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19 <p class="apache">Apache HTTP Server Version 2.5</p>
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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>
75 <tr><td>WS and WSS (Web-sockets)</td><td><code class="module"><a href="../mod/mod_proxy_wstunnel.html">mod_proxy_wstunnel</a></code></td></tr>
80 <p>In addition, extended features are provided by other modules.
81 Caching is provided by <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code> and related
82 modules. The ability to contact remote servers using the SSL/TLS
83 protocol is provided by the <code>SSLProxy*</code> directives of
84 <code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code>. These additional modules will need
85 to be loaded and configured to take advantage of these features.</p>
87 <div id="quickview"><h3 class="directives">Directives</h3>
89 <li><img alt="" src="../images/down.gif" /> <a href="#balancergrowth">BalancerGrowth</a></li>
90 <li><img alt="" src="../images/down.gif" /> <a href="#balancerinherit">BalancerInherit</a></li>
91 <li><img alt="" src="../images/down.gif" /> <a href="#balancermember">BalancerMember</a></li>
92 <li><img alt="" src="../images/down.gif" /> <a href="#balancerpersist">BalancerPersist</a></li>
93 <li><img alt="" src="../images/down.gif" /> <a href="#noproxy">NoProxy</a></li>
94 <li><img alt="" src="../images/down.gif" /> <a href="#proxy"><Proxy></a></li>
95 <li><img alt="" src="../images/down.gif" /> <a href="#proxyaddheaders">ProxyAddHeaders</a></li>
96 <li><img alt="" src="../images/down.gif" /> <a href="#proxybadheader">ProxyBadHeader</a></li>
97 <li><img alt="" src="../images/down.gif" /> <a href="#proxyblock">ProxyBlock</a></li>
98 <li><img alt="" src="../images/down.gif" /> <a href="#proxydomain">ProxyDomain</a></li>
99 <li><img alt="" src="../images/down.gif" /> <a href="#proxyerroroverride">ProxyErrorOverride</a></li>
100 <li><img alt="" src="../images/down.gif" /> <a href="#proxyiobuffersize">ProxyIOBufferSize</a></li>
101 <li><img alt="" src="../images/down.gif" /> <a href="#proxymatch"><ProxyMatch></a></li>
102 <li><img alt="" src="../images/down.gif" /> <a href="#proxymaxforwards">ProxyMaxForwards</a></li>
103 <li><img alt="" src="../images/down.gif" /> <a href="#proxypass">ProxyPass</a></li>
104 <li><img alt="" src="../images/down.gif" /> <a href="#proxypassinherit">ProxyPassInherit</a></li>
105 <li><img alt="" src="../images/down.gif" /> <a href="#proxypassinterpolateenv">ProxyPassInterpolateEnv</a></li>
106 <li><img alt="" src="../images/down.gif" /> <a href="#proxypassmatch">ProxyPassMatch</a></li>
107 <li><img alt="" src="../images/down.gif" /> <a href="#proxypassreverse">ProxyPassReverse</a></li>
108 <li><img alt="" src="../images/down.gif" /> <a href="#proxypassreversecookiedomain">ProxyPassReverseCookieDomain</a></li>
109 <li><img alt="" src="../images/down.gif" /> <a href="#proxypassreversecookiepath">ProxyPassReverseCookiePath</a></li>
110 <li><img alt="" src="../images/down.gif" /> <a href="#proxypreservehost">ProxyPreserveHost</a></li>
111 <li><img alt="" src="../images/down.gif" /> <a href="#proxyreceivebuffersize">ProxyReceiveBufferSize</a></li>
112 <li><img alt="" src="../images/down.gif" /> <a href="#proxyremote">ProxyRemote</a></li>
113 <li><img alt="" src="../images/down.gif" /> <a href="#proxyremotematch">ProxyRemoteMatch</a></li>
114 <li><img alt="" src="../images/down.gif" /> <a href="#proxyrequests">ProxyRequests</a></li>
115 <li><img alt="" src="../images/down.gif" /> <a href="#proxyset">ProxySet</a></li>
116 <li><img alt="" src="../images/down.gif" /> <a href="#proxysourceaddress">ProxySourceAddress</a></li>
117 <li><img alt="" src="../images/down.gif" /> <a href="#proxystatus">ProxyStatus</a></li>
118 <li><img alt="" src="../images/down.gif" /> <a href="#proxytimeout">ProxyTimeout</a></li>
119 <li><img alt="" src="../images/down.gif" /> <a href="#proxyvia">ProxyVia</a></li>
123 <li><img alt="" src="../images/down.gif" /> <a href="#forwardreverse">Forward Proxies and Reverse
124 Proxies/Gateways</a></li>
125 <li><img alt="" src="../images/down.gif" /> <a href="#examples">Basic Examples</a></li>
126 <li><img alt="" src="../images/down.gif" /> <a href="#handler">Access via Handler</a></li>
127 <li><img alt="" src="../images/down.gif" /> <a href="#workers">Workers</a></li>
128 <li><img alt="" src="../images/down.gif" /> <a href="#access">Controlling access to your proxy</a></li>
129 <li><img alt="" src="../images/down.gif" /> <a href="#startup">Slow Startup</a></li>
130 <li><img alt="" src="../images/down.gif" /> <a href="#intranet">Intranet Proxy</a></li>
131 <li><img alt="" src="../images/down.gif" /> <a href="#envsettings">Protocol Adjustments</a></li>
132 <li><img alt="" src="../images/down.gif" /> <a href="#request-bodies">Request Bodies</a></li>
133 <li><img alt="" src="../images/down.gif" /> <a href="#x-headers">Reverse Proxy Request Headers</a></li>
134 </ul><h3>See also</h3>
136 <li><code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code></li>
137 <li><code class="module"><a href="../mod/mod_proxy_ajp.html">mod_proxy_ajp</a></code></li>
