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/quickreference.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="#proxypassinherit">ProxyPassInherit</a></li>
104 <li><img alt="" src="../images/down.gif" /> <a href="#proxypassinterpolateenv">ProxyPassInterpolateEnv</a></li>
105 <li><img alt="" src="../images/down.gif" /> <a href="#proxypassmatch">ProxyPassMatch</a></li>
106 <li><img alt="" src="../images/down.gif" /> <a href="#proxypassreverse">ProxyPassReverse</a></li>
107 <li><img alt="" src="../images/down.gif" /> <a href="#proxypassreversecookiedomain">ProxyPassReverseCookieDomain</a></li>
108 <li><img alt="" src="../images/down.gif" /> <a href="#proxypassreversecookiepath">ProxyPassReverseCookiePath</a></li>
109 <li><img alt="" src="../images/down.gif" /> <a href="#proxypreservehost">ProxyPreserveHost</a></li>
110 <li><img alt="" src="../images/down.gif" /> <a href="#proxyreceivebuffersize">ProxyReceiveBufferSize</a></li>
111 <li><img alt="" src="../images/down.gif" /> <a href="#proxyremote">ProxyRemote</a></li>
112 <li><img alt="" src="../images/down.gif" /> <a href="#proxyremotematch">ProxyRemoteMatch</a></li>
113 <li><img alt="" src="../images/down.gif" /> <a href="#proxyrequests">ProxyRequests</a></li>
114 <li><img alt="" src="../images/down.gif" /> <a href="#proxyset">ProxySet</a></li>
115 <li><img alt="" src="../images/down.gif" /> <a href="#proxysourceaddress">ProxySourceAddress</a></li>
116 <li><img alt="" src="../images/down.gif" /> <a href="#proxystatus">ProxyStatus</a></li>
117 <li><img alt="" src="../images/down.gif" /> <a href="#proxytimeout">ProxyTimeout</a></li>
118 <li><img alt="" src="../images/down.gif" /> <a href="#proxyvia">ProxyVia</a></li>
122 <li><img alt="" src="../images/down.gif" /> <a href="#forwardreverse">Forward Proxies and Reverse
123 Proxies/Gateways</a></li>
124 <li><img alt="" src="../images/down.gif" /> <a href="#examples">Basic Examples</a></li>
125 <li><img alt="" src="../images/down.gif" /> <a href="#workers">Workers</a></li>
126 <li><img alt="" src="../images/down.gif" /> <a href="#access">Controlling access to your proxy</a></li>
127 <li><img alt="" src="../images/down.gif" /> <a href="#startup">Slow Startup</a></li>
128 <li><img alt="" src="../images/down.gif" /> <a href="#intranet">Intranet Proxy</a></li>
129 <li><img alt="" src="../images/down.gif" /> <a href="#envsettings">Protocol Adjustments</a></li>
130 <li><img alt="" src="../images/down.gif" /> <a href="#request-bodies">Request Bodies</a></li>
131 <li><img alt="" src="../images/down.gif" /> <a href="#x-headers">Reverse Proxy Request Headers</a></li>
132 </ul><h3>See also</h3>
134 <li><code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code></li>
135 <li><code class="module"><a href="../mod/mod_proxy_ajp.html">mod_proxy_ajp</a></code></li>
136 <li><code class="module"><a href="../mod/mod_proxy_connect.html">mod_proxy_connect</a></code></li>
137 <li><code class="module"><a href="../mod/mod_proxy_fcgi.html">mod_proxy_fcgi</a></code></li>
138 <li><code class="module"><a href="../mod/mod_proxy_ftp.html">mod_proxy_ftp</a></code></li>
139 <li><code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code></li>
140 <li><code class="module"><a href="../mod/mod_proxy_scgi.html">mod_proxy_scgi</a></code></li>
141 <li><code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code></li>
142 <li><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></li>
143 </ul><ul class="seealso"><li><a href="#comments_section">Comments</a></li></ul></div>
144 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
145 <div class="section">
146 <h2><a name="forwardreverse" id="forwardreverse">Forward Proxies and Reverse
147 Proxies/Gateways</a></h2>
148 <p>Apache HTTP Server can be configured in both a <dfn>forward</dfn> and
149 <dfn>reverse</dfn> proxy (also known as <dfn>gateway</dfn>) mode.</p>
151 <p>An ordinary <dfn>forward proxy</dfn> is an intermediate
152 server that sits between the client and the <em>origin
153 server</em>. In order to get content from the origin server,
154 the client sends a request to the proxy naming the origin server
155 as the target and the proxy then requests the content from the
156 origin server and returns it to the client. The client must be
157 specially configured to use the forward proxy to access other
160 <p>A typical usage of a forward proxy is to provide Internet
161 access to internal clients that are otherwise restricted by a
162 firewall. The forward proxy can also use caching (as provided
163 by <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code>) to reduce network usage.</p>
165 <p>The forward proxy is activated using the <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> directive. Because
166 forward proxies allow clients to access arbitrary sites through
167 your server and to hide their true origin, it is essential that
168 you <a href="#access">secure your server</a> so that only
169 authorized clients can access the proxy before activating a
172 <p>A <dfn>reverse proxy</dfn> (or <dfn>gateway</dfn>), by
173 contrast, appears to the client just like an ordinary web
174 server. No special configuration on the client is necessary.
175 The client makes ordinary requests for content in the name-space
176 of the reverse proxy. The reverse proxy then decides where to
177 send those requests, and returns the content as if it was itself
180 <p>A typical usage of a reverse proxy is to provide Internet
181 users access to a server that is behind a firewall. Reverse
182 proxies can also be used to balance load among several back-end
183 servers, or to provide caching for a slower back-end server.
184 In addition, reverse proxies can be used simply to bring
185 several servers into the same URL space.</p>
187 <p>A reverse proxy is activated using the <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive or the
188 <code>[P]</code> flag to the <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> directive. It is
189 <strong>not</strong> necessary to turn <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> on in order to
190 configure a reverse proxy.</p>
191 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
192 <div class="section">
193 <h2><a name="examples" id="examples">Basic Examples</a></h2>
195 <p>The examples below are only a very basic idea to help you
196 get started. Please read the documentation on the individual
199 <p>In addition, if you wish to have caching enabled, consult
200 the documentation from <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code>.</p>
202 <div class="example"><h3>Reverse Proxy</h3><pre class="prettyprint lang-config">
203 ProxyPass /foo http://foo.example.com/bar
204 ProxyPassReverse /foo http://foo.example.com/bar
208 <div class="example"><h3>Forward Proxy</h3><pre class="prettyprint lang-config">
213 Require host internal.example.com
217 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
218 <div class="section">
219 <h2><a name="workers" id="workers">Workers</a></h2>
220 <p>The proxy manages the configuration of origin servers and their
221 communication parameters in objects called <dfn>workers</dfn>.
222 There are two built-in workers, the default forward proxy worker and the
223 default reverse proxy worker. Additional workers can be configured
226 <p>The two default workers have a fixed configuration
227 and will be used if no other worker matches the request.
228 They do not use HTTP Keep-Alive or connection pooling.
229 The TCP connections to the origin server will instead be
230 opened and closed for each request.</p>
232 <p>Explicitly configured workers are identified by their URL.
233 They are usually created and configured using
234 <code class="directive"><a href="#proxypass">ProxyPass</a></code> or
235 <code class="directive"><a href="#proxypassmatch">ProxyPassMatch</a></code> when used
236 for a reverse proxy:</p>
238 <pre class="prettyprint lang-config">
239 ProxyPass /example http://backend.example.com connectiontimeout=5 timeout=30
243 <p>This will create a worker associated with the origin server URL
244 <code>http://backend.example.com</code> and using the given timeout
245 values. When used in a forward proxy, workers are usually defined
246 via the <code class="directive"><a href="#proxyset">ProxySet</a></code> directive:</p>
248 <pre class="prettyprint lang-config">
249 ProxySet http://backend.example.com connectiontimeout=5 timeout=30
253 <p>or alternatively using <code class="directive"><a href="#proxy">Proxy</a></code>
254 and <code class="directive"><a href="#proxyset">ProxySet</a></code>:</p>
256 <pre class="prettyprint lang-config">
257 <Proxy http://backend.example.com>
258 ProxySet connectiontimeout=5 timeout=30
263 <p>Using explicitly configured workers in the forward mode is
264 not very common, because forward proxies usually communicate with many
265 different origin servers. Creating explicit workers for some of the
266 origin servers can still be useful, if they are used very often.
267 Explicitly configured workers have no concept of forward or reverse
268 proxying by themselves. They encapsulate a common concept of
269 communication with origin servers. A worker created by
270 <code class="directive"><a href="#proxypass">ProxyPass</a></code> for use in a
271 reverse proxy will be also used for forward proxy requests whenever
272 the URL to the origin server matches the worker URL and vice versa.</p>
274 <p>The URL identifying a direct worker is the URL of its
275 origin server including any path components given:</p>
277 <pre class="prettyprint lang-config">
278 ProxyPass /examples http://backend.example.com/examples
279 ProxyPass /docs http://backend.example.com/docs
283 <p>This example defines two different workers, each using a separate
284 connection pool and configuration.</p>
286 <div class="warning"><h3>Worker Sharing</h3>
287 <p>Worker sharing happens if the worker URLs overlap, which occurs when
288 the URL of some worker is a leading substring of the URL of another
289 worker defined later in the configuration file. In the following example</p>
291 <pre class="prettyprint lang-config">
292 ProxyPass /apps http://backend.example.com/ timeout=60
293 ProxyPass /examples http://backend.example.com/examples timeout=10
297 <p>the second worker isn't actually created. Instead the first
298 worker is used. The benefit is, that there is only one connection pool,
299 so connections are more often reused. Note that all configuration attributes
300 given explicitly for the later worker will be ignored. This will be logged
301 as a warning. In the above example the resulting timeout value
302 for the URL <code>/examples</code> will be <code>60</code> instead
303 of <code>10</code>!</p>
305 <p>If you want to avoid worker sharing, sort your worker definitions
306 by URL length, starting with the longest worker URLs. If you want to maximize
307 worker sharing use the reverse sort order. See also the related warning about
308 ordering <code class="directive"><a href="#proxypass">ProxyPass</a></code> directives.</p>
312 <p>Explicitly configured workers come in two flavors:
313 <dfn>direct workers</dfn> and <dfn>(load) balancer workers</dfn>.
