxy - Apache HTTP Server</title>
9 <link href="../style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" />
10 <link href="../style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" />
11 <link href="../style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" /><link rel="stylesheet" type="text/css" href="../style/css/prettify.css" />
12 <script src="../style/scripts/prettify.js" type="text/javascript">
15 <link href="../images/favicon.ico" rel="shortcut icon" /></head>
17 <div id="page-header">
18 <p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p>
19 <p class="apache">Apache HTTP Server Version 2.5</p>
20 <img alt="" src="../images/feather.gif" /></div>
21 <div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div>
23 <a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.5</a> > <a href="./">Modules</a></div>
24 <div id="page-content">
25 <div id="preamble"><h1>Apache Module mod_proxy</h1>
27 <p><span>Available Languages: </span><a href="../en/mod/mod_proxy.html" title="English"> en </a> |
28 <a href="../fr/mod/mod_proxy.html" hreflang="fr" rel="alternate" title="Français"> fr </a> |
29 <a href="../ja/mod/mod_proxy.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a></p>
31 <table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Multi-protocol proxy/gateway server</td></tr>
32 <tr><th><a href="module-dict.html#Status">Status:</a></th><td>Extension</td></tr>
33 <tr><th><a href="module-dict.html#ModuleIdentifier">Module Identifier:</a></th><td>proxy_module</td></tr>
34 <tr><th><a href="module-dict.html#SourceFile">Source File:</a></th><td>mod_proxy.c</td></tr></table>
37 <div class="warning"><h3>Warning</h3>
38 <p>Do not enable proxying with <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> until you have <a href="#access">secured your server</a>. Open proxy servers are dangerous both to your
39 network and to the Internet at large.</p>
42 <p><code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> and related modules implement a
43 proxy/gateway for Apache HTTP Server, supporting a number of popular
44 protocols as well as several different load balancing algorithms.
45 Third-party modules can add support for additional protocols and
46 load balancing algorithms.</p>
48 <p>A set of modules must be loaded into the server to provide the
49 necessary features. These modules can be included statically at
50 build time or dynamically via the
51 <code class="directive"><a href="../mod/mod_so.html#loadmodule">LoadModule</a></code> directive).
52 The set must include:</p>
55 <li><code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>, which provides basic proxy
58 <li><code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code> and one or more
59 balancer modules, if load balancing is required. (See
60 <code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code> for more information.)</li>
62 <li>one or more proxy scheme, or protocol, modules:
64 <table class="bordered">
65 <tr><th>Protocol</th><th>Module</th></tr>
66 <tr><td>AJP13 (Apache JServe Protocol version
67 1.3)</td><td><code class="module"><a href="../mod/mod_proxy_ajp.html">mod_proxy_ajp</a></code></td></tr>
69 SSL)</td><td><code class="module"><a href="../mod/mod_proxy_connect.html">mod_proxy_connect</a></code></td></tr>
70 <tr><td>FastCGI</td><td><code class="module"><a href="../mod/mod_proxy_fcgi.html">mod_proxy_fcgi</a></code></td></tr>
71 <tr><td>ftp</td><td><code class="module"><a href="../mod/mod_proxy_ftp.html">mod_proxy_ftp</a></code></td></tr>
72 <tr><td>HTTP/0.9, HTTP/1.0, and
73 HTTP/1.1</td><td><code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code></td></tr>
74 <tr><td>SCGI</td><td><code class="module"><a href="../mod/mod_proxy_scgi.html">mod_proxy_scgi</a></code></td></tr>
79 <p>In addition, extended features are provided by other modules.
80 Caching is provided by <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code> and related
81 modules. The ability to contact remote servers using the SSL/TLS
82 protocol is provided by the <code>SSLProxy*</code> directives of
83 <code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code>. These additional modules will need
84 to be loaded and configured to take advantage of these features.</p>
86 <div id="quickview"><h3 class="directives">Directives</h3>
88 <li><img alt="" src="../images/down.gif" /> <a href="#balancergrowth">BalancerGrowth</a></li>
89 <li><img alt="" src="../images/down.gif" /> <a href="#balancerinherit">BalancerInherit</a></li>
90 <li><img alt="" src="../images/down.gif" /> <a href="#balancermember">BalancerMember</a></li>
91 <li><img alt="" src="../images/down.gif" /> <a href="#balancerpersist">BalancerPersist</a></li>
92 <li><img alt="" src="../images/down.gif" /> <a href="#noproxy">NoProxy</a></li>
93 <li><img alt="" src="../images/down.gif" /> <a href="#proxy"><Proxy></a></li>
94 <li><img alt="" src="../images/down.gif" /> <a href="#proxyaddheaders">ProxyAddHeaders</a></li>
95 <li><img alt="" src="../images/down.gif" /> <a href="#proxybadheader">ProxyBadHeader</a></li>
96 <li><img alt="" src="../images/down.gif" /> <a href="#proxyblock">ProxyBlock</a></li>
97 <li><img alt="" src="../images/down.gif" /> <a href="#proxydomain">ProxyDomain</a></li>
98 <li><img alt="" src="../images/down.gif" /> <a href="#proxyerroroverride">ProxyErrorOverride</a></li>
99 <li><img alt="" src="../images/down.gif" /> <a href="#proxyiobuffersize">ProxyIOBufferSize</a></li>
100 <li><img alt="" src="../images/down.gif" /> <a href="#proxymatch"><ProxyMatch></a></li>
101 <li><img alt="" src="../images/down.gif" /> <a href="#proxymaxforwards">ProxyMaxForwards</a></li>
102 <li><img alt="" src="../images/down.gif" /> <a href="#proxypass">ProxyPass</a></li>
103 <li><img alt="" src="../images/down.gif" /> <a href="#proxypassinterpolateenv">ProxyPassInterpolateEnv</a></li>
104 <li><img alt="" src="../images/down.gif" /> <a href="#proxypassmatch">ProxyPassMatch</a></li>
105 <li><img alt="" src="../images/down.gif" /> <a href="#proxypassreverse">ProxyPassReverse</a></li>
106 <li><img alt="" src="../images/down.gif" /> <a href="#proxypassreversecookiedomain">ProxyPassReverseCookieDomain</a></li>
107 <li><img alt="" src="../images/down.gif" /> <a href="#proxypassreversecookiepath">ProxyPassReverseCookiePath</a></li>
108 <li><img alt="" src="../images/down.gif" /> <a href="#proxypreservehost">ProxyPreserveHost</a></li>
109 <li><img alt="" src="../images/down.gif" /> <a href="#proxyreceivebuffersize">ProxyReceiveBufferSize</a></li>
110 <li><img alt="" src="../images/down.gif" /> <a href="#proxyremote">ProxyRemote</a></li>
111 <li><img alt="" src="../images/down.gif" /> <a href="#proxyremotematch">ProxyRemoteMatch</a></li>
112 <li><img alt="" src="../images/down.gif" /> <a href="#proxyrequests">ProxyRequests</a></li>
113 <li><img alt="" src="../images/down.gif" /> <a href="#proxyset">ProxySet</a></li>
114 <li><img alt="" src="../images/down.gif" /> <a href="#proxysourceaddress">ProxySourceAddress</a></li>
115 <li><img alt="" src="../images/down.gif" /> <a href="#proxystatus">ProxyStatus</a></li>
116 <li><img alt="" src="../images/down.gif" /> <a href="#proxytimeout">ProxyTimeout</a></li>
117 <li><img alt="" src="../images/down.gif" /> <a href="#proxyvia">ProxyVia</a></li>
121 <li><img alt="" src="../images/down.gif" /> <a href="#forwardreverse">Forward Proxies and Reverse
122 Proxies/Gateways</a></li>
123 <li><img alt="" src="../images/down.gif" /> <a href="#examples">Basic Examples</a></li>
124 <li><img alt="" src="../images/down.gif" /> <a href="#workers">Workers</a></li>
125 <li><img alt="" src="../images/down.gif" /> <a href="#access">Controlling access to your proxy</a></li>
126 <li><img alt="" src="../images/down.gif" /> <a href="#startup">Slow Startup</a></li>
127 <li><img alt="" src="../images/down.gif" /> <a href="#intranet">Intranet Proxy</a></li>
128 <li><img alt="" src="../images/down.gif" /> <a href="#envsettings">Protocol Adjustments</a></li>
129 <li><img alt="" src="../images/down.gif" /> <a href="#request-bodies">Request Bodies</a></li>
130 <li><img alt="" src="../images/down.gif" /> <a href="#x-headers">Reverse Proxy Request Headers</a></li>
131 </ul><h3>See also</h3>
133 <li><code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code></li>
134 <li><code class="module"><a href="../mod/mod_proxy_ajp.html">mod_proxy_ajp</a></code></li>
135 <li><code class="module"><a href="../mod/mod_proxy_connect.html">mod_proxy_connect</a></code></li>
136 <li><code class="module"><a href="../mod/mod_proxy_fcgi.html">mod_proxy_fcgi</a></code></li>
137 <li><code class="module"><a href="../mod/mod_proxy_ftp.html">mod_proxy_ftp</a></code></li>
138 <li><code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code></li>
139 <li><code class="module"><a href="../mod/mod_proxy_scgi.html">mod_proxy_scgi</a></code></li>
140 <li><code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code></li>
141 <li><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></li>
142 </ul><ul class="seealso"><li><a href="#comments_section">Comments</a></li></ul></div>
143 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
144 <div class="section">
145 <h2><a name="forwardreverse" id="forwardreverse">Forward Proxies and Reverse
146 Proxies/Gateways</a></h2>
147 <p>Apache HTTP Server can be configured in both a <dfn>forward</dfn> and
148 <dfn>reverse</dfn> proxy (also known as <dfn>gateway</dfn>) mode.</p>
150 <p>An ordinary <dfn>forward proxy</dfn> is an intermediate
151 server that sits between the client and the <em>origin
152 server</em>. In order to get content from the origin server,
153 the client sends a request to the proxy naming the origin server
154 as the target and the proxy then requests the content from the
155 origin server and returns it to the client. The client must be
156 specially configured to use the forward proxy to access other
159 <p>A typical usage of a forward proxy is to provide Internet
160 access to internal clients that are otherwise restricted by a
161 firewall. The forward proxy can also use caching (as provided
162 by <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code>) to reduce network usage.</p>
164 <p>The forward proxy is activated using the <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> directive. Because
165 forward proxies allow clients to access arbitrary sites through
166 your server and to hide their true origin, it is essential that
167 you <a href="#access">secure your server</a> so that only
168 authorized clients can access the proxy before activating a
171 <p>A <dfn>reverse proxy</dfn> (or <dfn>gateway</dfn>), by
172 contrast, appears to the client just like an ordinary web
173 server. No special configuration on the client is necessary.