138 <li><code class="module"><a href="../mod/mod_proxy_connect.html">mod_proxy_connect</a></code></li>
139 <li><code class="module"><a href="../mod/mod_proxy_fcgi.html">mod_proxy_fcgi</a></code></li>
140 <li><code class="module"><a href="../mod/mod_proxy_ftp.html">mod_proxy_ftp</a></code></li>
141 <li><code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code></li>
142 <li><code class="module"><a href="../mod/mod_proxy_scgi.html">mod_proxy_scgi</a></code></li>
143 <li><code class="module"><a href="../mod/mod_proxy_wstunnel.html">mod_proxy_wstunnel</a></code></li>
144 <li><code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code></li>
145 <li><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></li>
146 </ul><ul class="seealso"><li><a href="#comments_section">Comments</a></li></ul></div>
147 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
148 <div class="section">
149 <h2><a name="forwardreverse" id="forwardreverse">Forward Proxies and Reverse
150 Proxies/Gateways</a></h2>
151 <p>Apache HTTP Server can be configured in both a <dfn>forward</dfn> and
152 <dfn>reverse</dfn> proxy (also known as <dfn>gateway</dfn>) mode.</p>
154 <p>An ordinary <dfn>forward proxy</dfn> is an intermediate
155 server that sits between the client and the <em>origin
156 server</em>. In order to get content from the origin server,
157 the client sends a request to the proxy naming the origin server
158 as the target and the proxy then requests the content from the
159 origin server and returns it to the client. The client must be
160 specially configured to use the forward proxy to access other
163 <p>A typical usage of a forward proxy is to provide Internet
164 access to internal clients that are otherwise restricted by a
165 firewall. The forward proxy can also use caching (as provided
166 by <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code>) to reduce network usage.</p>
168 <p>The forward proxy is activated using the <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> directive. Because
169 forward proxies allow clients to access arbitrary sites through
170 your server and to hide their true origin, it is essential that
171 you <a href="#access">secure your server</a> so that only
172 authorized clients can access the proxy before activating a
175 <p>A <dfn>reverse proxy</dfn> (or <dfn>gateway</dfn>), by
176 contrast, appears to the client just like an ordinary web
177 server. No special configuration on the client is necessary.
178 The client makes ordinary requests for content in the name-space
179 of the reverse proxy. The reverse proxy then decides where to
180 send those requests, and returns the content as if it was itself
183 <p>A typical usage of a reverse proxy is to provide Internet
184 users access to a server that is behind a firewall. Reverse
185 proxies can also be used to balance load among several back-end
186 servers, or to provide caching for a slower back-end server.
187 In addition, reverse proxies can be used simply to bring
188 several servers into the same URL space.</p>
190 <p>A reverse proxy is activated using the <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive or the
191 <code>[P]</code> flag to the <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> directive. It is
192 <strong>not</strong> necessary to turn <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> on in order to
193 configure a reverse proxy.</p>
194 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
195 <div class="section">
196 <h2><a name="examples" id="examples">Basic Examples</a></h2>
198 <p>The examples below are only a very basic idea to help you
199 get started. Please read the documentation on the individual
202 <p>In addition, if you wish to have caching enabled, consult
203 the documentation from <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code>.</p>
205 <div class="example"><h3>Reverse Proxy</h3><pre class="prettyprint lang-config">ProxyPass /foo http://foo.example.com/bar
206 ProxyPassReverse /foo http://foo.example.com/bar</pre>
209 <div class="example"><h3>Forward Proxy</h3><pre class="prettyprint lang-config">ProxyRequests On
213 Require host internal.example.com
216 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
217 <div class="section">
218 <h2><a name="handler" id="handler">Access via Handler</a></h2>
220 <p>You can also force a request to be handled as a reverse-proxy
221 request, by creating a suitable Handler pass-through. The example
222 configuration below will pass all requests for PHP scripts to the
223 specified FastCGI server using reverse proxy:
226 <div class="example"><h3>Reverse Proxy PHP scripts</h3><pre class="prettyprint lang-config"><FilesMatch \.php$>
227 SetHandler "proxy:unix:/path/to/app.sock|fcgi://localhost/"
228 </FilesMatch></pre>
231 <p>This feature is available in Apache HTTP Server 2.4.10 and later.</p>
233 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
234 <div class="section">
235 <h2><a name="workers" id="workers">Workers</a></h2>
236 <p>The proxy manages the configuration of origin servers and their
237 communication parameters in objects called <dfn>workers</dfn>.