314 They support many important configuration attributes which are
315 described below in the <code class="directive"><a href="#proxypass">ProxyPass</a></code>
316 directive. The same attributes can also be set using
317 <code class="directive"><a href="#proxyset">ProxySet</a></code>.</p>
319 <p>The set of options available for a direct worker
320 depends on the protocol, which is specified in the origin server URL.
321 Available protocols include <code>ajp</code>, <code>fcgi</code>,
322 <code>ftp</code>, <code>http</code> and <code>scgi</code>.</p>
324 <p>Balancer workers are virtual workers that use direct workers known
325 as their members to actually handle the requests. Each balancer can
326 have multiple members. When it handles a request, it chooses a member
327 based on the configured load balancing algorithm.</p>
329 <p>A balancer worker is created if its worker URL uses
330 <code>balancer</code> as the protocol scheme.
331 The balancer URL uniquely identifies the balancer worker.
332 Members are added to a balancer using
333 <code class="directive"><a href="#balancermember">BalancerMember</a></code>.</p>
335 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
336 <div class="section">
337 <h2><a name="access" id="access">Controlling access to your proxy</a></h2>
338 <p>You can control who can access your proxy via the <code class="directive"><a href="#proxy"><Proxy></a></code> control block as in
339 the following example:</p>
341 <pre class="prettyprint lang-config">
348 <p>For more information on access control directives, see
349 <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code>.</p>
351 <p>Strictly limiting access is essential if you are using a
352 forward proxy (using the <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> directive).
353 Otherwise, your server can be used by any client to access
354 arbitrary hosts while hiding his or her true identity. This is
355 dangerous both for your network and for the Internet at large.
356 When using a reverse proxy (using the <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive with
357 <code>ProxyRequests Off</code>), access control is less
358 critical because clients can only contact the hosts that you
359 have specifically configured.</p>
361 <p><strong>See Also</strong> the <a href="mod_proxy_http.html#env">Proxy-Chain-Auth</a> environment variable.</p>
363 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
364 <div class="section">
365 <h2><a name="startup" id="startup">Slow Startup</a></h2>
366 <p>If you're using the <code class="directive"><a href="#proxyblock">ProxyBlock</a></code> directive, hostnames' IP addresses are looked up
367 and cached during startup for later match test. This may take a few
368 seconds (or more) depending on the speed with which the hostname lookups
370 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
371 <div class="section">
372 <h2><a name="intranet" id="intranet">Intranet Proxy</a></h2>
373 <p>An Apache httpd proxy server situated in an intranet needs to forward
374 external requests through the company's firewall (for this, configure
375 the <code class="directive"><a href="#proxyremote">ProxyRemote</a></code> directive
376 to forward the respective <var>scheme</var> to the firewall proxy).
377 However, when it has to
378 access resources within the intranet, it can bypass the firewall when
379 accessing hosts. The <code class="directive"><a href="#noproxy">NoProxy</a></code>
380 directive is useful for specifying which hosts belong to the intranet and
381 should be accessed directly.</p>
383 <p>Users within an intranet tend to omit the local domain name from their
384 WWW requests, thus requesting "http://somehost/" instead of
385 <code>http://somehost.example.com/</code>. Some commercial proxy servers
386 let them get away with this and simply serve the request, implying a
387 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
388 a redirect response and send the client to the correct, fully qualified,
389 server address. This is the preferred method since the user's bookmark
390 files will then contain fully qualified hosts.</p>
391 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
392 <div class="section">
393 <h2><a name="envsettings" id="envsettings">Protocol Adjustments</a></h2>
394 <p>For circumstances where <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> is sending
395 requests to an origin server that doesn't properly implement
396 keepalives or HTTP/1.1, there are two <a href="../env.html">environment variables</a> that can force the
397 request to use HTTP/1.0 with no keepalive. These are set via the
398 <code class="directive"><a href="../mod/mod_env.html#setenv">SetEnv</a></code> directive.</p>
400 <p>These are the <code>force-proxy-request-1.0</code> and
401 <code>proxy-nokeepalive</code> notes.</p>
403 <pre class="prettyprint lang-config">
404 <Location /buggyappserver/>
405 ProxyPass http://buggyappserver:7001/foo/
406 SetEnv force-proxy-request-1.0 1
407 SetEnv proxy-nokeepalive 1
412 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
413 <div class="section">
414 <h2><a name="request-bodies" id="request-bodies">Request Bodies</a></h2>
416 <p>Some request methods such as POST include a request body.
417 The HTTP protocol requires that requests which include a body
418 either use chunked transfer encoding or send a
419 <code>Content-Length</code> request header. When passing these
420 requests on to the origin server, <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code>
421 will always attempt to send the <code>Content-Length</code>. But
422 if the body is large and the original request used chunked
423 encoding, then chunked encoding may also be used in the upstream
424 request. You can control this selection using <a href="../env.html">environment variables</a>. Setting
425 <code>proxy-sendcl</code> ensures maximum compatibility with
426 upstream servers by always sending the
427 <code>Content-Length</code>, while setting
428 <code>proxy-sendchunked</code> minimizes resource usage by using
429 chunked encoding.</p>
431 <p>Under some circumstances, the server must spool request bodies
432 to disk to satisfy the requested handling of request bodies. For
433 example, this spooling will occur if the original body was sent with
434 chunked encoding (and is large), but the administrator has
435 asked for backend requests to be sent with Content-Length or as HTTP/1.0.
436 This spooling can also occur if the request body already has a
437 Content-Length header, but the server is configured to filter incoming
440 <p><code class="directive"><a href="../mod/core.html#limitrequestbody">LimitRequestBody</a></code> only applies to
441 request bodies that the server will spool to disk</p>
443 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
444 <div class="section">
445 <h2><a name="x-headers" id="x-headers">Reverse Proxy Request Headers</a></h2>
447 <p>When acting in a reverse-proxy mode (using the <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive, for example),
448 <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code> adds several request headers in
449 order to pass information to the origin server. These headers
453 <dt><code>X-Forwarded-For</code></dt>
454 <dd>The IP address of the client.</dd>
455 <dt><code>X-Forwarded-Host</code></dt>
456 <dd>The original host requested by the client in the <code>Host</code>
457 HTTP request header.</dd>
458 <dt><code>X-Forwarded-Server</code></dt>
459 <dd>The hostname of the proxy server.</dd>
462 <p>Be careful when using these headers on the origin server, since
463 they will contain more than one (comma-separated) value if the
464 original request already contained one of these headers. For
465 example, you can use <code>%{X-Forwarded-For}i</code> in the log
466 format string of the origin server to log the original clients IP
467 address, but you may get more than one address if the request
468 passes through several proxies.</p>
470 <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
471 other request headers.</p>
474 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
475 <div class="directive-section"><h2><a name="BalancerGrowth" id="BalancerGrowth">BalancerGrowth</a> <a name="balancergrowth" id="balancergrowth">Directive</a></h2>
476 <table class="directive">
477 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of additional Balancers that can be added Post-configuration</td></tr>
478 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>BalancerGrowth <var>#</var></code></td></tr>
479 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>BalancerGrowth 5</code></td></tr>
480 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
481 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
482 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
483 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>BalancerGrowth is only available in Apache HTTP Server 2.3.13
486 <p>This directive allows for growth potential in the number of
487 Balancers available for a virtualhost in addition to the
488 number pre-configured. It only takes effect if there is at
489 least 1 pre-configured Balancer.</p>
492 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
493 <div class="directive-section"><h2><a name="BalancerInherit" id="BalancerInherit">BalancerInherit</a> <a name="balancerinherit" id="balancerinherit">Directive</a></h2>
494 <table class="directive">
495 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Inherit proxy Balancers/Workers defined from the main server</td></tr>
496 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>BalancerInherit On|Off</code></td></tr>
497 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>BalancerInherit On</code></td></tr>
498 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
499 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
500 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
501 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>BalancerInherit is only available in Apache HTTP Server 2.4.4 and later.