174 The client makes ordinary requests for content in the name-space
175 of the reverse proxy. The reverse proxy then decides where to
176 send those requests, and returns the content as if it was itself
179 <p>A typical usage of a reverse proxy is to provide Internet
180 users access to a server that is behind a firewall. Reverse
181 proxies can also be used to balance load among several back-end
182 servers, or to provide caching for a slower back-end server.
183 In addition, reverse proxies can be used simply to bring
184 several servers into the same URL space.</p>
186 <p>A reverse proxy is activated using the <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive or the
187 <code>[P]</code> flag to the <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> directive. It is
188 <strong>not</strong> necessary to turn <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> on in order to
189 configure a reverse proxy.</p>
190 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
191 <div class="section">
192 <h2><a name="examples" id="examples">Basic Examples</a></h2>
194 <p>The examples below are only a very basic idea to help you
195 get started. Please read the documentation on the individual
198 <p>In addition, if you wish to have caching enabled, consult
199 the documentation from <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code>.</p>
201 <div class="example"><h3>Reverse Proxy</h3><pre class="prettyprint lang-config">
202 ProxyPass /foo http://foo.example.com/bar
203 ProxyPassReverse /foo http://foo.example.com/bar
207 <div class="example"><h3>Forward Proxy</h3><pre class="prettyprint lang-config">
212 Require host internal.example.com
216 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
217 <div class="section">
218 <h2><a name="workers" id="workers">Workers</a></h2>
219 <p>The proxy manages the configuration of origin servers and their
220 communication parameters in objects called <dfn>workers</dfn>.
221 There are two built-in workers, the default forward proxy worker and the
222 default reverse proxy worker. Additional workers can be configured
225 <p>The two default workers have a fixed configuration
226 and will be used if no other worker matches the request.
227 They do not use HTTP Keep-Alive or connection pooling.
228 The TCP connections to the origin server will instead be
229 opened and closed for each request.</p>
231 <p>Explicitly configured workers are identified by their URL.
232 They are usually created and configured using
233 <code class="directive"><a href="#proxypass">ProxyPass</a></code> or
234 <code class="directive"><a href="#proxypassmatch">ProxyPassMatch</a></code> when used
235 for a reverse proxy:</p>
237 <pre class="prettyprint lang-config">
238 ProxyPass /example http://backend.example.com connectiontimeout=5 timeout=30
242 <p>This will create a worker associated with the origin server URL
243 <code>http://backend.example.com</code> and using the given timeout
244 values. When used in a forward proxy, workers are usually defined
245 via the <code class="directive"><a href="#proxyset">ProxySet</a></code> directive:</p>
247 <pre class="prettyprint lang-config">
248 ProxySet http://backend.example.com connectiontimeout=5 timeout=30
252 <p>or alternatively using <code class="directive"><a href="#proxy">Proxy</a></code>
253 and <code class="directive"><a href="#proxyset">ProxySet</a></code>:</p>
255 <pre class="prettyprint lang-config">
256 <Proxy http://backend.example.com>
257 ProxySet connectiontimeout=5 timeout=30
262 <p>Using explicitly configured workers in the forward mode is
263 not very common, because forward proxies usually communicate with many
264 different origin servers. Creating explicit workers for some of the
265 origin servers can still be useful, if they are used very often.
266 Explicitly configured workers have no concept of forward or reverse
267 proxying by themselves. They encapsulate a common concept of
268 communication with origin servers. A worker created by
269 <code class="directive"><a href="#proxypass">ProxyPass</a></code> for use in a
270 reverse proxy will be also used for forward proxy requests whenever
271 the URL to the origin server matches the worker URL and vice versa.</p>
273 <p>The URL identifying a direct worker is the URL of its
274 origin server including any path components given:</p>
276 <pre class="prettyprint lang-config">
277 ProxyPass /examples http://backend.example.com/examples
278 ProxyPass /docs http://backend.example.com/docs
282 <p>This example defines two different workers, each using a separate
283 connection pool and configuration.</p>
285 <div class="warning"><h3>Worker Sharing</h3>
286 <p>Worker sharing happens if the worker URLs overlap, which occurs when
287 the URL of some worker is a leading substring of the URL of another
288 worker defined later in the configuration file. In the following example</p>
290 <pre class="prettyprint lang-config">
291 ProxyPass /apps http://backend.example.com/ timeout=60
292 ProxyPass /examples http://backend.example.com/examples timeout=10
296 <p>the second worker isn't actually created. Instead the first
297 worker is used. The benefit is, that there is only one connection pool,
298 so connections are more often reused. Note that all configuration attributes
299 given explicitly for the later worker will be ignored. This will be logged
300 as a warning. In the above example the resulting timeout value
301 for the URL <code>/examples</code> will be <code>60</code> instead
302 of <code>10</code>!</p>
304 <p>If you want to avoid worker sharing, sort your worker definitions
305 by URL length, starting with the longest worker URLs. If you want to maximize
306 worker sharing use the reverse sort order. See also the related warning about
307 ordering <code class="directive"><a href="#proxypass">ProxyPass</a></code> directives.</p>
311 <p>Explicitly configured workers come in two flavors:
312 <dfn>direct workers</dfn> and <dfn>(load) balancer workers</dfn>.
313 They support many important configuration attributes which are
314 described below in the <code class="directive"><a href="#proxypass">ProxyPass</a></code>
315 directive. The same attributes can also be set using
316 <code class="directive"><a href="#proxyset">ProxySet</a></code>.</p>
318 <p>The set of options available for a direct worker
319 depends on the protocol, which is specified in the origin server URL.
320 Available protocols include <code>ajp</code>, <code>fcgi</code>,
321 <code>ftp</code>, <code>http</code> and <code>scgi</code>.</p>
323 <p>Balancer workers are virtual workers that use direct workers known
324 as their members to actually handle the requests. Each balancer can
325 have multiple members. When it handles a request, it chooses a member
326 based on the configured load balancing algorithm.</p>
328 <p>A balancer worker is created if its worker URL uses
329 <code>balancer</code> as the protocol scheme.
330 The balancer URL uniquely identifies the balancer worker.
331 Members are added to a balancer using
332 <code class="directive"><a href="#balancermember">BalancerMember</a></code>.</p>
334 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
335 <div class="section">
336 <h2><a name="access" id="access">Controlling access to your proxy</a></h2>
337 <p>You can control who can access your proxy via the <code class="directive"><a href="#proxy"><Proxy></a></code> control block as in
338 the following example:</p>
340 <pre class="prettyprint lang-config">
347 <p>For more information on access control directives, see
348 <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code>.</p>
350 <p>Strictly limiting access is essential if you are using a
351 forward proxy (using the <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> directive).
352 Otherwise, your server can be used by any client to access
353 arbitrary hosts while hiding his or her true identity. This is
354 dangerous both for your network and for the Internet at large.
355 When using a reverse proxy (using the <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive with
356 <code>ProxyRequests Off</code>), access control is less
357 critical because clients can only contact the hosts that you
358 have specifically configured.</p>
360 <p><strong>See Also</strong> the <a href="mod_proxy_http.html#env">Proxy-Chain-Auth</a> environment variable.</p>
362 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
363 <div class="section">
364 <h2><a name="startup" id="startup">Slow Startup</a></h2>
365 <p>If you're using the <code class="directive"><a href="#proxyblock">ProxyBlock</a></code> directive, hostnames' IP addresses are looked up
366 and cached during startup for later match test. This may take a few
367 seconds (or more) depending on the speed with which the hostname lookups
369 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
370 <div class="section">
371 <h2><a name="intranet" id="intranet">Intranet Proxy</a></h2>
372 <p>An Apache httpd proxy server situated in an intranet needs to forward
373 external requests through the company's firewall (for this, configure
374 the <code class="directive"><a href="#proxyremote">ProxyRemote</a></code> directive
375 to forward the respective <var>scheme</var> to the firewall proxy).
376 However, when it has to
377 access resources within the intranet, it can bypass the firewall when
378 accessing hosts. The <code class="directive"><a href="#noproxy">NoProxy</a></code>
379 directive is useful for specifying which hosts belong to the intranet and
380 should be accessed directly.</p>
382 <p>Users within an intranet tend to omit the local domain name from their
383 WWW requests, thus requesting "http://somehost/" instead of
384 <code>http://somehost.example.com/</code>. Some commercial proxy servers
385 let them get away with this and simply serve the request, implying a
386 configured local domain. When the <code class="directive"><a href="#proxydomain">ProxyDomain</a></code> directive is used and the server is <a href="#proxyrequests">configured for proxy service</a>, Apache httpd can return
387 a redirect response and send the client to the correct, fully qualified,
388 server address. This is the preferred method since the user's bookmark
389 files will then contain fully qualified hosts.</p>
390 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
391 <div class="section">
392 <h2><a name="envsettings" id="envsettings">Protocol Adjustments</a></h2>
393 <p>For circumstances where <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> is sending
394 requests to an origin server that doesn't properly implement
395 keepalives or HTTP/1.1, there are two <a href="../env.html">environment variables</a> that can force the
396 request to use HTTP/1.0 with no keepalive. These are set via the
397 <code class="directive"><a href="../mod/mod_env.html#setenv">SetEnv</a></code> directive.</p>
399 <p>These are the <code>force-proxy-request-1.0</code> and
400 <code>proxy-nokeepalive</code> notes.</p>
402 <pre class="prettyprint lang-config">
403 <Location /buggyappserver/>
404 ProxyPass http://buggyappserver:7001/foo/
405 SetEnv force-proxy-request-1.0 1
406 SetEnv proxy-nokeepalive 1
411 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
412 <div class="section">
413 <h2><a name="request-bodies" id="request-bodies">Request Bodies</a></h2>
415 <p>Some request methods such as POST include a request body.
416 The HTTP protocol requires that requests which include a body
417 either use chunked transfer encoding or send a
418 <code>Content-Length</code> request header. When passing these
419 requests on to the origin server, <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code>
420 will always attempt to send the <code>Content-Length</code>. But
421 if the body is large and the original request used chunked
422 encoding, then chunked encoding may also be used in the upstream
423 request. You can control this selection using <a href="../env.html">environment variables</a>. Setting
424 <code>proxy-sendcl</code> ensures maximum compatibility with
425 upstream servers by always sending the
426 <code>Content-Length</code>, while setting
427 <code>proxy-sendchunked</code> minimizes resource usage by using
428 chunked encoding.</p>
430 <p>Under some circumstances, the server must spool request bodies
431 to disk to satisfy the requested handling of request bodies. For
432 example, this spooling will occur if the original body was sent with
433 chunked encoding (and is large), but the administrator has
434 asked for backend requests to be sent with Content-Length or as HTTP/1.0.