238 There are two built-in workers, the default forward proxy worker and the
239 default reverse proxy worker. Additional workers can be configured
242 <p>The two default workers have a fixed configuration
243 and will be used if no other worker matches the request.
244 They do not use HTTP Keep-Alive or connection pooling.
245 The TCP connections to the origin server will instead be
246 opened and closed for each request.</p>
248 <p>Explicitly configured workers are identified by their URL.
249 They are usually created and configured using
250 <code class="directive"><a href="#proxypass">ProxyPass</a></code> or
251 <code class="directive"><a href="#proxypassmatch">ProxyPassMatch</a></code> when used
252 for a reverse proxy:</p>
254 <pre class="prettyprint lang-config">ProxyPass /example http://backend.example.com connectiontimeout=5 timeout=30</pre>
257 <p>This will create a worker associated with the origin server URL
258 <code>http://backend.example.com</code> and using the given timeout
259 values. When used in a forward proxy, workers are usually defined
260 via the <code class="directive"><a href="#proxyset">ProxySet</a></code> directive:</p>
262 <pre class="prettyprint lang-config">ProxySet http://backend.example.com connectiontimeout=5 timeout=30</pre>
265 <p>or alternatively using <code class="directive"><a href="#proxy">Proxy</a></code>
266 and <code class="directive"><a href="#proxyset">ProxySet</a></code>:</p>
268 <pre class="prettyprint lang-config"><Proxy http://backend.example.com>
269 ProxySet connectiontimeout=5 timeout=30
273 <p>Using explicitly configured workers in the forward mode is
274 not very common, because forward proxies usually communicate with many
275 different origin servers. Creating explicit workers for some of the
276 origin servers can still be useful, if they are used very often.
277 Explicitly configured workers have no concept of forward or reverse
278 proxying by themselves. They encapsulate a common concept of
279 communication with origin servers. A worker created by
280 <code class="directive"><a href="#proxypass">ProxyPass</a></code> for use in a
281 reverse proxy will be also used for forward proxy requests whenever
282 the URL to the origin server matches the worker URL and vice versa.</p>
284 <p>The URL identifying a direct worker is the URL of its
285 origin server including any path components given:</p>
287 <pre class="prettyprint lang-config">ProxyPass /examples http://backend.example.com/examples
288 ProxyPass /docs http://backend.example.com/docs</pre>
291 <p>This example defines two different workers, each using a separate
292 connection pool and configuration.</p>
294 <div class="warning"><h3>Worker Sharing</h3>
295 <p>Worker sharing happens if the worker URLs overlap, which occurs when
296 the URL of some worker is a leading substring of the URL of another
297 worker defined later in the configuration file. In the following example</p>
299 <pre class="prettyprint lang-config">ProxyPass /apps http://backend.example.com/ timeout=60
300 ProxyPass /examples http://backend.example.com/examples timeout=10</pre>
303 <p>the second worker isn't actually created. Instead the first
304 worker is used. The benefit is, that there is only one connection pool,
305 so connections are more often reused. Note that all configuration attributes
306 given explicitly for the later worker will be ignored. This will be logged
307 as a warning. In the above example the resulting timeout value
308 for the URL <code>/examples</code> will be <code>60</code> instead
309 of <code>10</code>!</p>
311 <p>If you want to avoid worker sharing, sort your worker definitions
312 by URL length, starting with the longest worker URLs. If you want to maximize
313 worker sharing use the reverse sort order. See also the related warning about
314 ordering <code class="directive"><a href="#proxypass">ProxyPass</a></code> directives.</p>
318 <p>Explicitly configured workers come in two flavors:
319 <dfn>direct workers</dfn> and <dfn>(load) balancer workers</dfn>.
320 They support many important configuration attributes which are
321 described below in the <code class="directive"><a href="#proxypass">ProxyPass</a></code>
322 directive. The same attributes can also be set using
323 <code class="directive"><a href="#proxyset">ProxySet</a></code>.</p>
325 <p>The set of options available for a direct worker
326 depends on the protocol, which is specified in the origin server URL.
327 Available protocols include <code>ajp</code>, <code>fcgi</code>,
328 <code>ftp</code>, <code>http</code> and <code>scgi</code>.</p>
330 <p>Balancer workers are virtual workers that use direct workers known
331 as their members to actually handle the requests. Each balancer can
332 have multiple members. When it handles a request, it chooses a member
333 based on the configured load balancing algorithm.</p>
335 <p>A balancer worker is created if its worker URL uses
336 <code>balancer</code> as the protocol scheme.
337 The balancer URL uniquely identifies the balancer worker.
338 Members are added to a balancer using
339 <code class="directive"><a href="#balancermember">BalancerMember</a></code>.</p>
341 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
342 <div class="section">
343 <h2><a name="access" id="access">Controlling access to your proxy</a></h2>
344 <p>You can control who can access your proxy via the <code class="directive"><a href="#proxy"><Proxy></a></code> control block as in
345 the following example:</p>
347 <pre class="prettyprint lang-config"><Proxy *>
352 <p>For more information on access control directives, see
353 <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code>.</p>
355 <p>Strictly limiting access is essential if you are using a
356 forward proxy (using the <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> directive).