504 <p>This directive will cause the current server/vhost to "inherit"
505 Balancers and Workers defined in the main server. This can cause issues and
506 inconsistent behavior if using the Balancer Manager for dynamic changes
507 and so should be disabled if using that feature.</p>
508 <p>The setting in the global server defines the default for all vhosts.</p>
509 <p>Disabling <code class="directive"><a href="#proxypassinherit">ProxyPassInherit</a></code> also disables BalancerInherit.</p>
512 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
513 <div class="directive-section"><h2><a name="BalancerMember" id="BalancerMember">BalancerMember</a> <a name="balancermember" id="balancermember">Directive</a></h2>
514 <table class="directive">
515 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Add a member to a load balancing group</td></tr>
516 <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>
517 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
518 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
519 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
521 <p>This directive adds a member to a load balancing group. It could be used
522 within a <code><Proxy <var>balancer://</var>...></code> container
523 directive, and can take any of the key value pair parameters available to
524 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directives.</p>
525 <p>One additional parameter is available only to <code class="directive"><a href="#balancermember">BalancerMember</a></code> directives:
526 <var>loadfactor</var>. This is the member load factor - a number between 1
527 (default) and 100, which defines the weighted load to be applied to the
528 member in question.</p>
529 <p>The balancerurl is only needed when not in <code><Proxy <var>balancer://</var>...></code>
530 container directive. It corresponds to the url of a balancer defined in
531 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.</p>
532 <p>The path component of the balancer URL in any
533 <code><Proxy <var>balancer://</var>...></code> container directive
535 <p>Trailing slashes should typically be removed from the URL of a
536 <code>BalancerMember</code>.</p>
539 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
540 <div class="directive-section"><h2><a name="BalancerPersist" id="BalancerPersist">BalancerPersist</a> <a name="balancerpersist" id="balancerpersist">Directive</a></h2>
541 <table class="directive">
542 <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>
543 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>BalancerPersist On|Off</code></td></tr>
544 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>BalancerPersist Off</code></td></tr>
545 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
546 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
547 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
548 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>BalancerPersist is only available in Apache HTTP Server 2.5.0
551 <p>This directive will cause the shared memory storage associated
552 with the balancers and balancer members to be persisted across
553 restarts. This allows these local changes to not be lost during the
554 normal restart/graceful state transitions.</p>
557 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
558 <div class="directive-section"><h2><a name="NoProxy" id="NoProxy">NoProxy</a> <a name="noproxy" id="noproxy">Directive</a></h2>
559 <table class="directive">
560 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Hosts, domains, or networks that will be connected to
562 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>NoProxy <var>host</var> [<var>host</var>] ...</code></td></tr>
563 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
564 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
565 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
567 <p>This directive is only useful for Apache httpd proxy servers within
568 intranets. The <code class="directive">NoProxy</code> directive specifies a
569 list of subnets, IP addresses, hosts and/or domains, separated by
570 spaces. A request to a host which matches one or more of these is
571 always served directly, without forwarding to the configured
572 <code class="directive"><a href="#proxyremote">ProxyRemote</a></code> proxy server(s).</p>
574 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">
575 ProxyRemote * http://firewall.example.com:81
576 NoProxy .example.com 192.168.112.0/21
580 <p>The <var>host</var> arguments to the <code class="directive">NoProxy</code>
581 directive are one of the following type list:</p>
585 <dt><var><a name="domain" id="domain">Domain</a></var></dt>
587 <p>A <dfn>Domain</dfn> is a partially qualified DNS domain name, preceded
588 by a period. It represents a list of hosts which logically belong to the
589 same DNS domain or zone (<em>i.e.</em>, the suffixes of the hostnames are
590 all ending in <var>Domain</var>).</p>
592 <div class="example"><h3>Examples</h3><p><code>
596 <p>To distinguish <var>Domain</var>s from <var><a href="#hostname">Hostname</a></var>s (both syntactically and semantically; a DNS domain can
597 have a DNS A record, too!), <var>Domain</var>s are always written with a
600 <div class="note"><h3>Note</h3>
601 <p>Domain name comparisons are done without regard to the case, and
602 <var>Domain</var>s are always assumed to be anchored in the root of the
603 DNS tree, therefore two domains <code>.ExAmple.com</code> and
604 <code>.example.com.</code> (note the trailing period) are considered
605 equal. Since a domain comparison does not involve a DNS lookup, it is much
606 more efficient than subnet comparison.</p>
610 <dt><var><a name="subnet" id="subnet">SubNet</a></var></dt>
612 <p>A <dfn>SubNet</dfn> is a partially qualified internet address in
613 numeric (dotted quad) form, optionally followed by a slash and the netmask,
614 specified as the number of significant bits in the <var>SubNet</var>. It is
615 used to represent a subnet of hosts which can be reached over a common
616 network interface. In the absence of the explicit net mask it is assumed
617 that omitted (or zero valued) trailing digits specify the mask. (In this
618 case, the netmask can only be multiples of 8 bits wide.) Examples:</p>
621 <dt><code>192.168</code> or <code>192.168.0.0</code></dt>
622 <dd>the subnet 192.168.0.0 with an implied netmask of 16 valid bits
623 (sometimes used in the netmask form <code>255.255.0.0</code>)</dd>
624 <dt><code>192.168.112.0/21</code></dt>
625 <dd>the subnet <code>192.168.112.0/21</code> with a netmask of 21
626 valid bits (also used in the form <code>255.255.248.0</code>)</dd>
629 <p>As a degenerate case, a <em>SubNet</em> with 32 valid bits is the
630 equivalent to an <var><a href="#ipaddr">IPAddr</a></var>, while a <var>SubNet</var> with zero
631 valid bits (<em>e.g.</em>, 0.0.0.0/0) is the same as the constant
632 <var>_Default_</var>, matching any IP address.</p></dd>
635 <dt><var><a name="ipaddr" id="ipaddr">IPAddr</a></var></dt>
637 <p>A <dfn>IPAddr</dfn> represents a fully qualified internet address in
638 numeric (dotted quad) form. Usually, this address represents a host, but
639 there need not necessarily be a DNS domain name connected with the
641 <div class="example"><h3>Example</h3><p><code>
645 <div class="note"><h3>Note</h3>
646 <p>An <var>IPAddr</var> does not need to be resolved by the DNS system, so
647 it can result in more effective apache performance.</p>
651 <dt><var><a name="hostname" id="hostname">Hostname</a></var></dt>
653 <p>A <dfn>Hostname</dfn> is a fully qualified DNS domain name which can
654 be resolved to one or more <var><a href="#ipaddr">IPAddrs</a></var> via the
655 DNS domain name service. It represents a logical host (in contrast to
656 <var><a href="#domain">Domain</a></var>s, see above) and must be resolvable
657 to at least one <var><a href="#ipaddr">IPAddr</a></var> (or often to a list
658 of hosts with different <var><a href="#ipaddr">IPAddr</a></var>s).</p>
660 <div class="example"><h3>Examples</h3><p><code>
661 prep.ai.example.edu<br />
665 <div class="note"><h3>Note</h3>
666 <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
667 DNS lookup can be avoided. Name resolution in Apache httpd can take a remarkable
668 deal of time when the connection to the name server uses a slow PPP
670 <p><var>Hostname</var> comparisons are done without regard to the case,
671 and <var>Hostname</var>s are always assumed to be anchored in the root
672 of the DNS tree, therefore two hosts <code>WWW.ExAmple.com</code>
673 and <code>www.example.com.</code> (note the trailing period) are
674 considered equal.</p>
680 <li><a href="../dns-caveats.html">DNS Issues</a></li>
683 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
684 <div class="directive-section"><h2><a name="Proxy" id="Proxy"><Proxy></a> <a name="proxy" id="proxy">Directive</a></h2>
685 <table class="directive">
686 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Container for directives applied to proxied resources</td></tr>
687 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Proxy <var>wildcard-url</var>> ...</Proxy></code></td></tr>
688 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
689 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
690 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
692 <p>Directives placed in <code class="directive"><Proxy></code>
693 sections apply only to matching proxied content. Shell-style wildcards are
696 <p>For example, the following will allow only hosts in
697 <code>yournetwork.example.com</code> to access content via your proxy
700 <pre class="prettyprint lang-config">
702 Require host yournetwork.example.com
707 <p>The following example will process all files in the <code>foo</code>
708 directory of <code>example.com</code> through the <code>INCLUDES</code>
709 filter when they are sent through the proxy server:</p>
711 <pre class="prettyprint lang-config">
712 <Proxy http://example.com/foo/*>
713 SetOutputFilter INCLUDES
721 <li><code class="directive"><a href="#proxymatch"><ProxyMatch></a></code></li>
724 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
725 <div class="directive-section"><h2><a name="ProxyAddHeaders" id="ProxyAddHeaders">ProxyAddHeaders</a> <a name="proxyaddheaders" id="proxyaddheaders">Directive</a></h2>
726 <table class="directive">
727 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Add proxy information in X-Forwarded-* headers</td></tr>
728 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyAddHeaders Off|On</code></td></tr>
729 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyAddHeaders On</code></td></tr>
730 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
731 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
732 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
733 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in version 2.3.10 and later</td></tr>
735 <p>This directive determines whether or not proxy related information should be passed to the
736 backend server through X-Forwarded-For, X-Forwarded-Host and X-Forwarded-Server HTTP headers.</p>
737 <div class="note"><h3>Effectiveness</h3>
738 <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>
742 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
743 <div class="directive-section"><h2><a name="ProxyBadHeader" id="ProxyBadHeader">ProxyBadHeader</a> <a name="proxybadheader" id="proxybadheader">Directive</a></h2>
744 <table class="directive">
745 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines how to handle bad header lines in a
747 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyBadHeader IsError|Ignore|StartBody</code></td></tr>
748 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyBadHeader IsError</code></td></tr>
749 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
750 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
751 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
753 <p>The <code class="directive">ProxyBadHeader</code> directive determines the
754 behaviour of <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> if it receives syntactically invalid
755 response header lines (<em>i.e.</em> containing no colon) from the origin
756 server. The following arguments are possible:</p>
759 <dt><code>IsError</code></dt>
760 <dd>Abort the request and end up with a 502 (Bad Gateway) response. This is
761 the default behaviour.</dd>
763 <dt><code>Ignore</code></dt>
764 <dd>Treat bad header lines as if they weren't sent.</dd>
766 <dt><code>StartBody</code></dt>
767 <dd>When receiving the first bad header line, finish reading the headers and
768 treat the remainder as body. This helps to work around buggy backend servers
769 which forget to insert an empty line between the headers and the body.</dd>
773 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
774 <div class="directive-section"><h2><a name="ProxyBlock" id="ProxyBlock">ProxyBlock</a> <a name="proxyblock" id="proxyblock">Directive</a></h2>
775 <table class="directive">
776 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Disallow proxy requests to certain hosts</td></tr>
777 <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>
778 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
779 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
780 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
782 <p>The <code class="directive">ProxyBlock</code> directive can be used to
783 block FTP or HTTP access to certain hosts via the proxy, based on
784 a full or partial hostname match, or, if applicable, an IP address
787 <p>Each of the arguments to the <code class="directive">ProxyBlock</code>
788 directive can be either <code>*</code> or a alphanumeric string.