435 This spooling can also occur if the request body already has a
436 Content-Length header, but the server is configured to filter incoming
439 <p><code class="directive"><a href="../mod/core.html#limitrequestbody">LimitRequestBody</a></code> only applies to
440 request bodies that the server will spool to disk</p>
442 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
443 <div class="section">
444 <h2><a name="x-headers" id="x-headers">Reverse Proxy Request Headers</a></h2>
446 <p>When acting in a reverse-proxy mode (using the <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive, for example),
447 <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code> adds several request headers in
448 order to pass information to the origin server. These headers
452 <dt><code>X-Forwarded-For</code></dt>
453 <dd>The IP address of the client.</dd>
454 <dt><code>X-Forwarded-Host</code></dt>
455 <dd>The original host requested by the client in the <code>Host</code>
456 HTTP request header.</dd>
457 <dt><code>X-Forwarded-Server</code></dt>
458 <dd>The hostname of the proxy server.</dd>
461 <p>Be careful when using these headers on the origin server, since
462 they will contain more than one (comma-separated) value if the
463 original request already contained one of these headers. For
464 example, you can use <code>%{X-Forwarded-For}i</code> in the log
465 format string of the origin server to log the original clients IP
466 address, but you may get more than one address if the request
467 passes through several proxies.</p>
469 <p>See also the <code class="directive"><a href="#proxypreservehost">ProxyPreserveHost</a></code> and <code class="directive"><a href="#proxyvia">ProxyVia</a></code> directives, which control
470 other request headers.</p>
473 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
474 <div class="directive-section"><h2><a name="BalancerGrowth" id="BalancerGrowth">BalancerGrowth</a> <a name="balancergrowth" id="balancergrowth">Directive</a></h2>
475 <table class="directive">
476 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of additional Balancers that can be added Post-configuration</td></tr>
477 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>BalancerGrowth <var>#</var></code></td></tr>
478 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>BalancerGrowth 5</code></td></tr>
479 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
480 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
481 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
482 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>BalancerGrowth is only available in Apache HTTP Server 2.3.13
485 <p>This directive allows for growth potential in the number of
486 Balancers available for a virtualhost in addition to the
487 number pre-configured. It only takes effect if there is at
488 least 1 pre-configured Balancer.</p>
491 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
492 <div class="directive-section"><h2><a name="BalancerInherit" id="BalancerInherit">BalancerInherit</a> <a name="balancerinherit" id="balancerinherit">Directive</a></h2>
493 <table class="directive">
494 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Inherit ProxyPassed Balancers/Workers from the main server</td></tr>
495 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassInherit On|Off</code></td></tr>
496 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyPassInherit On</code></td></tr>
497 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
498 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
499 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
500 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>ProxyPassInherit is only available in Apache HTTP Server 2.5.0
503 <p>This directive will cause the current server/vhost to "inherit" ProxyPass
504 Balancers and Workers defined in the main server. This can cause issues and
505 inconsistent behavior if using the Balancer Manager and so should be disabled
506 if using that feature.</p>
507 <p>The setting in the global server defines the default for all vhosts.</p>
510 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
511 <div class="directive-section"><h2><a name="BalancerMember" id="BalancerMember">BalancerMember</a> <a name="balancermember" id="balancermember">Directive</a></h2>
512 <table class="directive">
513 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Add a member to a load balancing group</td></tr>
514 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>BalancerMember [<var>balancerurl</var>] <var>url</var> [<var>key=value [key=value ...]]</var></code></td></tr>
515 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
516 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
517 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
519 <p>This directive adds a member to a load balancing group. It could be used
520 within a <code><Proxy <var>balancer://</var>...></code> container
521 directive, and can take any of the key value pair parameters available to
522 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directives.</p>
523 <p>One additional parameter is available only to <code class="directive"><a href="#balancermember">BalancerMember</a></code> directives:
524 <var>loadfactor</var>. This is the member load factor - a number between 1
525 (default) and 100, which defines the weighted load to be applied to the
526 member in question.</p>
527 <p>The balancerurl is only needed when not in <code><Proxy <var>balancer://</var>...></code>
528 container directive. It corresponds to the url of a balancer defined in
529 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.</p>
530 <p>The path component of the balancer URL in any
531 <code><Proxy <var>balancer://</var>...></code> container directive
533 <p>Trailing slashes should typically be removed from the URL of a
534 <code>BalancerMember</code>.</p>
537 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
538 <div class="directive-section"><h2><a name="BalancerPersist" id="BalancerPersist">BalancerPersist</a> <a name="balancerpersist" id="balancerpersist">Directive</a></h2>
539 <table class="directive">
540 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Attempt to persist changes made by the Balancer Manager across restarts.</td></tr>
541 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>BalancerPersist On|Off</code></td></tr>
542 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>BalancerPersist Off</code></td></tr>
543 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
544 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
545 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
546 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>BalancerPersist is only available in Apache HTTP Server 2.5.0
549 <p>This directive will cause the shared memory storage associated
550 with the balancers and balancer members to be persisted across
551 restarts. This allows these local changes to not be lost during the
552 normal restart/graceful state transitions.</p>
555 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
556 <div class="directive-section"><h2><a name="NoProxy" id="NoProxy">NoProxy</a> <a name="noproxy" id="noproxy">Directive</a></h2>
557 <table class="directive">
558 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Hosts, domains, or networks that will be connected to
560 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>NoProxy <var>host</var> [<var>host</var>] ...</code></td></tr>
561 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
562 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
563 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
565 <p>This directive is only useful for Apache httpd proxy servers within
566 intranets. The <code class="directive">NoProxy</code> directive specifies a
567 list of subnets, IP addresses, hosts and/or domains, separated by
568 spaces. A request to a host which matches one or more of these is
569 always served directly, without forwarding to the configured
570 <code class="directive"><a href="#proxyremote">ProxyRemote</a></code> proxy server(s).</p>
572 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">
573 ProxyRemote * http://firewall.example.com:81
574 NoProxy .example.com 192.168.112.0/21
578 <p>The <var>host</var> arguments to the <code class="directive">NoProxy</code>
579 directive are one of the following type list:</p>
583 <dt><var><a name="domain" id="domain">Domain</a></var></dt>
585 <p>A <dfn>Domain</dfn> is a partially qualified DNS domain name, preceded
586 by a period. It represents a list of hosts which logically belong to the
587 same DNS domain or zone (<em>i.e.</em>, the suffixes of the hostnames are
588 all ending in <var>Domain</var>).</p>
590 <div class="example"><h3>Examples</h3><p><code>
594 <p>To distinguish <var>Domain</var>s from <var><a href="#hostname">Hostname</a></var>s (both syntactically and semantically; a DNS domain can
595 have a DNS A record, too!), <var>Domain</var>s are always written with a
598 <div class="note"><h3>Note</h3>
599 <p>Domain name comparisons are done without regard to the case, and
600 <var>Domain</var>s are always assumed to be anchored in the root of the
601 DNS tree, therefore two domains <code>.ExAmple.com</code> and
602 <code>.example.com.</code> (note the trailing period) are considered
603 equal. Since a domain comparison does not involve a DNS lookup, it is much
604 more efficient than subnet comparison.</p>
608 <dt><var><a name="subnet" id="subnet">SubNet</a></var></dt>
610 <p>A <dfn>SubNet</dfn> is a partially qualified internet address in
611 numeric (dotted quad) form, optionally followed by a slash and the netmask,
612 specified as the number of significant bits in the <var>SubNet</var>. It is
613 used to represent a subnet of hosts which can be reached over a common
614 network interface. In the absence of the explicit net mask it is assumed
615 that omitted (or zero valued) trailing digits specify the mask. (In this
616 case, the netmask can only be multiples of 8 bits wide.) Examples:</p>
619 <dt><code>192.168</code> or <code>192.168.0.0</code></dt>
620 <dd>the subnet 192.168.0.0 with an implied netmask of 16 valid bits
621 (sometimes used in the netmask form <code>255.255.0.0</code>)</dd>
622 <dt><code>192.168.112.0/21</code></dt>
623 <dd>the subnet <code>192.168.112.0/21</code> with a netmask of 21
624 valid bits (also used in the form <code>255.255.248.0</code>)</dd>
627 <p>As a degenerate case, a <em>SubNet</em> with 32 valid bits is the
628 equivalent to an <var><a href="#ipaddr">IPAddr</a></var>, while a <var>SubNet</var> with zero
629 valid bits (<em>e.g.</em>, 0.0.0.0/0) is the same as the constant
630 <var>_Default_</var>, matching any IP address.</p></dd>
633 <dt><var><a name="ipaddr" id="ipaddr">IPAddr</a></var></dt>
635 <p>A <dfn>IPAddr</dfn> represents a fully qualified internet address in
636 numeric (dotted quad) form. Usually, this address represents a host, but
637 there need not necessarily be a DNS domain name connected with the
639 <div class="example"><h3>Example</h3><p><code>
643 <div class="note"><h3>Note</h3>
644 <p>An <var>IPAddr</var> does not need to be resolved by the DNS system, so
645 it can result in more effective apache performance.</p>
649 <dt><var><a name="hostname" id="hostname">Hostname</a></var></dt>
651 <p>A <dfn>Hostname</dfn> is a fully qualified DNS domain name which can
652 be resolved to one or more <var><a href="#ipaddr">IPAddrs</a></var> via the
653 DNS domain name service. It represents a logical host (in contrast to
654 <var><a href="#domain">Domain</a></var>s, see above) and must be resolvable
655 to at least one <var><a href="#ipaddr">IPAddr</a></var> (or often to a list
656 of hosts with different <var><a href="#ipaddr">IPAddr</a></var>s).</p>
658 <div class="example"><h3>Examples</h3><p><code>
659 prep.ai.example.edu<br />
663 <div class="note"><h3>Note</h3>
664 <p>In many situations, it is more effective to specify an <var><a href="#ipaddr">IPAddr</a></var> in place of a <var>Hostname</var> since a
665 DNS lookup can be avoided. Name resolution in Apache httpd can take a remarkable
666 deal of time when the connection to the name server uses a slow PPP
668 <p><var>Hostname</var> comparisons are done without regard to the case,
669 and <var>Hostname</var>s are always assumed to be anchored in the root
670 of the DNS tree, therefore two hosts <code>WWW.ExAmple.com</code>
671 and <code>www.example.com.</code> (note the trailing period) are
672 considered equal.</p>
678 <li><a href="../dns-caveats.html">DNS Issues</a></li>
681 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
682 <div class="directive-section"><h2><a name="Proxy" id="Proxy"><Proxy></a> <a name="proxy" id="proxy">Directive</a></h2>
683 <table class="directive">