357 Otherwise, your server can be used by any client to access
358 arbitrary hosts while hiding his or her true identity. This is
359 dangerous both for your network and for the Internet at large.
360 When using a reverse proxy (using the <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive with
361 <code>ProxyRequests Off</code>), access control is less
362 critical because clients can only contact the hosts that you
363 have specifically configured.</p>
365 <p><strong>See Also</strong> the <a href="mod_proxy_http.html#env">Proxy-Chain-Auth</a> environment variable.</p>
367 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
368 <div class="section">
369 <h2><a name="startup" id="startup">Slow Startup</a></h2>
370 <p>If you're using the <code class="directive"><a href="#proxyblock">ProxyBlock</a></code> directive, hostnames' IP addresses are looked up
371 and cached during startup for later match test. This may take a few
372 seconds (or more) depending on the speed with which the hostname lookups
374 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
375 <div class="section">
376 <h2><a name="intranet" id="intranet">Intranet Proxy</a></h2>
377 <p>An Apache httpd proxy server situated in an intranet needs to forward
378 external requests through the company's firewall (for this, configure
379 the <code class="directive"><a href="#proxyremote">ProxyRemote</a></code> directive
380 to forward the respective <var>scheme</var> to the firewall proxy).
381 However, when it has to
382 access resources within the intranet, it can bypass the firewall when
383 accessing hosts. The <code class="directive"><a href="#noproxy">NoProxy</a></code>
384 directive is useful for specifying which hosts belong to the intranet and
385 should be accessed directly.</p>
387 <p>Users within an intranet tend to omit the local domain name from their
388 WWW requests, thus requesting "http://somehost/" instead of
389 <code>http://somehost.example.com/</code>. Some commercial proxy servers
390 let them get away with this and simply serve the request, implying a
391 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
392 a redirect response and send the client to the correct, fully qualified,
393 server address. This is the preferred method since the user's bookmark
394 files will then contain fully qualified hosts.</p>
395 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
396 <div class="section">
397 <h2><a name="envsettings" id="envsettings">Protocol Adjustments</a></h2>
398 <p>For circumstances where <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> is sending
399 requests to an origin server that doesn't properly implement
400 keepalives or HTTP/1.1, there are two <a href="../env.html">environment variables</a> that can force the
401 request to use HTTP/1.0 with no keepalive. These are set via the
402 <code class="directive"><a href="../mod/mod_env.html#setenv">SetEnv</a></code> directive.</p>
404 <p>These are the <code>force-proxy-request-1.0</code> and
405 <code>proxy-nokeepalive</code> notes.</p>
407 <pre class="prettyprint lang-config"><Location /buggyappserver/>
408 ProxyPass http://buggyappserver:7001/foo/
409 SetEnv force-proxy-request-1.0 1
410 SetEnv proxy-nokeepalive 1
411 </Location></pre>
414 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
415 <div class="section">
416 <h2><a name="request-bodies" id="request-bodies">Request Bodies</a></h2>
418 <p>Some request methods such as POST include a request body.
419 The HTTP protocol requires that requests which include a body
420 either use chunked transfer encoding or send a
421 <code>Content-Length</code> request header. When passing these
422 requests on to the origin server, <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code>
423 will always attempt to send the <code>Content-Length</code>. But
424 if the body is large and the original request used chunked
425 encoding, then chunked encoding may also be used in the upstream
426 request. You can control this selection using <a href="../env.html">environment variables</a>. Setting
427 <code>proxy-sendcl</code> ensures maximum compatibility with
428 upstream servers by always sending the
429 <code>Content-Length</code>, while setting
430 <code>proxy-sendchunked</code> minimizes resource usage by using
431 chunked encoding.</p>
433 <p>Under some circumstances, the server must spool request bodies
434 to disk to satisfy the requested handling of request bodies. For
435 example, this spooling will occur if the original body was sent with
436 chunked encoding (and is large), but the administrator has
437 asked for backend requests to be sent with Content-Length or as HTTP/1.0.