789 At startup, the module will attempt to resolve every alphanumeric
790 string from a DNS name to a set of IP addresses, but any DNS errors
793 <p>If an asterisk "<code>*</code>" argument is specified,
794 <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> will deny access to all FTP or HTTP
797 <p>Otherwise, for any request for an HTTP or FTP resource via the
798 proxy, <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> will check the hostname of the
799 request URI against each specified string. If a partial string
800 match is found, access is denied. If no matches against hostnames
801 are found, and a remote (forward) proxy is configured using
802 <code class="directive">ProxyRemote</code> or
803 <code class="directive">ProxyRemoteMatch</code>, access is allowed. If no
804 remote (forward) proxy is configured, the IP address of the
805 hostname from the URI is compared against all resolved IP
806 addresses determined at startup. Access is denied if any match is
809 <p>Note that the DNS lookups may slow down the startup time of the
812 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">
813 ProxyBlock news.example.com auctions.example.com friends.example.com
817 <p>Note that <code>example</code> would also be sufficient to match any
820 <p>Hosts would also be matched if referenced by IP address.</p>
822 <p>Note also that</p>
824 <pre class="prettyprint lang-config">
829 <p>blocks connections to all sites.</p>
832 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
833 <div class="directive-section"><h2><a name="ProxyDomain" id="ProxyDomain">ProxyDomain</a> <a name="proxydomain" id="proxydomain">Directive</a></h2>
834 <table class="directive">
835 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Default domain name for proxied requests</td></tr>
836 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyDomain <var>Domain</var></code></td></tr>
837 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
838 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
839 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
841 <p>This directive is only useful for Apache httpd proxy servers within
842 intranets. The <code class="directive">ProxyDomain</code> directive specifies
843 the default domain which the apache proxy server will belong to. If a
844 request to a host without a domain name is encountered, a redirection
845 response to the same host with the configured <var>Domain</var> appended
846 will be generated.</p>
848 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">
849 ProxyRemote * http://firewall.example.com:81<br />
850 NoProxy .example.com 192.168.112.0/21<br />
851 ProxyDomain .example.com
856 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
857 <div class="directive-section"><h2><a name="ProxyErrorOverride" id="ProxyErrorOverride">ProxyErrorOverride</a> <a name="proxyerroroverride" id="proxyerroroverride">Directive</a></h2>
858 <table class="directive">
859 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Override error pages for proxied content</td></tr>
860 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyErrorOverride On|Off</code></td></tr>
861 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyErrorOverride Off</code></td></tr>
862 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
863 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
864 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
866 <p>This directive is useful for reverse-proxy setups, where you want to
867 have a common look and feel on the error pages seen by the end user.
868 This also allows for included files (via
869 <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>'s SSI) to get
870 the error code and act accordingly (default behavior would display
871 the error page of the proxied server, turning this on shows the SSI
874 <p>This directive does not affect the processing of informational (1xx),
875 normal success (2xx), or redirect (3xx) responses.</p>
878 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
879 <div class="directive-section"><h2><a name="ProxyIOBufferSize" id="ProxyIOBufferSize">ProxyIOBufferSize</a> <a name="proxyiobuffersize" id="proxyiobuffersize">Directive</a></h2>
880 <table class="directive">
881 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine size of internal data throughput buffer</td></tr>
882 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyIOBufferSize <var>bytes</var></code></td></tr>
883 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyIOBufferSize 8192</code></td></tr>
884 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
885 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
886 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
888 <p>The <code class="directive">ProxyIOBufferSize</code> directive adjusts the size
889 of the internal buffer, which is used as a scratchpad for the data between
890 input and output. The size must be at least <code>512</code>.</p>
892 <p>In almost every case there's no reason to change that value.</p>
894 <p>If used with AJP this directive sets the maximum AJP packet size in
895 bytes. Values larger than 65536 are set to 65536. If you change it from
896 the default, you must also change the <code>packetSize</code> attribute of
897 your AJP connector on the Tomcat side! The attribute
898 <code>packetSize</code> is only available in Tomcat <code>5.5.20+</code>
899 and <code>6.0.2+</code></p>
901 <p>Normally it is not necessary to change the maximum packet size.
902 Problems with the default value have been reported when sending
903 certificates or certificate chains.</p>
907 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
908 <div class="directive-section"><h2><a name="ProxyMatch" id="ProxyMatch"><ProxyMatch></a> <a name="proxymatch" id="proxymatch">Directive</a></h2>
909 <table class="directive">
910 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Container for directives applied to regular-expression-matched
911 proxied resources</td></tr>
912 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><ProxyMatch <var>regex</var>> ...</ProxyMatch></code></td></tr>
913 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
914 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
915 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
917 <p>The <code class="directive"><ProxyMatch></code> directive is
918 identical to the <code class="directive"><a href="#proxy"><Proxy></a></code> directive, except it matches URLs
919 using <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expressions</a>.</p>
923 <li><code class="directive"><a href="#proxy"><Proxy></a></code></li>
926 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
927 <div class="directive-section"><h2><a name="ProxyMaxForwards" id="ProxyMaxForwards">ProxyMaxForwards</a> <a name="proxymaxforwards" id="proxymaxforwards">Directive</a></h2>
928 <table class="directive">
929 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximium number of proxies that a request can be forwarded
931 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyMaxForwards <var>number</var></code></td></tr>
932 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyMaxForwards -1</code></td></tr>
933 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
934 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
935 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
937 <p>The <code class="directive">ProxyMaxForwards</code> directive specifies the
938 maximum number of proxies through which a request may pass, if there's no
939 <code>Max-Forwards</code> header supplied with the request. This may
940 be set to prevent infinite proxy loops, or a DoS attack.</p>
942 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">
947 <p>Note that setting <code class="directive">ProxyMaxForwards</code> is a
948 violation of the HTTP/1.1 protocol (RFC2616), which forbids a Proxy
949 setting <code>Max-Forwards</code> if the Client didn't set it.
950 Earlier Apache httpd versions would always set it. A negative
951 <code class="directive">ProxyMaxForwards</code> value, including the
952 default -1, gives you protocol-compliant behaviour, but may
953 leave you open to loops.</p>
956 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
957 <div class="directive-section"><h2><a name="ProxyPass" id="ProxyPass">ProxyPass</a> <a name="proxypass" id="proxypass">Directive</a></h2>
958 <table class="directive">
959 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maps remote servers into the local server URL-space</td></tr>
960 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPass [<var>path</var>] !|<var>url</var> [<var>key=value</var>
961 <var>[key=value</var> ...]] [nocanon] [interpolate] [noquery]</code></td></tr>
962 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
963 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
964 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
966 <p>This directive allows remote servers to be mapped into the
967 space of the local server; the local server does not act as a
968 proxy in the conventional sense, but appears to be a mirror of the
969 remote server. The local server is often called a <dfn>reverse
970 proxy</dfn> or <dfn>gateway</dfn>. The <var>path</var> is the name of
971 a local virtual path; <var>url</var> is a partial URL for the
972 remote server and cannot include a query string.</p>
974 <div class="note"><strong>Note: </strong>This directive cannot be used within a
975 <code><Directory></code> context.</div>
977 <div class="warning">The <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> directive should
978 usually be set <strong>off</strong> when using
979 <code class="directive">ProxyPass</code>.</div>
981 <p>Suppose the local server has address <code>http://example.com/</code>;
984 <pre class="prettyprint lang-config">
985 <Location /mirror/foo/>
986 ProxyPass http://backend.example.com/
991 <p>will cause a local request for
992 <code>http://example.com/mirror/foo/bar</code> to be internally converted
993 into a proxy request to <code>http://backend.example.com/bar</code>.</p>
995 <p>The following alternative syntax is possible, however it can carry a
996 performance penalty when present in very large numbers. The advantage of
997 the below syntax is that it allows for dynamic control via the
998 <a href="mod_proxy_balancer.html#balancer_manager">Balancer Manager</a> interface:</p>
1000 <pre class="prettyprint lang-config">
1001 ProxyPass /mirror/foo/ http://backend.example.com/
1005 <div class="warning">
1006 <p>If the first argument ends with a trailing <strong>/</strong>, the second
1007 argument should also end with a trailing <strong>/</strong> and vice
1008 versa. Otherwise the resulting requests to the backend may miss some
1009 needed slashes and do not deliver the expected results.