684 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Container for directives applied to proxied resources</td></tr>
685 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Proxy <var>wildcard-url</var>> ...</Proxy></code></td></tr>
686 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
687 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
688 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
690 <p>Directives placed in <code class="directive"><Proxy></code>
691 sections apply only to matching proxied content. Shell-style wildcards are
694 <p>For example, the following will allow only hosts in
695 <code>yournetwork.example.com</code> to access content via your proxy
698 <pre class="prettyprint lang-config">
700 Require host yournetwork.example.com
705 <p>The following example will process all files in the <code>foo</code>
706 directory of <code>example.com</code> through the <code>INCLUDES</code>
707 filter when they are sent through the proxy server:</p>
709 <pre class="prettyprint lang-config">
710 <Proxy http://example.com/foo/*>
711 SetOutputFilter INCLUDES
719 <li><code class="directive"><a href="#proxymatch"><ProxyMatch></a></code></li>
722 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
723 <div class="directive-section"><h2><a name="ProxyAddHeaders" id="ProxyAddHeaders">ProxyAddHeaders</a> <a name="proxyaddheaders" id="proxyaddheaders">Directive</a></h2>
724 <table class="directive">
725 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Add proxy information in X-Forwarded-* headers</td></tr>
726 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyAddHeaders Off|On</code></td></tr>
727 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyAddHeaders On</code></td></tr>
728 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
729 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
730 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
731 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in version 2.3.10 and later</td></tr>
733 <p>This directive determines whether or not proxy related information should be passed to the
734 backend server through X-Forwarded-For, X-Forwarded-Host and X-Forwarded-Server HTTP headers.</p>
735 <div class="note"><h3>Effectiveness</h3>
736 <p>This option is of use only for HTTP proxying, as handled by <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code>.</p>
740 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
741 <div class="directive-section"><h2><a name="ProxyBadHeader" id="ProxyBadHeader">ProxyBadHeader</a> <a name="proxybadheader" id="proxybadheader">Directive</a></h2>
742 <table class="directive">
743 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines how to handle bad header lines in a
745 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyBadHeader IsError|Ignore|StartBody</code></td></tr>
746 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyBadHeader IsError</code></td></tr>
747 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
748 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
749 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
751 <p>The <code class="directive">ProxyBadHeader</code> directive determines the
752 behaviour of <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> if it receives syntactically invalid
753 response header lines (<em>i.e.</em> containing no colon) from the origin
754 server. The following arguments are possible:</p>
757 <dt><code>IsError</code></dt>
758 <dd>Abort the request and end up with a 502 (Bad Gateway) response. This is
759 the default behaviour.</dd>
761 <dt><code>Ignore</code></dt>
762 <dd>Treat bad header lines as if they weren't sent.</dd>
764 <dt><code>StartBody</code></dt>
765 <dd>When receiving the first bad header line, finish reading the headers and
766 treat the remainder as body. This helps to work around buggy backend servers
767 which forget to insert an empty line between the headers and the body.</dd>
771 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
772 <div class="directive-section"><h2><a name="ProxyBlock" id="ProxyBlock">ProxyBlock</a> <a name="proxyblock" id="proxyblock">Directive</a></h2>
773 <table class="directive">
774 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Disallow proxy requests to certain hosts</td></tr>
775 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyBlock *|<var>hostname</var>|<var>partial-hostname</var> [<var>hostname</var>|<var>partial-hostname</var>]...</code></td></tr>
776 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
777 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
778 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
780 <p>The <code class="directive">ProxyBlock</code> directive can be used to
781 block FTP or HTTP access to certain hosts via the proxy, based on
782 a full or partial hostname match, or, if applicable, an IP address
785 <p>Each of the arguments to the <code class="directive">ProxyBlock</code>
786 directive can be either <code>*</code> or a alphanumeric string.
787 At startup, the module will attempt to resolve every alphanumeric
788 string from a DNS name to a set of IP addresses, but any DNS errors
791 <p>If an asterisk "<code>*</code>" argument is specified,
792 <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> will deny access to all FTP or HTTP
795 <p>Otherwise, for any request for an HTTP or FTP resource via the
796 proxy, <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> will check the hostname of the
797 request URI against each specified string. If a partial string
798 match is found, access is denied. If no matches against hostnames
799 are found, and a remote (forward) proxy is configured using
800 <code class="directive">ProxyRemote</code> or
801 <code class="directive">ProxyRemoteMatch</code>, access is allowed. If no
802 remote (forward) proxy is configured, the IP address of the
803 hostname from the URI is compared against all resolved IP
804 addresses determined at startup. Access is denied if any match is
807 <p>Note that the DNS lookups may slow down the startup time of the
810 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">
811 ProxyBlock news.example.com auctions.example.com friends.example.com
815 <p>Note that <code>example</code> would also be sufficient to match any
818 <p>Hosts would also be matched if referenced by IP address.</p>
820 <p>Note also that</p>
822 <pre class="prettyprint lang-config">
827 <p>blocks connections to all sites.</p>
830 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
831 <div class="directive-section"><h2><a name="ProxyDomain" id="ProxyDomain">ProxyDomain</a> <a name="proxydomain" id="proxydomain">Directive</a></h2>
832 <table class="directive">
833 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Default domain name for proxied requests</td></tr>
834 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyDomain <var>Domain</var></code></td></tr>
835 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
836 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
837 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
839 <p>This directive is only useful for Apache httpd proxy servers within
840 intranets. The <code class="directive">ProxyDomain</code> directive specifies
841 the default domain which the apache proxy server will belong to. If a
842 request to a host without a domain name is encountered, a redirection
843 response to the same host with the configured <var>Domain</var> appended
844 will be generated.</p>
846 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">
847 ProxyRemote * http://firewall.example.com:81<br />
848 NoProxy .example.com 192.168.112.0/21<br />
849 ProxyDomain .example.com
854 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
855 <div class="directive-section"><h2><a name="ProxyErrorOverride" id="ProxyErrorOverride">ProxyErrorOverride</a> <a name="proxyerroroverride" id="proxyerroroverride">Directive</a></h2>
856 <table class="directive">
857 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Override error pages for proxied content</td></tr>
858 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyErrorOverride On|Off</code></td></tr>
859 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyErrorOverride Off</code></td></tr>
860 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
861 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
862 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
864 <p>This directive is useful for reverse-proxy setups, where you want to
865 have a common look and feel on the error pages seen by the end user.
866 This also allows for included files (via
867 <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>'s SSI) to get
868 the error code and act accordingly (default behavior would display
869 the error page of the proxied server, turning this on shows the SSI
872 <p>This directive does not affect the processing of informational (1xx),
873 normal success (2xx), or redirect (3xx) responses.</p>
876 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
877 <div class="directive-section"><h2><a name="ProxyIOBufferSize" id="ProxyIOBufferSize">ProxyIOBufferSize</a> <a name="proxyiobuffersize" id="proxyiobuffersize">Directive</a></h2>
878 <table class="directive">
879 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine size of internal data throughput buffer</td></tr>
880 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyIOBufferSize <var>bytes</var></code></td></tr>
881 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyIOBufferSize 8192</code></td></tr>
882 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
883 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
884 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
886 <p>The <code class="directive">ProxyIOBufferSize</code> directive adjusts the size
887 of the internal buffer, which is used as a scratchpad for the data between
888 input and output. The size must be at least <code>512</code>.</p>
890 <p>In almost every case there's no reason to change that value.</p>
891 <p>If used with AJP this directive sets the maximum AJP packet size in
892 bytes. If you change it from the default, you must also change the
893 <code>packetSize</code> attribute of your AJP connector on the
894 Tomcat side! The attribute <code>packetSize</code> is only available
895 in Tomcat <code>5.5.20+</code> and <code>6.0.2+</code></p>
896 <p>Normally it is not necessary to change the maximum packet size.
897 Problems with the default value have been reported when sending
898 certificates or certificate chains.</p>
902 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
903 <div class="directive-section"><h2><a name="ProxyMatch" id="ProxyMatch"><ProxyMatch></a> <a name="proxymatch" id="proxymatch">Directive</a></h2>
904 <table class="directive">
905 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Container for directives applied to regular-expression-matched
906 proxied resources</td></tr>
907 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><ProxyMatch <var>regex</var>> ...</ProxyMatch></code></td></tr>
908 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
909 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
910 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
912 <p>The <code class="directive"><ProxyMatch></code> directive is
913 identical to the <code class="directive"><a href="#proxy"><Proxy></a></code> directive, except it matches URLs
914 using <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expressions</a>.</p>
918 <li><code class="directive"><a href="#proxy"><Proxy></a></code></li>
921 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
922 <div class="directive-section"><h2><a name="ProxyMaxForwards" id="ProxyMaxForwards">ProxyMaxForwards</a> <a name="proxymaxforwards" id="proxymaxforwards">Directive</a></h2>
923 <table class="directive">
924 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximium number of proxies that a request can be forwarded
926 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyMaxForwards <var>number</var></code></td></tr>
927 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyMaxForwards -1</code></td></tr>
928 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
929 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
930 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
932 <p>The <code class="directive">ProxyMaxForwards</code> directive specifies the
933 maximum number of proxies through which a request may pass, if there's no
934 <code>Max-Forwards</code> header supplied with the request. This may
935 be set to prevent infinite proxy loops, or a DoS attack.</p>
937 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">
942 <p>Note that setting <code class="directive">ProxyMaxForwards</code> is a
943 violation of the HTTP/1.1 protocol (RFC2616), which forbids a Proxy
944 setting <code>Max-Forwards</code> if the Client didn't set it.