438 This spooling can also occur if the request body already has a
439 Content-Length header, but the server is configured to filter incoming
442 <p><code class="directive"><a href="../mod/core.html#limitrequestbody">LimitRequestBody</a></code> only applies to
443 request bodies that the server will spool to disk</p>
445 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
446 <div class="section">
447 <h2><a name="x-headers" id="x-headers">Reverse Proxy Request Headers</a></h2>
449 <p>When acting in a reverse-proxy mode (using the <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive, for example),
450 <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code> adds several request headers in
451 order to pass information to the origin server. These headers
455 <dt><code>X-Forwarded-For</code></dt>
456 <dd>The IP address of the client.</dd>
457 <dt><code>X-Forwarded-Host</code></dt>
458 <dd>The original host requested by the client in the <code>Host</code>
459 HTTP request header.</dd>
460 <dt><code>X-Forwarded-Server</code></dt>
461 <dd>The hostname of the proxy server.</dd>
464 <p>Be careful when using these headers on the origin server, since
465 they will contain more than one (comma-separated) value if the
466 original request already contained one of these headers. For
467 example, you can use <code>%{X-Forwarded-For}i</code> in the log
468 format string of the origin server to log the original clients IP
469 address, but you may get more than one address if the request
470 passes through several proxies.</p>
472 <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
473 other request headers.</p>
475 <p>Note: If you need to specify custom request headers to be
476 added to the forwarded request, use the
477 <code class="directive"><a href="../mod/mod_headers.html#requestheader">RequestHeader</a></code>
481 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
482 <div class="directive-section"><h2><a name="BalancerGrowth" id="BalancerGrowth">BalancerGrowth</a> <a name="balancergrowth" id="balancergrowth">Directive</a></h2>
483 <table class="directive">
484 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of additional Balancers that can be added Post-configuration</td></tr>
485 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>BalancerGrowth <var>#</var></code></td></tr>
486 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>BalancerGrowth 5</code></td></tr>
487 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
488 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
489 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
490 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>BalancerGrowth is only available in Apache HTTP Server 2.3.13
493 <p>This directive allows for growth potential in the number of
494 Balancers available for a virtualhost in addition to the
495 number pre-configured. It only takes effect if there is at
496 least 1 pre-configured Balancer.</p>
499 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
500 <div class="directive-section"><h2><a name="BalancerInherit" id="BalancerInherit">BalancerInherit</a> <a name="balancerinherit" id="balancerinherit">Directive</a></h2>
501 <table class="directive">
502 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Inherit proxy Balancers/Workers defined from the main server</td></tr>
503 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>BalancerInherit On|Off</code></td></tr>
504 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>BalancerInherit On</code></td></tr>
505 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
506 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
507 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
508 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>BalancerInherit is only available in Apache HTTP Server 2.4.5 and later.</td></tr>
510 <p>This directive will cause the current server/vhost to "inherit"
511 Balancers and Workers defined in the main server. This can cause issues and
512 inconsistent behavior if using the Balancer Manager for dynamic changes
513 and so should be disabled if using that feature.</p>
514 <p>The setting in the global server defines the default for all vhosts.</p>
515 <p>Disabling <code class="directive"><a href="#proxypassinherit">ProxyPassInherit</a></code> also disables BalancerInherit.</p>
518 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
519 <div class="directive-section"><h2><a name="BalancerMember" id="BalancerMember">BalancerMember</a> <a name="balancermember" id="balancermember">Directive</a></h2>
520 <table class="directive">
521 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Add a member to a load balancing group</td></tr>
522 <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>
523 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
524 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
525 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
527 <p>This directive adds a member to a load balancing group. It could be used
528 within a <code><Proxy <var>balancer://</var>...></code> container
529 directive, and can take any of the key value pair parameters available to
530 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directives.</p>
531 <p>One additional parameter is available only to <code class="directive">BalancerMember</code> directives:
532 <var>loadfactor</var>. This is the member load factor - a number between 1
533 (default) and 100, which defines the weighted load to be applied to the
534 member in question.</p>
535 <p>The <var>balancerurl</var> is only needed when not in <code><Proxy <var>balancer://</var>...></code>
536 container directive. It corresponds to the url of a balancer defined in
537 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.</p>
538 <p>The path component of the balancer URL in any
539 <code><Proxy <var>balancer://</var>...></code> container directive
541 <p>Trailing slashes should typically be removed from the URL of a
542 <code class="directive">BalancerMember</code>.</p>
545 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