1013 <p>The <code>!</code> directive is useful in situations where you don't want
1014 to reverse-proxy a subdirectory, <em>e.g.</em></p>
1016 <pre class="prettyprint lang-config">
1017 <Location /mirror/foo/>
1018 ProxyPass http://backend.example.com/
1020 <Location /mirror/foo/i>
1026 <pre class="prettyprint lang-config">
1027 ProxyPass /mirror/foo/i !
1028 ProxyPass /mirror/foo http://backend.example.com
1032 <p>will proxy all requests to <code>/mirror/foo</code> to
1033 <code>backend.example.com</code> <em>except</em> requests made to
1034 <code>/mirror/foo/i</code>.</p>
1036 <div class="warning"><h3>Ordering ProxyPass Directives</h3>
1037 <p>The configured <code class="directive"><a href="#proxypass">ProxyPass</a></code>
1038 and <code class="directive"><a href="#proxypassmatch">ProxyPassMatch</a></code>
1039 rules are checked in the order of configuration. The first rule that
1040 matches wins. So usually you should sort conflicting
1041 <code class="directive"><a href="#proxypass">ProxyPass</a></code> rules starting with the
1042 longest URLs first. Otherwise later rules for longer URLS will be hidden
1043 by any earlier rule which uses a leading substring of the URL. Note that
1044 there is some relation with worker sharing. In contrast, only one
1045 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive can be placed
1046 in a <code class="directive"><a href="../mod/core.html#location">Location</a></code> block, and the most
1047 specific location will take precedence.</p>
1049 <p>For the same reasons exclusions must come <em>before</em> the
1050 general <code class="directive">ProxyPass</code> directives.</p>
1054 <p>In Apache HTTP Server 2.1 and later, mod_proxy supports pooled
1055 connections to a backend server. Connections created on demand
1056 can be retained in a pool for future use. Limits on the pool size
1057 and other settings can be coded on
1058 the <code class="directive">ProxyPass</code> directive
1059 using <code>key=value</code> parameters, described in the table
1062 <p>By default, mod_proxy will allow and retain the maximum number of
1063 connections that could be used simultaneously by that web server child
1064 process. Use the <code>max</code> parameter to reduce the number from
1065 the default. Use the <code>ttl</code> parameter to set an optional
1066 time to live; connections which have been unused for at least
1067 <code>ttl</code> seconds will be closed. <code>ttl</code> can be used
1068 to avoid using a connection which is subject to closing because of the
1069 backend server's keep-alive timeout.</p>
1071 <p>The pool of connections is maintained per web server child
1072 process, and <code>max</code> and other settings are not coordinated
1073 among all child processes, except when only one child process is allowed
1074 by configuration or MPM design.</p>
1076 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">
1077 ProxyPass /example http://backend.example.com max=20 ttl=120 retry=300
1081 <table class="bordered"><tr><th>BalancerMember parameters</th></tr></table>
1083 <tr><th>Parameter</th>
1085 <th>Description</th></tr>
1088 <td>Minimum number of connection pool entries, unrelated to the
1089 actual number of connections. This only needs to be modified from the
1090 default for special circumstances where heap memory associated with the
1091 backend connections should be preallocated or retained.</td></tr>
1094 <td>Maximum number of connections that will be allowed to the
1095 backend server. The default for this limit is the number of threads
1096 per process in the active MPM. In the Prefork MPM, this is always 1,
1097 while with other MPMs it is controlled by the
1098 <code class="directive">ThreadsPerChild</code> directive.</td></tr>
1101 <td>Retained connection pool entries above this limit are freed
1102 during certain operations if they have been unused for longer than
1103 the time to live, controlled by the <code>ttl</code> parameter. If
1104 the connection pool entry has an associated connection, it will be
1105 closed. This only needs to be modified from the default for special
1106 circumstances where connection pool entries and any associated
1107 connections which have exceeded the time to live need to be freed or
1108 closed more aggressively.</td></tr>
1109 <tr><td>acquire</td>
1111 <td>If set this will be the maximum time to wait for a free
1112 connection in the connection pool, in milliseconds. If there are no free
1113 connections in the pool the Apache httpd will return <code>SERVER_BUSY</code>
1114 status to the client.
1116 <tr><td>connectiontimeout</td>
1118 <td>Connect timeout in seconds.
1119 The number of seconds Apache httpd waits for the creation of a connection to
1120 the backend to complete. By adding a postfix of ms the timeout can be
1121 also set in milliseconds.
1123 <tr><td>disablereuse</td>
1125 <td>This parameter should be used when you want to force mod_proxy
1126 to immediately close a connection to the backend after being used, and
1127 thus, disable its persistent connection and pool for that backend.
1128 This helps in various situations where a firewall between Apache
1130 the backend server (regardless of protocol) tends to silently
1131 drop connections or when backends themselves may be under round-
1132 robin DNS. To disable connection pooling reuse,
1133 set this property value to <code>On</code>.
1135 <tr><td>flushpackets</td>
1137 <td>Determines whether the proxy module will auto-flush the output
1138 brigade after each "chunk" of data. 'off' means that it will flush
1139 only when needed, 'on' means after each chunk is sent and
1140 'auto' means poll/wait for a period of time and flush if
1141 no input has been received for 'flushwait' milliseconds.
1142 Currently this is in effect only for AJP.
1144 <tr><td>flushwait</td>
1146 <td>The time to wait for additional input, in milliseconds, before
1147 flushing the output brigade if 'flushpackets' is 'auto'.
1149 <tr><td>iobuffersize</td>
1151 <td>Adjusts the size of the internal scratchpad IO buffer. This allows you
1152 to override the <code class="directive">ProxyIOBufferSize</code> for a specific worker.
1153 This must be at least 512 or set to 0 for the system default of 8192.
1155 <tr><td>keepalive</td>
1157 <td><p>This parameter should be used when you have a firewall between your
1158 Apache httpd and the backend server, who tend to drop inactive connections.
1159 This flag will tell the Operating System to send <code>KEEP_ALIVE</code>
1160 messages on inactive connections and thus prevent the firewall to drop the connection.
1161 To enable keepalive set this property value to <code>On</code>. </p>
1162 <p>The frequency of initial and subsequent TCP keepalive probes
1163 depends on global OS settings, and may be as high as 2 hours. To be useful,
1164 the frequency configured in the OS must be smaller than the threshold used
1165 by the firewall.</p>
1169 <td>Sets the load balancer cluster set that the worker is a member
1170 of. The load balancer will try all members of a lower numbered
1171 lbset before trying higher numbered ones.
1175 <td>Ping property tells the webserver to "test" the connection to
1176 the backend before forwarding the request. For AJP, it causes
1177 <code class="module"><a href="../mod/mod_proxy_ajp.html">mod_proxy_ajp</a></code>to send a <code>CPING</code>
1178 request on the ajp13 connection (implemented on Tomcat 3.3.2+, 4.1.28+
1179 and 5.0.13+). For HTTP, it causes <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code>
1180 to send a <code>100-Continue</code> to the backend (only valid for
1181 HTTP/1.1 - for non HTTP/1.1 backends, this property has no
1182 effect). In both cases the parameter is the delay in seconds to wait
1184 This feature has been added to avoid problems with hung and
1186 This will increase the network traffic during the normal operation
1187 which could be an issue, but it will lower the
1188 traffic in case some of the cluster nodes are down or busy.
1189 By adding a postfix of ms the delay can be also set in
1192 <tr><td>receivebuffersize</td>
1194 <td>Adjusts the size of the explicit (TCP/IP) network buffer size for
1195 proxied connections. This allows you to override the
1196 <code class="directive">ProxyReceiveBufferSize</code> for a specific worker.
1197 This must be at least 512 or set to 0 for the system default.
1199 <tr><td>redirect</td>
1201 <td>Redirection Route of the worker. This value is usually
1202 set dynamically to enable safe removal of the node from
1203 the cluster. If set all requests without session id will be
1204 redirected to the BalancerMember that has route parameter
1205 equal as this value.
1209 <td>Connection pool worker retry timeout in seconds.
1210 If the connection pool worker to the backend server is in the error state,
1211 Apache httpd will not forward any requests to that server until the timeout
1212 expires. This enables to shut down the backend server for maintenance,
1213 and bring it back online later. A value of 0 means always retry workers
1214 in an error state with no timeout.
1218 <td>Route of the worker when used inside load balancer.
1219 The route is a value appended to session id.
1223 <td>Single letter value defining the initial status of
1226 <tr><td>D: Worker is disabled and will not accept any requests.</td></tr>
1227 <tr><td>S: Worker is administratively stopped.</td></tr>
1228 <tr><td>I: Worker is in ignore-errors mode, and will always be considered available.</td></tr>
1229 <tr><td>H: Worker is in hot-standby mode and will only be used if no other
1230 viable workers are available.</td></tr>
1231 <tr><td>E: Worker is in an error state.</td></tr>
1232 <tr><td>N: Worker is in drain mode, and will only accept existing sticky sessions
1233 destined for itself and ignore all other requests.</td></tr>
1235 can be set (which is the default) by prepending with '+' or
1236 cleared by prepending with '-'.
1237 Thus, a setting of 'S-E' sets this worker to Stopped and
1238 clears the in-error flag.
1240 <tr><td>timeout</td>
1241 <td><code class="directive"><a href="#proxytimeout">ProxyTimeout</a></code></td>
1242 <td>Connection timeout in seconds.
1243 The number of seconds Apache httpd waits for data sent by / to the backend.
1247 <td>Time to live for inactive connections and associated connection
1248 pool entries, in seconds. Once reaching this limit, a
1249 connection will not be used again; it will be closed at some
1255 <p>If the Proxy directive scheme starts with the
1256 <code>balancer://</code> (eg: <code>balancer://cluster</code>,
1257 any path information is ignored) then a virtual worker that does not really
1258 communicate with the backend server will be created. Instead it is responsible
1259 for the management of several "real" workers. In that case the special set of
1260 parameters can be add to this virtual worker. See <code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code>
1261 for more information about how the balancer works.
1263 <table class="bordered"><tr><th>Balancer parameters</th></tr></table>
1265 <tr><th>Parameter</th>
1267 <th>Description</th></tr>
1268 <tr><td>lbmethod</td>
1270 <td>Balancer load-balance method. Select the load-balancing scheduler
1271 method to use. Either <code>byrequests</code>, to perform weighted
1272 request counting, <code>bytraffic</code>, to perform weighted
1273 traffic byte count balancing, or <code>bybusyness</code>, to perform
1274 pending request balancing. Default is <code>byrequests</code>.