945 Earlier Apache httpd versions would always set it. A negative
946 <code class="directive">ProxyMaxForwards</code> value, including the
947 default -1, gives you protocol-compliant behaviour, but may
948 leave you open to loops.</p>
951 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
952 <div class="directive-section"><h2><a name="ProxyPass" id="ProxyPass">ProxyPass</a> <a name="proxypass" id="proxypass">Directive</a></h2>
953 <table class="directive">
954 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maps remote servers into the local server URL-space</td></tr>
955 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPass [<var>path</var>] !|<var>url</var> [<var>key=value</var>
956 <var>[key=value</var> ...]] [nocanon] [interpolate] [noquery]</code></td></tr>
957 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
958 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
959 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
961 <p>This directive allows remote servers to be mapped into the
962 space of the local server; the local server does not act as a
963 proxy in the conventional sense, but appears to be a mirror of the
964 remote server. The local server is often called a <dfn>reverse
965 proxy</dfn> or <dfn>gateway</dfn>. The <var>path</var> is the name of
966 a local virtual path; <var>url</var> is a partial URL for the
967 remote server and cannot include a query string.</p>
969 <div class="warning">The <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> directive should
970 usually be set <strong>off</strong> when using
971 <code class="directive">ProxyPass</code>.</div>
973 <p>Suppose the local server has address <code>http://example.com/</code>;
976 <pre class="prettyprint lang-config">
977 <Location /mirror/foo/>
978 ProxyPass http://backend.example.com/
983 <p>will cause a local request for
984 <code>http://example.com/mirror/foo/bar</code> to be internally converted
985 into a proxy request to <code>http://backend.example.com/bar</code>.</p>
987 <p>The following alternative syntax is possible, however it can carry a
988 performance penalty when present in very large numbers. The advantage of
989 the below syntax is that it allows for dynamic control via the
990 <a href="mod_proxy_balancer.html#balancer_manager">Balancer Manager</a> interface:</p>
992 <pre class="prettyprint lang-config">
993 ProxyPass /mirror/foo/ http://backend.example.com/
997 <div class="warning">
998 <p>If the first argument ends with a trailing <strong>/</strong>, the second
999 argument should also end with a trailing <strong>/</strong> and vice
1000 versa. Otherwise the resulting requests to the backend may miss some
1001 needed slashes and do not deliver the expected results.
1005 <p>The <code>!</code> directive is useful in situations where you don't want
1006 to reverse-proxy a subdirectory, <em>e.g.</em></p>
1008 <pre class="prettyprint lang-config">
1009 <Location /mirror/foo/>
1010 ProxyPass http://backend.example.com/
1012 <Location /mirror/foo/i>
1018 <pre class="prettyprint lang-config">
1019 ProxyPass /mirror/foo/i !
1020 ProxyPass /mirror/foo http://backend.example.com
1024 <p>will proxy all requests to <code>/mirror/foo</code> to
1025 <code>backend.example.com</code> <em>except</em> requests made to
1026 <code>/mirror/foo/i</code>.</p>
1028 <div class="warning"><h3>Ordering ProxyPass Directives</h3>
1029 <p>The configured <code class="directive"><a href="#proxypass">ProxyPass</a></code>
1030 and <code class="directive"><a href="#proxypassmatch">ProxyPassMatch</a></code>
1031 rules are checked in the order of configuration. The first rule that
1032 matches wins. So usually you should sort conflicting
1033 <code class="directive"><a href="#proxypass">ProxyPass</a></code> rules starting with the
1034 longest URLs first. Otherwise later rules for longer URLS will be hidden
1035 by any earlier rule which uses a leading substring of the URL. Note that
1036 there is some relation with worker sharing. In contrast, only one
1037 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive can be placed
1038 in a <code class="directive"><a href="../mod/core.html#location">Location</a></code> block, and the most
1039 specific location will take precedence.</p>
1041 <p>For the same reasons exclusions must come <em>before</em> the
1042 general <code class="directive">ProxyPass</code> directives.</p>
1046 <p>In Apache HTTP Server 2.1 and later, mod_proxy supports pooled
1047 connections to a backend server. Connections created on demand
1048 can be retained in a pool for future use. Limits on the pool size
1049 and other settings can be coded on
1050 the <code class="directive">ProxyPass</code> directive
1051 using <code>key=value</code> parameters, described in the table
1054 <p>By default, mod_proxy will allow and retain the maximum number of
1055 connections that could be used simultaneously by that web server child
1056 process. Use the <code>max</code> parameter to reduce the number from
1057 the default. Use the <code>ttl</code> parameter to set an optional
1058 time to live; connections which have been unused for at least
1059 <code>ttl</code> seconds will be closed. <code>ttl</code> can be used
1060 to avoid using a connection which is subject to closing because of the
1061 backend server's keep-alive timeout.</p>
1063 <p>The pool of connections is maintained per web server child
1064 process, and <code>max</code> and other settings are not coordinated
1065 among all child processes, except when only one child process is allowed
1066 by configuration or MPM design.</p>
1068 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">
1069 ProxyPass /example http://backend.example.com max=20 ttl=120 retry=300
1073 <table class="bordered"><tr><th>BalancerMember parameters</th></tr></table>
1075 <tr><th>Parameter</th>
1077 <th>Description</th></tr>
1080 <td>Minimum number of connection pool entries, unrelated to the
1081 actual number of connections. This only needs to be modified from the
1082 default for special circumstances where heap memory associated with the
1083 backend connections should be preallocated or retained.</td></tr>
1086 <td>Maximum number of connections that will be allowed to the
1087 backend server. The default for this limit is the number of threads
1088 per process in the active MPM. In the Prefork MPM, this is always 1,
1089 while with other MPMs it is controlled by the
1090 <code class="directive">ThreadsPerChild</code> directive.</td></tr>
1093 <td>Retained connection pool entries above this limit are freed
1094 during certain operations if they have been unused for longer than
1095 the time to live, controlled by the <code>ttl</code> parameter. If
1096 the connection pool entry has an associated connection, it will be
1097 closed. This only needs to be modified from the default for special
1098 circumstances where connection pool entries and any associated
1099 connections which have exceeded the time to live need to be freed or
1100 closed more aggressively.</td></tr>
1101 <tr><td>acquire</td>
1103 <td>If set this will be the maximum time to wait for a free
1104 connection in the connection pool, in milliseconds. If there are no free
1105 connections in the pool the Apache httpd will return <code>SERVER_BUSY</code>
1106 status to the client.
1108 <tr><td>connectiontimeout</td>
1110 <td>Connect timeout in seconds.
1111 The number of seconds Apache httpd waits for the creation of a connection to
1112 the backend to complete. By adding a postfix of ms the timeout can be
1113 also set in milliseconds.
1115 <tr><td>disablereuse</td>
1117 <td>This parameter should be used when you want to force mod_proxy
1118 to immediately close a connection to the backend after being used, and
1119 thus, disable its persistent connection and pool for that backend.
1120 This helps in various situations where a firewall between Apache
1122 the backend server (regardless of protocol) tends to silently
1123 drop connections or when backends themselves may be under round-
1124 robin DNS. To disable connection pooling reuse,
1125 set this property value to <code>On</code>.
1127 <tr><td>flushpackets</td>
1129 <td>Determines whether the proxy module will auto-flush the output
1130 brigade after each "chunk" of data. 'off' means that it will flush
1131 only when needed, 'on' means after each chunk is sent and
1132 'auto' means poll/wait for a period of time and flush if
1133 no input has been received for 'flushwait' milliseconds.
1134 Currently this is in effect only for AJP.
1136 <tr><td>flushwait</td>
1138 <td>The time to wait for additional input, in milliseconds, before
1139 flushing the output brigade if 'flushpackets' is 'auto'.
1141 <tr><td>iobuffersize</td>
1143 <td>Adjusts the size of the internal scratchpad IO buffer. This allows you
1144 to override the <code class="directive">ProxyIOBufferSize</code> for a specific worker.
1145 This must be at least 512 or set to 0 for the system default of 8192.
1147 <tr><td>keepalive</td>
1149 <td><p>This parameter should be used when you have a firewall between your
1150 Apache httpd and the backend server, who tend to drop inactive connections.
1151 This flag will tell the Operating System to send <code>KEEP_ALIVE</code>
1152 messages on inactive connections and thus prevent the firewall to drop the connection.
1153 To enable keepalive set this property value to <code>On</code>. </p>
1154 <p>The frequency of initial and subsequent TCP keepalive probes
1155 depends on global OS settings, and may be as high as 2 hours. To be useful,
1156 the frequency configured in the OS must be smaller than the threshold used
1157 by the firewall.</p>
1161 <td>Sets the load balancer cluster set that the worker is a member
1162 of. The load balancer will try all members of a lower numbered
1163 lbset before trying higher numbered ones.
1167 <td>Ping property tells the webserver to "test" the connection to
1168 the backend before forwarding the request. For AJP, it causes
1169 <code class="module"><a href="../mod/mod_proxy_ajp.html">mod_proxy_ajp</a></code>to send a <code>CPING</code>
1170 request on the ajp13 connection (implemented on Tomcat 3.3.2+, 4.1.28+
1171 and 5.0.13+). For HTTP, it causes <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code>
1172 to send a <code>100-Continue</code> to the backend (only valid for
1173 HTTP/1.1 - for non HTTP/1.1 backends, this property has no
1174 effect). In both cases the parameter is the delay in seconds to wait
1176 This feature has been added to avoid problems with hung and
1178 This will increase the network traffic during the normal operation
1179 which could be an issue, but it will lower the
1180 traffic in case some of the cluster nodes are down or busy.
1181 By adding a postfix of ms the delay can be also set in
1184 <tr><td>receivebuffersize</td>
1186 <td>Adjusts the size of the explicit (TCP/IP) network buffer size for
1187 proxied connections. This allows you to override the
1188 <code class="directive">ProxyReceiveBufferSize</code> for a specific worker.
1189 This must be at least 512 or set to 0 for the system default.
1191 <tr><td>redirect</td>
1193 <td>Redirection Route of the worker. This value is usually
1194 set dynamically to enable safe removal of the node from
1195 the cluster. If set all requests without session id will be
1196 redirected to the BalancerMember that has route parameter
1197 equal as this value.
1201 <td>Connection pool worker retry timeout in seconds.
1202 If the connection pool worker to the backend server is in the error state,
1203 Apache httpd will not forward any requests to that server until the timeout
1204 expires. This enables to shut down the backend server for maintenance,
1205 and bring it back online later. A value of 0 means always retry workers
1206 in an error state with no timeout.
1210 <td>Route of the worker when used inside load balancer.