546 <div class="directive-section"><h2><a name="BalancerPersist" id="BalancerPersist">BalancerPersist</a> <a name="balancerpersist" id="balancerpersist">Directive</a></h2>
547 <table class="directive">
548 <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>
549 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>BalancerPersist On|Off</code></td></tr>
550 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>BalancerPersist Off</code></td></tr>
551 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
552 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
553 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
554 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>BalancerPersist is only available in Apache HTTP Server 2.4.4 and later.</td></tr>
556 <p>This directive will cause the shared memory storage associated
557 with the balancers and balancer members to be persisted across
558 restarts. This allows these local changes to not be lost during the
559 normal restart/graceful state transitions.</p>
562 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
563 <div class="directive-section"><h2><a name="NoProxy" id="NoProxy">NoProxy</a> <a name="noproxy" id="noproxy">Directive</a></h2>
564 <table class="directive">
565 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Hosts, domains, or networks that will be connected to
567 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>NoProxy <var>host</var> [<var>host</var>] ...</code></td></tr>
568 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
569 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
570 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
572 <p>This directive is only useful for Apache httpd proxy servers within
573 intranets. The <code class="directive">NoProxy</code> directive specifies a
574 list of subnets, IP addresses, hosts and/or domains, separated by
575 spaces. A request to a host which matches one or more of these is
576 always served directly, without forwarding to the configured
577 <code class="directive"><a href="#proxyremote">ProxyRemote</a></code> proxy server(s).</p>
579 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">ProxyRemote * http://firewall.example.com:81
580 NoProxy .example.com 192.168.112.0/21</pre>
583 <p>The <var>host</var> arguments to the <code class="directive">NoProxy</code>
584 directive are one of the following type list:</p>
588 <dt><var><a name="domain" id="domain">Domain</a></var></dt>
590 <p>A <dfn>Domain</dfn> is a partially qualified DNS domain name, preceded
591 by a period. It represents a list of hosts which logically belong to the
592 same DNS domain or zone (<em>i.e.</em>, the suffixes of the hostnames are
593 all ending in <var>Domain</var>).</p>
595 <div class="example"><h3>Examples</h3><p><code>
599 <p>To distinguish <var>Domain</var>s from <var><a href="#hostname">Hostname</a></var>s (both syntactically and semantically; a DNS domain can
600 have a DNS A record, too!), <var>Domain</var>s are always written with a
603 <div class="note"><h3>Note</h3>
604 <p>Domain name comparisons are done without regard to the case, and
605 <var>Domain</var>s are always assumed to be anchored in the root of the
606 DNS tree, therefore two domains <code>.ExAmple.com</code> and
607 <code>.example.com.</code> (note the trailing period) are considered
608 equal. Since a domain comparison does not involve a DNS lookup, it is much
609 more efficient than subnet comparison.</p>
613 <dt><var><a name="subnet" id="subnet">SubNet</a></var></dt>
615 <p>A <dfn>SubNet</dfn> is a partially qualified internet address in
616 numeric (dotted quad) form, optionally followed by a slash and the netmask,
617 specified as the number of significant bits in the <var>SubNet</var>. It is
618 used to represent a subnet of hosts which can be reached over a common
619 network interface. In the absence of the explicit net mask it is assumed
620 that omitted (or zero valued) trailing digits specify the mask. (In this
621 case, the netmask can only be multiples of 8 bits wide.) Examples:</p>
624 <dt><code>192.168</code> or <code>192.168.0.0</code></dt>
625 <dd>the subnet 192.168.0.0 with an implied netmask of 16 valid bits
626 (sometimes used in the netmask form <code>255.255.0.0</code>)</dd>
627 <dt><code>192.168.112.0/21</code></dt>
628 <dd>the subnet <code>192.168.112.0/21</code> with a netmask of 21
629 valid bits (also used in the form <code>255.255.248.0</code>)</dd>
632 <p>As a degenerate case, a <em>SubNet</em> with 32 valid bits is the
633 equivalent to an <var><a href="#ipaddr">IPAddr</a></var>, while a <var>SubNet</var> with zero
634 valid bits (<em>e.g.</em>, 0.0.0.0/0) is the same as the constant
635 <var>_Default_</var>, matching any IP address.</p></dd>
638 <dt><var><a name="ipaddr" id="ipaddr">IPAddr</a></var></dt>
640 <p>A <dfn>IPAddr</dfn> represents a fully qualified internet address in
641 numeric (dotted quad) form. Usually, this address represents a host, but
642 there need not necessarily be a DNS domain name connected with the
644 <div class="example"><h3>Example</h3><p><code>
648 <div class="note"><h3>Note</h3>
649 <p>An <var>IPAddr</var> does not need to be resolved by the DNS system, so
650 it can result in more effective apache performance.</p>
654 <dt><var><a name="hostname" id="hostname">Hostname</a></var></dt>
656 <p>A <dfn>Hostname</dfn> is a fully qualified DNS domain name which can
657 be resolved to one or more <var><a href="#ipaddr">IPAddrs</a></var> via the
658 DNS domain name service. It represents a logical host (in contrast to
659 <var><a href="#domain">Domain</a></var>s, see above) and must be resolvable
660 to at least one <var><a href="#ipaddr">IPAddr</a></var> (or often to a list
661 of hosts with different <var><a href="#ipaddr">IPAddr</a></var>s).</p>
663 <div class="example"><h3>Examples</h3><p><code>
664 prep.ai.example.edu<br />
668 <div class="note"><h3>Note</h3>
669 <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
670 DNS lookup can be avoided. Name resolution in Apache httpd can take a remarkable
671 deal of time when the connection to the name server uses a slow PPP
673 <p><var>Hostname</var> comparisons are done without regard to the case,