1276 <tr><td>maxattempts</td>
1277 <td>One less than the number of workers, or 1 with a single worker.</td>
1278 <td>Maximum number of failover attempts before giving up.
1280 <tr><td>nofailover</td>
1282 <td>If set to <code>On</code> the session will break if the worker is in
1283 error state or disabled. Set this value to On if backend servers do not
1284 support session replication.
1286 <tr><td>stickysession</td>
1288 <td>Balancer sticky session name. The value is usually set to something
1289 like <code>JSESSIONID</code> or <code>PHPSESSIONID</code>,
1290 and it depends on the backend application server that support sessions.
1291 If the backend application server uses different name for cookies
1292 and url encoded id (like servlet containers) use | to to separate them.
1293 The first part is for the cookie the second for the path.
1295 <tr><td>stickysessionsep</td>
1297 <td>Sets the separation symbol in the session cookie. Some backend application servers
1298 do not use the '.' as the symbol. For example the Oracle Weblogic server uses
1299 '!'. The correct symbol can be set using this option. The setting of 'Off'
1300 signifies that no symbol is used.
1302 <tr><td>scolonpathdelim</td>
1304 <td>If set to <code>On</code> the semi-colon character ';' will be
1305 used as an additional sticky session path deliminator/separator. This
1306 is mainly used to emulate mod_jk's behavior when dealing with paths such
1307 as <code>JSESSIONID=6736bcf34;foo=aabfa</code>
1309 <tr><td>timeout</td>
1311 <td>Balancer timeout in seconds. If set this will be the maximum time
1312 to wait for a free worker. Default is not to wait.
1314 <tr><td>failonstatus</td>
1316 <td>A single or comma-separated list of HTTP status codes. If set this will
1317 force the worker into error state when the backend returns any status code
1318 in the list. Worker recovery behaves the same as other worker errors.
1320 <tr><td>failontimeout</td>
1322 <td>If set, an IO read timeout after a request is sent to the backend will
1323 force the worker into error state. Worker recovery behaves the same as other
1327 <td><auto></td>
1328 <td>The protective nonce used in the <code>balancer-manager</code> application page.
1329 The default is to use an automatically determined UUID-based
1330 nonce, to provide for further protection for the page. If set,
1331 then the nonce is set to that value. A setting of <code>None</code>
1332 disables all nonce checking.
1333 <div class="note"><h3>Note</h3>
1334 <p>In addition to the nonce, the <code>balancer-manager</code> page
1335 should be protected via an ACL.</p>
1340 <td>Number of additional BalancerMembers to allow to be added
1341 to this balancer in addition to those defined at configuration.
1343 <tr><td>forcerecovery</td>
1345 <td>Force the immediate recovery of all workers without considering the
1346 retry parameter of the workers if all workers of a balancer are
1347 in error state. There might be cases where an already overloaded backend
1348 can get into deeper trouble if the recovery of all workers is enforced
1349 without considering the retry parameter of each worker. In this case
1350 set to <code>Off</code>.
1354 <p>A sample balancer setup</p>
1355 <pre class="prettyprint lang-config">
1356 ProxyPass /special-area http://special.example.com smax=5 max=10
1357 ProxyPass / balancer://mycluster/ stickysession=JSESSIONID|jsessionid nofailover=On
1358 <Proxy balancer://mycluster>
1359 BalancerMember ajp://1.2.3.4:8009
1360 BalancerMember ajp://1.2.3.5:8009 loadfactor=20
1361 # Less powerful server, don't send as many requests there,
1362 BalancerMember ajp://1.2.3.6:8009 loadfactor=5
1367 <p>Setting up a hot-standby, that will only be used if no other
1368 members are available</p>
1369 <pre class="prettyprint lang-config">
1370 ProxyPass / balancer://hotcluster/
1371 <Proxy balancer://hotcluster>
1372 BalancerMember ajp://1.2.3.4:8009 loadfactor=1
1373 BalancerMember ajp://1.2.3.5:8009 loadfactor=2
1374 # The server below is on hot standby
1375 BalancerMember ajp://1.2.3.6:8009 status=+H
1376 ProxySet lbmethod=bytraffic
1381 <p>Normally, mod_proxy will canonicalise ProxyPassed URLs.
1382 But this may be incompatible with some backends, particularly those
1383 that make use of <var>PATH_INFO</var>. The optional <var>nocanon</var>
1384 keyword suppresses this, and passes the URL path "raw" to the
1385 backend. Note that may affect the security of your backend, as it
1386 removes the normal limited protection against URL-based attacks
1387 provided by the proxy.</p>
1389 <p>The optional <var>interpolate</var> keyword (available in
1390 httpd 2.2.9 and later), in combination with
1391 <code class="directive">ProxyPassInterpolateEnv</code> causes the ProxyPass
1392 to interpolate environment variables, using the syntax
1393 <var>${VARNAME}</var>. Note that many of the standard CGI-derived
1394 environment variables will not exist when this interpolation happens,
1395 so you may still have to resort to <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>
1396 for complex rules.</p>
1398 <p>Normally, mod_proxy will include the query string when
1399 generating the <var>SCRIPT_FILENAME</var> environment variable.
1400 The optional <var>noquery</var> keyword (available in
1401 httpd 2.4.1 and later) prevents this.</p>
1403 <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
1404 directory is obtained from the <code class="directive"><a href="../mod/core.html#location"><Location></a></code>. The same will occur inside a
1405 <code class="directive"><a href="../mod/core.html#locationmatch"><LocationMatch></a></code> section,
1406 however ProxyPass does not interpret the regexp as such, so it is necessary
1407 to use <code class="directive">ProxyPassMatch</code> in this situation instead.</p>
1409 <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>
1411 <p>If you require a more flexible reverse-proxy configuration, see the
1412 <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> directive with the
1413 <code>[P]</code> flag.</p>
1417 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1418 <div class="directive-section"><h2><a name="ProxyPassInherit" id="ProxyPassInherit">ProxyPassInherit</a> <a name="proxypassinherit" id="proxypassinherit">Directive</a></h2>
1419 <table class="directive">
1420 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Inherit ProxyPass directives defined from the main server</td></tr>
1421 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassInherit On|Off</code></td></tr>
1422 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyPassInherit On</code></td></tr>
1423 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1424 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1425 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1426 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>ProxyPassInherit is only available in Apache HTTP Server 2.5.0 and later.
1427 and later.</td></tr>
1429 <p>This directive will cause the current server/vhost to "inherit"
1430 <code class="directive"><a href="#proxypass">ProxyPass</a></code>
1431 directives defined in the main server. This can cause issues and
1432 inconsistent behavior if using the Balancer Manager for dynamic changes
1433 and so should be disabled if using that feature.</p>
1434 <p>The setting in the global server defines the default for all vhosts.</p>
1435 <p>Disabling ProxyPassInherit also disables <code class="directive"><a href="#balancerinherit">BalancerInherit</a></code>.</p>
1438 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1439 <div class="directive-section"><h2><a name="ProxyPassInterpolateEnv" id="ProxyPassInterpolateEnv">ProxyPassInterpolateEnv</a> <a name="proxypassinterpolateenv" id="proxypassinterpolateenv">Directive</a></h2>
1440 <table class="directive">
1441 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enable Environment Variable interpolation in Reverse Proxy configurations</td></tr>
1442 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassInterpolateEnv On|Off</code></td></tr>
1443 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyPassInterpolateEnv Off</code></td></tr>
1444 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1445 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1446 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1448 <p>This directive, together with the <var>interpolate</var> argument to
1449 <code class="directive">ProxyPass</code>, <code class="directive">ProxyPassReverse</code>,
1450 <code class="directive">ProxyPassReverseCookieDomain</code> and
1451 <code class="directive">ProxyPassReverseCookiePath</code>
1452 enables reverse proxies to be dynamically
1453 configured using environment variables, which may be set by
1454 another module such as <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>.
1455 It affects the <code class="directive">ProxyPass</code>,
1456 <code class="directive">ProxyPassReverse</code>,
1457 <code class="directive">ProxyPassReverseCookieDomain</code>, and
1458 <code class="directive">ProxyPassReverseCookiePath</code> directives,
1459 and causes them to substitute the value of an environment
1460 variable <code>varname</code> for the string <code>${varname}</code>
1461 in configuration directives (if the <var>interpolate</var> option is set).</p>
1462 <p>Keep this turned off (for server performance) unless you need it!</p>
1465 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1466 <div class="directive-section"><h2><a name="ProxyPassMatch" id="ProxyPassMatch">ProxyPassMatch</a> <a name="proxypassmatch" id="proxypassmatch">Directive</a></h2>
1467 <table class="directive">
1468 <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>
1469 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassMatch [<var>regex</var>] !|<var>url</var> [<var>key=value</var>
1470 <var>[key=value</var> ...]]</code></td></tr>
1471 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1472 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1473 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1475 <p>This directive is equivalent to <code class="directive"><a href="#proxypass">ProxyPass</a></code>,
1476 but makes use of regular expressions, instead of simple prefix matching. The
1477 supplied regular expression is matched against the <var>url</var>, and if it
1478 matches, the server will substitute any parenthesized matches into the given
1479 string and use it as a new <var>url</var>.</p>
1481 <div class="note"><strong>Note: </strong>This directive cannot be used within a
1482 <code><Directory></code> context.</div>
1484 <p>Suppose the local server has address <code>http://example.com/</code>;
1487 <pre class="prettyprint lang-config">
1488 ProxyPassMatch ^(/.*\.gif)$ http://backend.example.com$1
1492 <p>will cause a local request for
1493 <code>http://example.com/foo/bar.gif</code> to be internally converted
1494 into a proxy request to <code>http://backend.example.com/foo/bar.gif</code>.</p>
1495 <div class="note"><h3>Note</h3>
1496 <p>The URL argument must be parsable as a URL <em>before</em> regexp
1497 substitutions (as well as after). This limits the matches you can use.