1211 The route is a value appended to session id.
1215 <td>Single letter value defining the initial status of
1218 <tr><td>D: Worker is disabled and will not accept any requests.</td></tr>
1219 <tr><td>S: Worker is administratively stopped.</td></tr>
1220 <tr><td>I: Worker is in ignore-errors mode, and will always be considered available.</td></tr>
1221 <tr><td>H: Worker is in hot-standby mode and will only be used if no other
1222 viable workers are available.</td></tr>
1223 <tr><td>E: Worker is in an error state.</td></tr>
1224 <tr><td>N: Worker is in drain mode, and will only accept existing sticky sessions
1225 destined for itself and ignore all other requests.</td></tr>
1227 can be set (which is the default) by prepending with '+' or
1228 cleared by prepending with '-'.
1229 Thus, a setting of 'S-E' sets this worker to Stopped and
1230 clears the in-error flag.
1232 <tr><td>timeout</td>
1233 <td><code class="directive"><a href="#proxytimeout">ProxyTimeout</a></code></td>
1234 <td>Connection timeout in seconds.
1235 The number of seconds Apache httpd waits for data sent by / to the backend.
1239 <td>Time to live for inactive connections and associated connection
1240 pool entries, in seconds. Once reaching this limit, a
1241 connection will not be used again; it will be closed at some
1247 <p>If the Proxy directive scheme starts with the
1248 <code>balancer://</code> (eg: <code>balancer://cluster</code>,
1249 any path information is ignored) then a virtual worker that does not really
1250 communicate with the backend server will be created. Instead it is responsible
1251 for the management of several "real" workers. In that case the special set of
1252 parameters can be add to this virtual worker. See <code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code>
1253 for more information about how the balancer works.
1255 <table class="bordered"><tr><th>Balancer parameters</th></tr></table>
1257 <tr><th>Parameter</th>
1259 <th>Description</th></tr>
1260 <tr><td>lbmethod</td>
1262 <td>Balancer load-balance method. Select the load-balancing scheduler
1263 method to use. Either <code>byrequests</code>, to perform weighted
1264 request counting, <code>bytraffic</code>, to perform weighted
1265 traffic byte count balancing, or <code>bybusyness</code>, to perform
1266 pending request balancing. Default is <code>byrequests</code>.
1268 <tr><td>maxattempts</td>
1269 <td>One less than the number of workers, or 1 with a single worker.</td>
1270 <td>Maximum number of failover attempts before giving up.
1272 <tr><td>nofailover</td>
1274 <td>If set to <code>On</code> the session will break if the worker is in
1275 error state or disabled. Set this value to On if backend servers do not
1276 support session replication.
1278 <tr><td>stickysession</td>
1280 <td>Balancer sticky session name. The value is usually set to something
1281 like <code>JSESSIONID</code> or <code>PHPSESSIONID</code>,
1282 and it depends on the backend application server that support sessions.
1283 If the backend application server uses different name for cookies
1284 and url encoded id (like servlet containers) use | to to separate them.
1285 The first part is for the cookie the second for the path.
1287 <tr><td>stickysessionsep</td>
1289 <td>Sets the separation symbol in the session cookie. Some backend application servers
1290 do not use the '.' as the symbol. For example the Oracle Weblogic server uses
1291 '!'. The correct symbol can be set using this option. The setting of 'Off'
1292 signifies that no symbol is used.
1294 <tr><td>scolonpathdelim</td>
1296 <td>If set to <code>On</code> the semi-colon character ';' will be
1297 used as an additional sticky session path deliminator/separator. This
1298 is mainly used to emulate mod_jk's behavior when dealing with paths such
1299 as <code>JSESSIONID=6736bcf34;foo=aabfa</code>
1301 <tr><td>timeout</td>
1303 <td>Balancer timeout in seconds. If set this will be the maximum time
1304 to wait for a free worker. Default is not to wait.
1306 <tr><td>failonstatus</td>
1308 <td>A single or comma-separated list of HTTP status codes. If set this will
1309 force the worker into error state when the backend returns any status code
1310 in the list. Worker recovery behaves the same as other worker errors.
1313 <td><auto></td>
1314 <td>The protective nonce used in the <code>balancer-manager</code> application page.
1315 The default is to use an automatically determined UUID-based
1316 nonce, to provide for further protection for the page. If set,
1317 then the nonce is set to that value. A setting of <code>None</code>
1318 disables all nonce checking.
1319 <div class="note"><h3>Note</h3>
1320 <p>In addition to the nonce, the <code>balancer-manager</code> page
1321 should be protected via an ACL.</p>
1326 <td>Number of additional BalancerMembers to allow to be added
1327 to this balancer in addition to those defined at configuration.
1329 <tr><td>forcerecovery</td>
1331 <td>Force the immediate recovery of all workers without considering the
1332 retry parameter of the workers if all workers of a balancer are
1333 in error state. There might be cases where an already overloaded backend
1334 can get into deeper trouble if the recovery of all workers is enforced
1335 without considering the retry parameter of each worker. In this case
1336 set to <code>Off</code>.
1340 <p>A sample balancer setup</p>
1341 <pre class="prettyprint lang-config">
1342 ProxyPass /special-area http://special.example.com smax=5 max=10
1343 ProxyPass / balancer://mycluster/ stickysession=JSESSIONID|jsessionid nofailover=On
1344 <Proxy balancer://mycluster>
1345 BalancerMember ajp://1.2.3.4:8009
1346 BalancerMember ajp://1.2.3.5:8009 loadfactor=20
1347 # Less powerful server, don't send as many requests there,
1348 BalancerMember ajp://1.2.3.6:8009 loadfactor=5
1353 <p>Setting up a hot-standby, that will only be used if no other
1354 members are available</p>
1355 <pre class="prettyprint lang-config">
1356 ProxyPass / balancer://hotcluster/
1357 <Proxy balancer://hotcluster>
1358 BalancerMember ajp://1.2.3.4:8009 loadfactor=1
1359 BalancerMember ajp://1.2.3.5:8009 loadfactor=2
1360 # The server below is on hot standby
1361 BalancerMember ajp://1.2.3.6:8009 status=+H
1362 ProxySet lbmethod=bytraffic
1367 <p>Normally, mod_proxy will canonicalise ProxyPassed URLs.
1368 But this may be incompatible with some backends, particularly those
1369 that make use of <var>PATH_INFO</var>. The optional <var>nocanon</var>
1370 keyword suppresses this, and passes the URL path "raw" to the
1371 backend. Note that may affect the security of your backend, as it
1372 removes the normal limited protection against URL-based attacks
1373 provided by the proxy.</p>
1375 <p>The optional <var>interpolate</var> keyword (available in
1376 httpd 2.2.9 and later), in combination with
1377 <code class="directive">ProxyPassInterpolateEnv</code> causes the ProxyPass
1378 to interpolate environment variables, using the syntax
1379 <var>${VARNAME}</var>. Note that many of the standard CGI-derived
1380 environment variables will not exist when this interpolation happens,
1381 so you may still have to resort to <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>
1382 for complex rules.</p>
1384 <p>Normally, mod_proxy will include the query string when
1385 generating the <var>SCRIPT_FILENAME</var> environment variable.
1386 The optional <var>noquery</var> keyword (available in
1387 httpd 2.4.1 and later) prevents this.</p>
1389 <p>When used inside a <code class="directive"><a href="../mod/core.html#location"><Location></a></code> section, the first argument is omitted and the local
1390 directory is obtained from the <code class="directive"><a href="../mod/core.html#location"><Location></a></code>. The same will occur inside a
1391 <code class="directive"><a href="../mod/core.html#locationmatch"><LocationMatch></a></code> section,
1392 however ProxyPass does not interpret the regexp as such, so it is necessary
1393 to use <code class="directive">ProxyPassMatch</code> in this situation instead.</p>
1395 <p>This directive is not supported in <code class="directive"><a href="../mod/core.html#directory"><Directory></a></code> or <code class="directive"><a href="../mod/core.html#files"><Files></a></code> sections.</p>
1397 <p>If you require a more flexible reverse-proxy configuration, see the
1398 <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> directive with the
1399 <code>[P]</code> flag.</p>
1403 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1404 <div class="directive-section"><h2><a name="ProxyPassInterpolateEnv" id="ProxyPassInterpolateEnv">ProxyPassInterpolateEnv</a> <a name="proxypassinterpolateenv" id="proxypassinterpolateenv">Directive</a></h2>
1405 <table class="directive">
1406 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enable Environment Variable interpolation in Reverse Proxy configurations</td></tr>
1407 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassInterpolateEnv On|Off</code></td></tr>
1408 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyPassInterpolateEnv Off</code></td></tr>
1409 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1410 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1411 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1413 <p>This directive, together with the <var>interpolate</var> argument to
1414 <code class="directive">ProxyPass</code>, <code class="directive">ProxyPassReverse</code>,
1415 <code class="directive">ProxyPassReverseCookieDomain</code> and
1416 <code class="directive">ProxyPassReverseCookiePath</code>
1417 enables reverse proxies to be dynamically
1418 configured using environment variables, which may be set by
1419 another module such as <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>.
1420 It affects the <code class="directive">ProxyPass</code>,
1421 <code class="directive">ProxyPassReverse</code>,
1422 <code class="directive">ProxyPassReverseCookieDomain</code>, and
1423 <code class="directive">ProxyPassReverseCookiePath</code> directives,
1424 and causes them to substitute the value of an environment
1425 variable <code>varname</code> for the string <code>${varname}</code>
1426 in configuration directives (if the <var>interpolate</var> option is set).</p>
1427 <p>Keep this turned off (for server performance) unless you need it!</p>
1430 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1431 <div class="directive-section"><h2><a name="ProxyPassMatch" id="ProxyPassMatch">ProxyPassMatch</a> <a name="proxypassmatch" id="proxypassmatch">Directive</a></h2>
1432 <table class="directive">
1433 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maps remote servers into the local server URL-space using regular expressions</td></tr>
1434 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassMatch [<var>regex</var>] !|<var>url</var> [<var>key=value</var>
1435 <var>[key=value</var> ...]]</code></td></tr>
1436 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1437 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1438 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1440 <p>This directive is equivalent to <code class="directive"><a href="#proxypass">ProxyPass</a></code>,
1441 but makes use of regular expressions, instead of simple prefix matching. The
1442 supplied regular expression is matched against the <var>url</var>, and if it
1443 matches, the server will substitute any parenthesized matches into the given
1444 string and use it as a new <var>url</var>.</p>
1446 <p>Suppose the local server has address <code>http://example.com/</code>;
1449 <pre class="prettyprint lang-config">
1450 ProxyPassMatch ^(/.*\.gif)$ http://backend.example.com$1
1454 <p>will cause a local request for
1455 <code>http://example.com/foo/bar.gif</code> to be internally converted
1456 into a proxy request to <code>http://backend.example.com/foo/bar.gif</code>.</p>
1457 <div class="note"><h3>Note</h3>
1458 <p>The URL argument must be parsable as a URL <em>before</em> regexp
1459 substitutions (as well as after). This limits the matches you can use.