674 and <var>Hostname</var>s are always assumed to be anchored in the root
675 of the DNS tree, therefore two hosts <code>WWW.ExAmple.com</code>
676 and <code>www.example.com.</code> (note the trailing period) are
677 considered equal.</p>
683 <li><a href="../dns-caveats.html">DNS Issues</a></li>
686 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
687 <div class="directive-section"><h2><a name="Proxy" id="Proxy"><Proxy></a> <a name="proxy" id="proxy">Directive</a></h2>
688 <table class="directive">
689 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Container for directives applied to proxied resources</td></tr>
690 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Proxy <var>wildcard-url</var>> ...</Proxy></code></td></tr>
691 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
692 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
693 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
695 <p>Directives placed in <code class="directive"><Proxy></code>
696 sections apply only to matching proxied content. Shell-style wildcards are
699 <p>For example, the following will allow only hosts in
700 <code>yournetwork.example.com</code> to access content via your proxy
703 <pre class="prettyprint lang-config"><Proxy *>
704 Require host yournetwork.example.com
708 <p>The following example will process all files in the <code>foo</code>
709 directory of <code>example.com</code> through the <code>INCLUDES</code>
710 filter when they are sent through the proxy server:</p>
712 <pre class="prettyprint lang-config"><Proxy http://example.com/foo/*>
713 SetOutputFilter INCLUDES
717 <div class="note"><h3>Differences from the Location configuration section</h3>
718 <p>A backend URL matches the configuration section if it begins with the
719 the <var>wildcard-url</var> string, even if the last path segment in the
720 directive only matches a prefix of the backend URL. For example,
721 <Proxy http://example.com/foo> matches all of
722 http://example.com/foo, http://example.com/foo/bar, and
723 http://example.com/foobar. The matching of the final URL differs
724 from the behavior of the <code class="directive"><a href="../mod/core.html#location"><Location></a></code> section, which for purposes of this note
725 treats the final path component as if it ended in a slash.</p>
726 <p>For more control over the matching, see <code class="directive"><ProxyMatch></code>.</p>
732 <li><code class="directive"><a href="#proxymatch"><ProxyMatch></a></code></li>
735 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
736 <div class="directive-section"><h2><a name="ProxyAddHeaders" id="ProxyAddHeaders">ProxyAddHeaders</a> <a name="proxyaddheaders" id="proxyaddheaders">Directive</a></h2>
737 <table class="directive">
738 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Add proxy information in X-Forwarded-* headers</td></tr>
739 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyAddHeaders Off|On</code></td></tr>
740 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyAddHeaders On</code></td></tr>
741 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
742 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
743 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
744 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in version 2.3.10 and later</td></tr>
746 <p>This directive determines whether or not proxy related information should be passed to the
747 backend server through X-Forwarded-For, X-Forwarded-Host and X-Forwarded-Server HTTP headers.</p>
748 <div class="note"><h3>Effectiveness</h3>
749 <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>
753 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
754 <div class="directive-section"><h2><a name="ProxyBadHeader" id="ProxyBadHeader">ProxyBadHeader</a> <a name="proxybadheader" id="proxybadheader">Directive</a></h2>
755 <table class="directive">
756 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines how to handle bad header lines in a
758 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyBadHeader IsError|Ignore|StartBody</code></td></tr>
759 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyBadHeader IsError</code></td></tr>
760 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
761 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
762 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
764 <p>The <code class="directive">ProxyBadHeader</code> directive determines the
765 behaviour of <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> if it receives syntactically invalid
766 response header lines (<em>i.e.</em> containing no colon) from the origin
767 server. The following arguments are possible:</p>
770 <dt><code>IsError</code></dt>
771 <dd>Abort the request and end up with a 502 (Bad Gateway) response. This is
772 the default behaviour.</dd>
774 <dt><code>Ignore</code></dt>
775 <dd>Treat bad header lines as if they weren't sent.</dd>
777 <dt><code>StartBody</code></dt>
778 <dd>When receiving the first bad header line, finish reading the headers and
779 treat the remainder as body. This helps to work around buggy backend servers
780 which forget to insert an empty line between the headers and the body.</dd>
784 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
785 <div class="directive-section"><h2><a name="ProxyBlock" id="ProxyBlock">ProxyBlock</a> <a name="proxyblock" id="proxyblock">Directive</a></h2>
786 <table class="directive">
787 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Disallow proxy requests to certain hosts</td></tr>
788 <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>
789 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
790 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
791 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
793 <p>The <code class="directive">ProxyBlock</code> directive can be used to
794 block FTP or HTTP access to certain hosts via the proxy, based on
795 a full or partial hostname match, or, if applicable, an IP address
798 <p>Each of the arguments to the <code class="directive">ProxyBlock</code>
799 directive can be either <code>*</code> or a alphanumeric string.