1498 For instance, if we had used</p>
1499 <pre class="prettyprint lang-config">
1500 ProxyPassMatch ^(/.*\.gif)$ http://backend.example.com:8000$1
1503 <p>in our previous example, it would fail with a syntax error
1504 at server startup. This is a bug (PR 46665 in the ASF bugzilla),
1505 and the workaround is to reformulate the match:</p>
1506 <pre class="prettyprint lang-config">
1507 ProxyPassMatch ^/(.*\.gif)$ http://backend.example.com:8000/$1
1511 <p>The <code>!</code> directive is useful in situations where you don't want
1512 to reverse-proxy a subdirectory.</p>
1514 <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
1515 regexp is obtained from the <code class="directive"><a href="../mod/core.html#locationmatch"><LocationMatch></a></code>.</p>
1517 <p>If you require a more flexible reverse-proxy configuration, see the
1518 <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> directive with the
1519 <code>[P]</code> flag.</p>
1521 <div class="warning">
1522 <h3>Security Warning</h3>
1523 <p>Take care when constructing the target URL of the rule, considering
1524 the security impact from allowing the client influence over the set of
1525 URLs to which your server will act as a proxy. Ensure that the scheme
1526 and hostname part of the URL is either fixed, or does not allow the
1527 client undue influence.</p>
1531 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1532 <div class="directive-section"><h2><a name="ProxyPassReverse" id="ProxyPassReverse">ProxyPassReverse</a> <a name="proxypassreverse" id="proxypassreverse">Directive</a></h2>
1533 <table class="directive">
1534 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Adjusts the URL in HTTP response headers sent from a reverse
1535 proxied server</td></tr>
1536 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassReverse [<var>path</var>] <var>url</var>
1537 [<var>interpolate</var>]</code></td></tr>
1538 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1539 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1540 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1542 <p>This directive lets Apache httpd adjust the URL in the <code>Location</code>,
1543 <code>Content-Location</code> and <code>URI</code> headers on HTTP
1544 redirect responses. This is essential when Apache httpd is used as a
1545 reverse proxy (or gateway) to avoid by-passing the reverse proxy
1546 because of HTTP redirects on the backend servers which stay behind
1547 the reverse proxy.</p>
1549 <p>Only the HTTP response headers specifically mentioned above
1550 will be rewritten. Apache httpd will not rewrite other response
1551 headers, nor will it by default rewrite URL references inside HTML pages.
1552 This means that if the proxied content contains absolute URL
1553 references, they will by-pass the proxy. To rewrite HTML content to
1554 match the proxy, you must load and enable <code class="module"><a href="../mod/mod_proxy_html.html">mod_proxy_html</a></code>.
1557 <p><var>path</var> is the name of a local virtual path. <var>url</var> is a
1558 partial URL for the remote server - the same way they are used for the
1559 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.</p>
1561 <p>For example, suppose the local server has address
1562 <code>http://example.com/</code>; then</p>
1564 <pre class="prettyprint lang-config">
1565 ProxyPass /mirror/foo/ http://backend.example.com/
1566 ProxyPassReverse /mirror/foo/ http://backend.example.com/
1567 ProxyPassReverseCookieDomain backend.example.com public.example.com
1568 ProxyPassReverseCookiePath / /mirror/foo/
1572 <p>will not only cause a local request for the
1573 <code>http://example.com/mirror/foo/bar</code> to be internally converted
1574 into a proxy request to <code>http://backend.example.com/bar</code>
1575 (the functionality <code>ProxyPass</code> provides here). It also takes care
1576 of redirects the server <code>backend.example.com</code> sends: when
1577 <code>http://backend.example.com/bar</code> is redirected by him to
1578 <code>http://backend.example.com/quux</code> Apache httpd adjusts this to
1579 <code>http://example.com/mirror/foo/quux</code> before forwarding the HTTP
1580 redirect response to the client. Note that the hostname used for
1581 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>
1583 <p>Note that this <code class="directive">ProxyPassReverse</code> directive can
1584 also be used in conjunction with the proxy pass-through feature
1585 (<code>RewriteRule ... [P]</code>) from <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>
1586 because it doesn't depend on a corresponding <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.</p>
1588 <p>The optional <var>interpolate</var> keyword (available in
1589 httpd 2.2.9 and later), used together with
1590 <code class="directive">ProxyPassInterpolateEnv</code>, enables interpolation
1591 of environment variables specified using the format <var>${VARNAME}</var>.
1594 <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
1595 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
1596 intended, as ProxyPassReverse will interpret the regexp literally as a
1597 path; if needed in this situation, specify the ProxyPassReverse outside
1598 the section, or in a separate <code class="directive"><a href="../mod/core.html#location"><Location></a></code> section.</p>
1600 <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>
1603 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1604 <div class="directive-section"><h2><a name="ProxyPassReverseCookieDomain" id="ProxyPassReverseCookieDomain">ProxyPassReverseCookieDomain</a> <a name="proxypassreversecookiedomain" id="proxypassreversecookiedomain">Directive</a></h2>
1605 <table class="directive">
1606 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Adjusts the Domain string in Set-Cookie headers from a reverse-
1607 proxied server</td></tr>
1608 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassReverseCookieDomain <var>internal-domain</var>
1609 <var>public-domain</var> [<var>interpolate</var>]</code></td></tr>
1610 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1611 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1612 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1614 <p>Usage is basically similar to
1615 <code class="directive"><a href="#proxypassreverse">ProxyPassReverse</a></code>, but instead of
1616 rewriting headers that are a URL, this rewrites the <code>domain</code>
1617 string in <code>Set-Cookie</code> headers.</p>
1620 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1621 <div class="directive-section"><h2><a name="ProxyPassReverseCookiePath" id="ProxyPassReverseCookiePath">ProxyPassReverseCookiePath</a> <a name="proxypassreversecookiepath" id="proxypassreversecookiepath">Directive</a></h2>
1622 <table class="directive">
1623 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Adjusts the Path string in Set-Cookie headers from a reverse-
1624 proxied server</td></tr>
1625 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassReverseCookiePath <var>internal-path</var>
1626 <var>public-path</var> [<var>interpolate</var>]</code></td></tr>
1627 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1628 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1629 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1632 Useful in conjunction with
1633 <code class="directive"><a href="#proxypassreverse">ProxyPassReverse</a></code>
1634 in situations where backend URL paths are mapped to public paths on the
1635 reverse proxy. This directive rewrites the <code>path</code> string in
1636 <code>Set-Cookie</code> headers. If the beginning of the cookie path matches
1637 <var>internal-path</var>, the cookie path will be replaced with
1638 <var>public-path</var>.
1640 In the example given with
1641 <code class="directive"><a href="#proxypassreverse">ProxyPassReverse</a></code>, the directive:
1643 <pre class="prettyprint lang-config">
1644 ProxyPassReverseCookiePath / /mirror/foo/
1648 will rewrite a cookie with backend path <code>/</code> (or
1649 <code>/example</code> or, in fact, anything) to <code>/mirror/foo/</code>.