1460 For instance, if we had used</p>
1461 <pre class="prettyprint lang-config">
1462 ProxyPassMatch ^(/.*\.gif)$ http://backend.example.com:8000$1
1465 <p>in our previous example, it would fail with a syntax error
1466 at server startup. This is a bug (PR 46665 in the ASF bugzilla),
1467 and the workaround is to reformulate the match:</p>
1468 <pre class="prettyprint lang-config">
1469 ProxyPassMatch ^/(.*\.gif)$ http://backend.example.com:8000/$1
1473 <p>The <code>!</code> directive is useful in situations where you don't want
1474 to reverse-proxy a subdirectory.</p>
1476 <p>When used inside a <code class="directive"><a href="../mod/core.html#locationmatch"><LocationMatch></a></code> section, the first argument is omitted and the
1477 regexp is obtained from the <code class="directive"><a href="../mod/core.html#locationmatch"><LocationMatch></a></code>.</p>
1479 <p>If you require a more flexible reverse-proxy configuration, see the
1480 <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> directive with the
1481 <code>[P]</code> flag.</p>
1483 <div class="warning">
1484 <h3>Security Warning</h3>
1485 <p>Take care when constructing the target URL of the rule, considering
1486 the security impact from allowing the client influence over the set of
1487 URLs to which your server will act as a proxy. Ensure that the scheme
1488 and hostname part of the URL is either fixed, or does not allow the
1489 client undue influence.</p>
1493 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1494 <div class="directive-section"><h2><a name="ProxyPassReverse" id="ProxyPassReverse">ProxyPassReverse</a> <a name="proxypassreverse" id="proxypassreverse">Directive</a></h2>
1495 <table class="directive">
1496 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Adjusts the URL in HTTP response headers sent from a reverse
1497 proxied server</td></tr>
1498 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassReverse [<var>path</var>] <var>url</var>
1499 [<var>interpolate</var>]</code></td></tr>
1500 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1501 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1502 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1504 <p>This directive lets Apache httpd adjust the URL in the <code>Location</code>,
1505 <code>Content-Location</code> and <code>URI</code> headers on HTTP
1506 redirect responses. This is essential when Apache httpd is used as a
1507 reverse proxy (or gateway) to avoid by-passing the reverse proxy
1508 because of HTTP redirects on the backend servers which stay behind
1509 the reverse proxy.</p>
1511 <p>Only the HTTP response headers specifically mentioned above
1512 will be rewritten. Apache httpd will not rewrite other response
1513 headers, nor will it by default rewrite URL references inside HTML pages.
1514 This means that if the proxied content contains absolute URL
1515 references, they will by-pass the proxy. To rewrite HTML content to
1516 match the proxy, you must load and enable <code class="module"><a href="../mod/mod_proxy_html.html">mod_proxy_html</a></code>.
1519 <p><var>path</var> is the name of a local virtual path. <var>url</var> is a
1520 partial URL for the remote server - the same way they are used for the
1521 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.</p>
1523 <p>For example, suppose the local server has address
1524 <code>http://example.com/</code>; then</p>
1526 <pre class="prettyprint lang-config">
1527 ProxyPass /mirror/foo/ http://backend.example.com/
1528 ProxyPassReverse /mirror/foo/ http://backend.example.com/
1529 ProxyPassReverseCookieDomain backend.example.com public.example.com
1530 ProxyPassReverseCookiePath / /mirror/foo/
1534 <p>will not only cause a local request for the
1535 <code>http://example.com/mirror/foo/bar</code> to be internally converted
1536 into a proxy request to <code>http://backend.example.com/bar</code>
1537 (the functionality <code>ProxyPass</code> provides here). It also takes care
1538 of redirects the server <code>backend.example.com</code> sends: when
1539 <code>http://backend.example.com/bar</code> is redirected by him to
1540 <code>http://backend.example.com/quux</code> Apache httpd adjusts this to
1541 <code>http://example.com/mirror/foo/quux</code> before forwarding the HTTP
1542 redirect response to the client. Note that the hostname used for
1543 constructing the URL is chosen in respect to the setting of the <code class="directive"><a href="../mod/core.html#usecanonicalname">UseCanonicalName</a></code> directive.</p>
1545 <p>Note that this <code class="directive">ProxyPassReverse</code> directive can
1546 also be used in conjunction with the proxy pass-through feature
1547 (<code>RewriteRule ... [P]</code>) from <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>
1548 because it doesn't depend on a corresponding <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.</p>
1550 <p>The optional <var>interpolate</var> keyword (available in
1551 httpd 2.2.9 and later), used together with
1552 <code class="directive">ProxyPassInterpolateEnv</code>, enables interpolation
1553 of environment variables specified using the format <var>${VARNAME}</var>.
1556 <p>When used inside a <code class="directive"><a href="../mod/core.html#location"><Location></a></code> section, the first argument is omitted and the local
1557 directory is obtained from the <code class="directive"><a href="../mod/core.html#location"><Location></a></code>. The same occurs inside a <code class="directive"><a href="../mod/core.html#locationmatch"><LocationMatch></a></code> section, but will probably not work as
1558 intended, as ProxyPassReverse will interpret the regexp literally as a
1559 path; if needed in this situation, specify the ProxyPassReverse outside
1560 the section, or in a separate <code class="directive"><a href="../mod/core.html#location"><Location></a></code> section.</p>
1562 <p>This directive is not supported in <code class="directive"><a href="../mod/core.html#directory"><Directory></a></code> or <code class="directive"><a href="../mod/core.html#files"><Files></a></code> sections.</p>
1565 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1566 <div class="directive-section"><h2><a name="ProxyPassReverseCookieDomain" id="ProxyPassReverseCookieDomain">ProxyPassReverseCookieDomain</a> <a name="proxypassreversecookiedomain" id="proxypassreversecookiedomain">Directive</a></h2>
1567 <table class="directive">
1568 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Adjusts the Domain string in Set-Cookie headers from a reverse-
1569 proxied server</td></tr>
1570 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassReverseCookieDomain <var>internal-domain</var>
1571 <var>public-domain</var> [<var>interpolate</var>]</code></td></tr>
1572 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1573 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1574 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1576 <p>Usage is basically similar to
1577 <code class="directive"><a href="#proxypassreverse">ProxyPassReverse</a></code>, but instead of
1578 rewriting headers that are a URL, this rewrites the <code>domain</code>
1579 string in <code>Set-Cookie</code> headers.</p>
1582 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1583 <div class="directive-section"><h2><a name="ProxyPassReverseCookiePath" id="ProxyPassReverseCookiePath">ProxyPassReverseCookiePath</a> <a name="proxypassreversecookiepath" id="proxypassreversecookiepath">Directive</a></h2>
1584 <table class="directive">
1585 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Adjusts the Path string in Set-Cookie headers from a reverse-
1586 proxied server</td></tr>
1587 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassReverseCookiePath <var>internal-path</var>
1588 <var>public-path</var> [<var>interpolate</var>]</code></td></tr>
1589 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1590 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1591 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1594 Useful in conjunction with
1595 <code class="directive"><a href="#proxypassreverse">ProxyPassReverse</a></code>
1596 in situations where backend URL paths are mapped to public paths on the
1597 reverse proxy. This directive rewrites the <code>path</code> string in
1598 <code>Set-Cookie</code> headers. If the beginning of the cookie path matches
1599 <var>internal-path</var>, the cookie path will be replaced with
1600 <var>public-path</var>.
1602 In the example given with
1603 <code class="directive"><a href="#proxypassreverse">ProxyPassReverse</a></code>, the directive:
1605 <pre class="prettyprint lang-config">
1606 ProxyPassReverseCookiePath / /mirror/foo/
1610 will rewrite a cookie with backend path <code>/</code> (or
1611 <code>/example</code> or, in fact, anything) to <code>/mirror/foo/</code>.
1615 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1616 <div class="directive-section"><h2><a name="ProxyPreserveHost" id="ProxyPreserveHost">ProxyPreserveHost</a> <a name="proxypreservehost" id="proxypreservehost">Directive</a></h2>
1617 <table class="directive">
1618 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Use incoming Host HTTP request header for proxy
1620 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPreserveHost On|Off</code></td></tr>
1621 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyPreserveHost Off</code></td></tr>
1622 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1623 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1624 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1625 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Usable in directory
1626 context in 2.3.3 and later.</td></tr>
1628 <p>When enabled, this option will pass the Host: line from the incoming
1629 request to the proxied host, instead of the hostname specified in the
1630 <code class="directive">ProxyPass</code> line.</p>
1632 <p>This option should normally be turned <code>Off</code>. It is mostly
1633 useful in special configurations like proxied mass name-based virtual
1634 hosting, where the original Host header needs to be evaluated by the
1638 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1639 <div class="directive-section"><h2><a name="ProxyReceiveBufferSize" id="ProxyReceiveBufferSize">ProxyReceiveBufferSize</a> <a name="proxyreceivebuffersize" id="proxyreceivebuffersize">Directive</a></h2>
1640 <table class="directive">
1641 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Network buffer size for proxied HTTP and FTP
1642 connections</td></tr>
1643 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyReceiveBufferSize <var>bytes</var></code></td></tr>
1644 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyReceiveBufferSize 0</code></td></tr>
1645 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1646 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1647 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1649 <p>The <code class="directive">ProxyReceiveBufferSize</code> directive specifies an
1650 explicit (TCP/IP) network buffer size for proxied HTTP and FTP connections,
1651 for increased throughput. It has to be greater than <code>512</code> or set
1652 to <code>0</code> to indicate that the system's default buffer size should
1655 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">
1656 ProxyReceiveBufferSize 2048
1661 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1662 <div class="directive-section"><h2><a name="ProxyRemote" id="ProxyRemote">ProxyRemote</a> <a name="proxyremote" id="proxyremote">Directive</a></h2>
1663 <table class="directive">
1664 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Remote proxy used to handle certain requests</td></tr>
1665 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyRemote <var>match</var> <var>remote-server</var></code></td></tr>
1666 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1667 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1668 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1670 <p>This defines remote proxies to this proxy. <var>match</var> is either the
1671 name of a URL-scheme that the remote server supports, or a partial URL
1672 for which the remote server should be used, or <code>*</code> to indicate
1673 the server should be contacted for all requests. <var>remote-server</var> is
1674 a partial URL for the remote server. Syntax:</p>
1676 <div class="example"><p><code>
1677 <dfn>remote-server</dfn> =
1678 <var>scheme</var>://<var>hostname</var>[:<var>port</var>]
1681 <p><var>scheme</var> is effectively the protocol that should be used to
1682 communicate with the remote server; only <code>http</code> and <code>https</code>
1683 are supported by this module. When using <code>https</code>, the requests
1684 are forwarded through the remote proxy using the HTTP CONNECT method.</p>
1686 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">
1687 ProxyRemote http://goodguys.example.com/ http://mirrorguys.example.com:8000
1688 ProxyRemote * http://cleverproxy.localdomain
1689 ProxyRemote ftp http://ftpproxy.mydomain:8080
1693 <p>In the last example, the proxy will forward FTP requests, encapsulated
1694 as yet another HTTP proxy request, to another proxy which can handle
1697 <p>This option also supports reverse proxy configuration - a backend
1698 webserver can be embedded within a virtualhost URL space even if that
1699 server is hidden by another forward proxy.</p>
1702 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1703 <div class="directive-section"><h2><a name="ProxyRemoteMatch" id="ProxyRemoteMatch">ProxyRemoteMatch</a> <a name="proxyremotematch" id="proxyremotematch">Directive</a></h2>
1704 <table class="directive">
1705 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Remote proxy used to handle requests matched by regular
1706 expressions</td></tr>
1707 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyRemoteMatch <var>regex</var> <var>remote-server</var></code></td></tr>
1708 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1709 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1710 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1712 <p>The <code class="directive">ProxyRemoteMatch</code> is identical to the
1713 <code class="directive"><a href="#proxyremote">ProxyRemote</a></code> directive, except the
1714 first argument is a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>
1715 match against the requested URL.</p>
1718 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1719 <div class="directive-section"><h2><a name="ProxyRequests" id="ProxyRequests">ProxyRequests</a> <a name="proxyrequests" id="proxyrequests">Directive</a></h2>
1720 <table class="directive">
1721 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables forward (standard) proxy requests</td></tr>
1722 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyRequests On|Off</code></td></tr>
1723 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyRequests Off</code></td></tr>
1724 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1725 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1726 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1728 <p>This allows or prevents Apache httpd from functioning as a forward proxy
1729 server. (Setting ProxyRequests to <code>Off</code> does not disable use of
1730 the <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.)</p>
1732 <p>In a typical reverse proxy or gateway configuration, this
1733 option should be set to
1734 <code>Off</code>.</p>
1736 <p>In order to get the functionality of proxying HTTP or FTP sites, you
1737 need also <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code> or <code class="module"><a href="../mod/mod_proxy_ftp.html">mod_proxy_ftp</a></code>
1738 (or both) present in the server.</p>
1740 <p>In order to get the functionality of (forward) proxying HTTPS sites, you
1741 need <code class="module"><a href="../mod/mod_proxy_connect.html">mod_proxy_connect</a></code> enabled in the server.</p>
1743 <div class="warning"><h3>Warning</h3>
1744 <p>Do not enable proxying with <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> until you have <a href="#access">secured your server</a>. Open proxy servers are dangerous
1745 both to your network and to the Internet at large.</p>
1750 <li><a href="#forwardreverse">Forward and Reverse Proxies/Gateways</a></li>
1753 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1754 <div class="directive-section"><h2><a name="ProxySet" id="ProxySet">ProxySet</a> <a name="proxyset" id="proxyset">Directive</a></h2>
1755 <table class="directive">
1756 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Set various Proxy balancer or member parameters</td></tr>
1757 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxySet <var>url</var> <var>key=value [key=value ...]</var></code></td></tr>
1758 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
1759 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1760 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1762 <p>This directive is used as an alternate method of setting any of the
1763 parameters available to Proxy balancers and workers normally done via the
1764 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive. If used
1765 within a <code><Proxy <var>balancer url|worker url</var>></code>
1766 container directive, the <var>url</var> argument is not required. As a side
1767 effect the respective balancer or worker gets created. This can be useful
1768 when doing reverse proxying via a
1769 <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> instead of a
1770 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.</p>
1772 <div class="example"><pre class="prettyprint lang-config">
1773 <Proxy balancer://hotcluster>
1774 BalancerMember http://www2.example.com:8080 loadfactor=1
1775 BalancerMember http://www3.example.com:8080 loadfactor=2
1776 ProxySet lbmethod=bytraffic
1781 <pre class="prettyprint lang-config">
1782 <Proxy http://backend>
1783 ProxySet keepalive=On
1788 <pre class="prettyprint lang-config">
1789 ProxySet balancer://foo lbmethod=bytraffic timeout=15
1793 <pre class="prettyprint lang-config">
1794 ProxySet ajp://backend:7001 timeout=15
1798 <div class="warning"><h3>Warning</h3>
1799 <p>Keep in mind that the same parameter key can have a different meaning
1800 depending whether it is applied to a balancer or a worker as shown by the two
1801 examples above regarding timeout.</p>
1806 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1807 <div class="directive-section"><h2><a name="ProxySourceAddress" id="ProxySourceAddress">ProxySourceAddress</a> <a name="proxysourceaddress" id="proxysourceaddress">Directive</a></h2>
1808 <table class="directive">
1809 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Set local IP address for outgoing proxy connections</td></tr>
1810 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxySourceAddress <var>address</var></code></td></tr>
1811 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1812 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1813 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1814 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in version 2.3.9 and later</td></tr>
1816 <p>This directive allows to set a specific local address to bind to when connecting
1817 to a backend server.</p>
1820 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1821 <div class="directive-section"><h2><a name="ProxyStatus" id="ProxyStatus">ProxyStatus</a> <a name="proxystatus" id="proxystatus">Directive</a></h2>
1822 <table class="directive">
1823 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Show Proxy LoadBalancer status in mod_status</td></tr>
1824 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyStatus Off|On|Full</code></td></tr>
1825 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyStatus Off</code></td></tr>
1826 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1827 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1828 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1830 <p>This directive determines whether or not proxy
1831 loadbalancer status data is displayed via the <code class="module"><a href="../mod/mod_status.html">mod_status</a></code>
1832 server-status page.</p>
1833 <div class="note"><h3>Note</h3>
1834 <p><strong>Full</strong> is synonymous with <strong>On</strong></p>
1839 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1840 <div class="directive-section"><h2><a name="ProxyTimeout" id="ProxyTimeout">ProxyTimeout</a> <a name="proxytimeout" id="proxytimeout">Directive</a></h2>
1841 <table class="directive">
1842 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Network timeout for proxied requests</td></tr>
1843 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyTimeout <var>seconds</var></code></td></tr>
1844 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Value of <code class="directive"><a href="../mod/core.html#timeout">Timeout</a></code></code></td></tr>
1845 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1846 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1847 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1849 <p>This directive allows a user to specifiy a timeout on proxy requests.
1850 This is useful when you have a slow/buggy appserver which hangs, and you
1851 would rather just return a timeout and fail gracefully instead of waiting
1852 however long it takes the server to return.</p>
1855 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1856 <div class="directive-section"><h2><a name="ProxyVia" id="ProxyVia">ProxyVia</a> <a name="proxyvia" id="proxyvia">Directive</a></h2>
1857 <table class="directive">
1858 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Information provided in the <code>Via</code> HTTP response
1859 header for proxied requests</td></tr>
1860 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyVia On|Off|Full|Block</code></td></tr>
1861 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyVia Off</code></td></tr>
1862 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1863 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1864 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1866 <p>This directive controls the use of the <code>Via:</code> HTTP
1867 header by the proxy. Its intended use is to control the flow of
1868 proxy requests along a chain of proxy servers. See <a href="http://www.ietf.org/rfc/rfc2616.txt">RFC 2616</a> (HTTP/1.1), section
1869 14.45 for an explanation of <code>Via:</code> header lines.</p>
1872 <li>If set to <code>Off</code>, which is the default, no special processing
1873 is performed. If a request or reply contains a <code>Via:</code> header,
1874 it is passed through unchanged.</li>
1876 <li>If set to <code>On</code>, each request and reply will get a
1877 <code>Via:</code> header line added for the current host.</li>
1879 <li>If set to <code>Full</code>, each generated <code>Via:</code> header
1880 line will additionally have the Apache httpd server version shown as a
1881 <code>Via:</code> comment field.</li>
1883 <li>If set to <code>Block</code>, every proxy request will have all its
1884 <code>Via:</code> header lines removed. No new <code>Via:</code> header will
1890 <div class="bottomlang">
1891 <p><span>Available Languages: </span><a href="../en/mod/mod_proxy.html" title="English"> en </a> |
1892 <a href="../fr/mod/mod_proxy.html" hreflang="fr" rel="alternate" title="Français"> fr </a> |
1893 <a href="../ja/mod/mod_proxy.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a></p>
1894 </div><div class="top"><a href="#page-header"><img src="../images/up.gif" alt="top" /></a></div><div class="section"><h2><a id="comments_section" name="comments_section">Comments</a></h2><div class="warning"><strong>Notice:</strong><br />This is not a Q&A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed again by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Freenode, or sent to our <a href="http://httpd.apache.org/lists.html">mailing lists</a>.</div>
1895 <script type="text/javascript"><!--//--><![CDATA[//><!--
1896 var comments_shortname = 'httpd';
1897 var comments_identifier = 'http://httpd.apache.org/docs/trunk/mod/mod_proxy.html';
1899 if (w.location.hostname.toLowerCase() == "httpd.apache.org") {
1900 d.write('<div id="comments_thread"><\/div>');
1901 var s = d.createElement('script');
1902 s.type = 'text/javascript';
1904 s.src = 'https://comments.apache.org/show_comments.lua?site=' + comments_shortname + '&page=' + comments_identifier;
1905 (d.getElementsByTagName('head')[0] || d.getElementsByTagName('body')[0]).appendChild(s);
1908 d.write('<div id="comments_thread">Comments are disabled for this page at the moment.<\/div>');
1910 })(window, document);
1911 //--><!]]></script></div><div id="footer">
1912 <p class="apache">Copyright 2012 The Apache Software Foundation.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p>
1913 <p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p></div><script type="text/javascript"><!--//--><![CDATA[//><!--
1914 if (typeof(prettyPrint) !== 'undefined') {