1653 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1654 <div class="directive-section"><h2><a name="ProxyPreserveHost" id="ProxyPreserveHost">ProxyPreserveHost</a> <a name="proxypreservehost" id="proxypreservehost">Directive</a></h2>
1655 <table class="directive">
1656 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Use incoming Host HTTP request header for proxy
1658 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPreserveHost On|Off</code></td></tr>
1659 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyPreserveHost Off</code></td></tr>
1660 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1661 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1662 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1663 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Usable in directory
1664 context in 2.3.3 and later.</td></tr>
1666 <p>When enabled, this option will pass the Host: line from the incoming
1667 request to the proxied host, instead of the hostname specified in the
1668 <code class="directive">ProxyPass</code> line.</p>
1670 <p>This option should normally be turned <code>Off</code>. It is mostly
1671 useful in special configurations like proxied mass name-based virtual
1672 hosting, where the original Host header needs to be evaluated by the
1676 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1677 <div class="directive-section"><h2><a name="ProxyReceiveBufferSize" id="ProxyReceiveBufferSize">ProxyReceiveBufferSize</a> <a name="proxyreceivebuffersize" id="proxyreceivebuffersize">Directive</a></h2>
1678 <table class="directive">
1679 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Network buffer size for proxied HTTP and FTP
1680 connections</td></tr>
1681 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyReceiveBufferSize <var>bytes</var></code></td></tr>
1682 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyReceiveBufferSize 0</code></td></tr>
1683 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1684 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1685 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1687 <p>The <code class="directive">ProxyReceiveBufferSize</code> directive specifies an
1688 explicit (TCP/IP) network buffer size for proxied HTTP and FTP connections,
1689 for increased throughput. It has to be greater than <code>512</code> or set
1690 to <code>0</code> to indicate that the system's default buffer size should
1693 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">
1694 ProxyReceiveBufferSize 2048
1699 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1700 <div class="directive-section"><h2><a name="ProxyRemote" id="ProxyRemote">ProxyRemote</a> <a name="proxyremote" id="proxyremote">Directive</a></h2>
1701 <table class="directive">
1702 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Remote proxy used to handle certain requests</td></tr>
1703 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyRemote <var>match</var> <var>remote-server</var></code></td></tr>
1704 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1705 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1706 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1708 <p>This defines remote proxies to this proxy. <var>match</var> is either the
1709 name of a URL-scheme that the remote server supports, or a partial URL
1710 for which the remote server should be used, or <code>*</code> to indicate
1711 the server should be contacted for all requests. <var>remote-server</var> is
1712 a partial URL for the remote server. Syntax:</p>
1714 <div class="example"><p><code>
1715 <dfn>remote-server</dfn> =
1716 <var>scheme</var>://<var>hostname</var>[:<var>port</var>]
1719 <p><var>scheme</var> is effectively the protocol that should be used to
1720 communicate with the remote server; only <code>http</code> and <code>https</code>
1721 are supported by this module. When using <code>https</code>, the requests
1722 are forwarded through the remote proxy using the HTTP CONNECT method.</p>
1724 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">
1725 ProxyRemote http://goodguys.example.com/ http://mirrorguys.example.com:8000
1726 ProxyRemote * http://cleverproxy.localdomain
1727 ProxyRemote ftp http://ftpproxy.mydomain:8080
1731 <p>In the last example, the proxy will forward FTP requests, encapsulated
1732 as yet another HTTP proxy request, to another proxy which can handle
1735 <p>This option also supports reverse proxy configuration - a backend
1736 webserver can be embedded within a virtualhost URL space even if that
1737 server is hidden by another forward proxy.</p>
1740 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1741 <div class="directive-section"><h2><a name="ProxyRemoteMatch" id="ProxyRemoteMatch">ProxyRemoteMatch</a> <a name="proxyremotematch" id="proxyremotematch">Directive</a></h2>
1742 <table class="directive">
1743 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Remote proxy used to handle requests matched by regular
1744 expressions</td></tr>
1745 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyRemoteMatch <var>regex</var> <var>remote-server</var></code></td></tr>
1746 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1747 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1748 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1750 <p>The <code class="directive">ProxyRemoteMatch</code> is identical to the
1751 <code class="directive"><a href="#proxyremote">ProxyRemote</a></code> directive, except the
1752 first argument is a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>
1753 match against the requested URL.</p>
1756 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1757 <div class="directive-section"><h2><a name="ProxyRequests" id="ProxyRequests">ProxyRequests</a> <a name="proxyrequests" id="proxyrequests">Directive</a></h2>
1758 <table class="directive">
1759 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables forward (standard) proxy requests</td></tr>
1760 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyRequests On|Off</code></td></tr>
1761 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyRequests Off</code></td></tr>
1762 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1763 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1764 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1766 <p>This allows or prevents Apache httpd from functioning as a forward proxy
1767 server. (Setting ProxyRequests to <code>Off</code> does not disable use of
1768 the <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.)</p>
1770 <p>In a typical reverse proxy or gateway configuration, this
1771 option should be set to
1772 <code>Off</code>.</p>
1774 <p>In order to get the functionality of proxying HTTP or FTP sites, you
1775 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>
1776 (or both) present in the server.</p>
1778 <p>In order to get the functionality of (forward) proxying HTTPS sites, you
1779 need <code class="module"><a href="../mod/mod_proxy_connect.html">mod_proxy_connect</a></code> enabled in the server.</p>
1781 <div class="warning"><h3>Warning</h3>
1782 <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
1783 both to your network and to the Internet at large.</p>
1788 <li><a href="#forwardreverse">Forward and Reverse Proxies/Gateways</a></li>
1791 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1792 <div class="directive-section"><h2><a name="ProxySet" id="ProxySet">ProxySet</a> <a name="proxyset" id="proxyset">Directive</a></h2>
1793 <table class="directive">
1794 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Set various Proxy balancer or member parameters</td></tr>
1795 <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>
1796 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
1797 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1798 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1800 <p>This directive is used as an alternate method of setting any of the
1801 parameters available to Proxy balancers and workers normally done via the
1802 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive. If used
1803 within a <code><Proxy <var>balancer url|worker url</var>></code>
1804 container directive, the <var>url</var> argument is not required. As a side
1805 effect the respective balancer or worker gets created. This can be useful
1806 when doing reverse proxying via a
1807 <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> instead of a
1808 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.</p>
1810 <div class="example"><pre class="prettyprint lang-config">
1811 <Proxy balancer://hotcluster>
1812 BalancerMember http://www2.example.com:8080 loadfactor=1
1813 BalancerMember http://www3.example.com:8080 loadfactor=2
1814 ProxySet lbmethod=bytraffic
1819 <pre class="prettyprint lang-config">
1820 <Proxy http://backend>
1821 ProxySet keepalive=On
1826 <pre class="prettyprint lang-config">
1827 ProxySet balancer://foo lbmethod=bytraffic timeout=15
1831 <pre class="prettyprint lang-config">
1832 ProxySet ajp://backend:7001 timeout=15
1836 <div class="warning"><h3>Warning</h3>
1837 <p>Keep in mind that the same parameter key can have a different meaning
1838 depending whether it is applied to a balancer or a worker as shown by the two
1839 examples above regarding timeout.</p>
1844 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1845 <div class="directive-section"><h2><a name="ProxySourceAddress" id="ProxySourceAddress">ProxySourceAddress</a> <a name="proxysourceaddress" id="proxysourceaddress">Directive</a></h2>
1846 <table class="directive">
1847 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Set local IP address for outgoing proxy connections</td></tr>
1848 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxySourceAddress <var>address</var></code></td></tr>
1849 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1850 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1851 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1852 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in version 2.3.9 and later</td></tr>
1854 <p>This directive allows to set a specific local address to bind to when connecting
1855 to a backend server.</p>
1858 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1859 <div class="directive-section"><h2><a name="ProxyStatus" id="ProxyStatus">ProxyStatus</a> <a name="proxystatus" id="proxystatus">Directive</a></h2>
1860 <table class="directive">
1861 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Show Proxy LoadBalancer status in mod_status</td></tr>
1862 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyStatus Off|On|Full</code></td></tr>
1863 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyStatus Off</code></td></tr>
1864 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1865 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1866 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1868 <p>This directive determines whether or not proxy
1869 loadbalancer status data is displayed via the <code class="module"><a href="../mod/mod_status.html">mod_status</a></code>
1870 server-status page.</p>
1871 <div class="note"><h3>Note</h3>
1872 <p><strong>Full</strong> is synonymous with <strong>On</strong></p>
1877 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1878 <div class="directive-section"><h2><a name="ProxyTimeout" id="ProxyTimeout">ProxyTimeout</a> <a name="proxytimeout" id="proxytimeout">Directive</a></h2>
1879 <table class="directive">
1880 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Network timeout for proxied requests</td></tr>
1881 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyTimeout <var>seconds</var></code></td></tr>
1882 <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>
1883 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1884 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1885 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1887 <p>This directive allows a user to specifiy a timeout on proxy requests.
1888 This is useful when you have a slow/buggy appserver which hangs, and you
1889 would rather just return a timeout and fail gracefully instead of waiting
1890 however long it takes the server to return.</p>
1893 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1894 <div class="directive-section"><h2><a name="ProxyVia" id="ProxyVia">ProxyVia</a> <a name="proxyvia" id="proxyvia">Directive</a></h2>
1895 <table class="directive">
1896 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Information provided in the <code>Via</code> HTTP response
1897 header for proxied requests</td></tr>
1898 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyVia On|Off|Full|Block</code></td></tr>
1899 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyVia Off</code></td></tr>
1900 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1901 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1902 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1904 <p>This directive controls the use of the <code>Via:</code> HTTP
1905 header by the proxy. Its intended use is to control the flow of
1906 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
1907 14.45 for an explanation of <code>Via:</code> header lines.</p>
1910 <li>If set to <code>Off</code>, which is the default, no special processing
1911 is performed. If a request or reply contains a <code>Via:</code> header,
1912 it is passed through unchanged.</li>
1914 <li>If set to <code>On</code>, each request and reply will get a
1915 <code>Via:</code> header line added for the current host.</li>
1917 <li>If set to <code>Full</code>, each generated <code>Via:</code> header
1918 line will additionally have the Apache httpd server version shown as a
1919 <code>Via:</code> comment field.</li>
1921 <li>If set to <code>Block</code>, every proxy request will have all its
1922 <code>Via:</code> header lines removed. No new <code>Via:</code> header will
1928 <div class="bottomlang">
1929 <p><span>Available Languages: </span><a href="../en/mod/mod_proxy.html" title="English"> en </a> |
1930 <a href="../fr/mod/mod_proxy.html" hreflang="fr" rel="alternate" title="Français"> fr </a> |
1931 <a href="../ja/mod/mod_proxy.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a></p>
1932 </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>
1933 <script type="text/javascript"><!--//--><![CDATA[//><!--
1934 var comments_shortname = 'httpd';
1935 var comments_identifier = 'http://httpd.apache.org/docs/trunk/mod/mod_proxy.html';
1937 if (w.location.hostname.toLowerCase() == "httpd.apache.org") {
1938 d.write('<div id="comments_thread"><\/div>');
1939 var s = d.createElement('script');
1940 s.type = 'text/javascript';
1942 s.src = 'https://comments.apache.org/show_comments.lua?site=' + comments_shortname + '&page=' + comments_identifier;
1943 (d.getElementsByTagName('head')[0] || d.getElementsByTagName('body')[0]).appendChild(s);
1946 d.write('<div id="comments_thread">Comments are disabled for this page at the moment.<\/div>');
1948 })(window, document);
1949 //--><!]]></script></div><div id="footer">
1950 <p class="apache">Copyright 2013 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>
1951 <p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/quickreference.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[//><!--
1952 if (typeof(prettyPrint) !== 'undefined') {