800 At startup, the module will attempt to resolve every alphanumeric
801 string from a DNS name to a set of IP addresses, but any DNS errors
804 <p>If an asterisk "<code>*</code>" argument is specified,
805 <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> will deny access to all FTP or HTTP
808 <p>Otherwise, for any request for an HTTP or FTP resource via the
809 proxy, <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> will check the hostname of the
810 request URI against each specified string. If a partial string
811 match is found, access is denied. If no matches against hostnames
812 are found, and a remote (forward) proxy is configured using
813 <code class="directive">ProxyRemote</code> or
814 <code class="directive">ProxyRemoteMatch</code>, access is allowed. If no
815 remote (forward) proxy is configured, the IP address of the
816 hostname from the URI is compared against all resolved IP
817 addresses determined at startup. Access is denied if any match is
820 <p>Note that the DNS lookups may slow down the startup time of the
823 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">ProxyBlock news.example.com auctions.example.com friends.example.com</pre>
826 <p>Note that <code>example</code> would also be sufficient to match any
829 <p>Hosts would also be matched if referenced by IP address.</p>
831 <p>Note also that</p>
833 <pre class="prettyprint lang-config">ProxyBlock *</pre>
836 <p>blocks connections to all sites.</p>
839 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
840 <div class="directive-section"><h2><a name="ProxyDomain" id="ProxyDomain">ProxyDomain</a> <a name="proxydomain" id="proxydomain">Directive</a></h2>
841 <table class="directive">
842 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Default domain name for proxied requests</td></tr>
843 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyDomain <var>Domain</var></code></td></tr>
844 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
845 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
846 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
848 <p>This directive is only useful for Apache httpd proxy servers within
849 intranets. The <code class="directive">ProxyDomain</code> directive specifies
850 the default domain which the apache proxy server will belong to. If a
851 request to a host without a domain name is encountered, a redirection
852 response to the same host with the configured <var>Domain</var> appended
853 will be generated.</p>
855 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config"> ProxyRemote * http://firewall.example.com:81<br />
856 NoProxy .example.com 192.168.112.0/21<br />
857 ProxyDomain .example.com</pre>
861 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
862 <div class="directive-section"><h2><a name="ProxyErrorOverride" id="ProxyErrorOverride">ProxyErrorOverride</a> <a name="proxyerroroverride" id="proxyerroroverride">Directive</a></h2>
863 <table class="directive">
864 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Override error pages for proxied content</td></tr>
865 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyErrorOverride On|Off</code></td></tr>
866 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyErrorOverride Off</code></td></tr>
867 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
868 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
869 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
871 <p>This directive is useful for reverse-proxy setups, where you want to
872 have a common look and feel on the error pages seen by the end user.
873 This also allows for included files (via
874 <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>'s SSI) to get
875 the error code and act accordingly (default behavior would display
876 the error page of the proxied server, turning this on shows the SSI
879 <p>This directive does not affect the processing of informational (1xx),
880 normal success (2xx), or redirect (3xx) responses.</p>
883 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
884 <div class="directive-section"><h2><a name="ProxyIOBufferSize" id="ProxyIOBufferSize">ProxyIOBufferSize</a> <a name="proxyiobuffersize" id="proxyiobuffersize">Directive</a></h2>
885 <table class="directive">
886 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine size of internal data throughput buffer</td></tr>
887 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyIOBufferSize <var>bytes</var></code></td></tr>
888 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyIOBufferSize 8192</code></td></tr>
889 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
890 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
891 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
893 <p>The <code class="directive">ProxyIOBufferSize</code> directive adjusts the size
894 of the internal buffer, which is used as a scratchpad for the data between
895 input and output. The size must be at least <code>512</code>.</p>
897 <p>In almost every case there's no reason to change that value.</p>
899 <p>If used with AJP this directive sets the maximum AJP packet size in
900 bytes. Values larger than 65536 are set to 65536. If you change it from
901 the default, you must also change the <code>packetSize</code> attribute of
902 your AJP connector on the Tomcat side! The attribute
903 <code>packetSize</code> is only available in Tomcat <code>5.5.20+</code>
904 and <code>6.0.2+</code></p>
906 <p>Normally it is not necessary to change the maximum packet size.
907 Problems with the default value have been reported when sending
908 certificates or certificate chains.</p>
912 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
913 <div class="directive-section"><h2><a name="ProxyMatch" id="ProxyMatch"><ProxyMatch></a> <a name="proxymatch" id="proxymatch">Directive</a></h2>
914 <table class="directive">
915 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Container for directives applied to regular-expression-matched
916 proxied resources</td></tr>
917 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><ProxyMatch <var>regex</var>> ...</ProxyMatch></code></td></tr>
918 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
919 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
920 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
922 <p>The <code class="directive"><ProxyMatch></code> directive is
923 identical to the <code class="directive"><a href="#proxy"><Proxy></a></code> directive, except it matches URLs
924 using <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expressions</a>.</p>
926 <p>From 2.4.8 onwards, named groups and backreferences are captured and
927 written to the environment with the corresponding name prefixed with
928 "MATCH_" and in upper case. This allows elements of URLs to be referenced
929 from within <a href="../expr.html">expressions</a> and modules like
930 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
931 (unnamed) backreferences are ignored. Use named groups instead.</p>
933 <pre class="prettyprint lang-config"><ProxyMatch ^http://(?<sitename>[^/]+)>
934 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
935 </ProxyMatch></pre>
940 <li><code class="directive"><a href="#proxy"><Proxy></a></code></li>
943 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
944 <div class="directive-section"><h2><a name="ProxyMaxForwards" id="ProxyMaxForwards">ProxyMaxForwards</a> <a name="proxymaxforwards" id="proxymaxforwards">Directive</a></h2>
945 <table class="directive">
946 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximium number of proxies that a request can be forwarded
948 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyMaxForwards <var>number</var></code></td></tr>
949 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyMaxForwards -1</code></td></tr>
950 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
951 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
952 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
954 <p>The <code class="directive">ProxyMaxForwards</code> directive specifies the
955 maximum number of proxies through which a request may pass, if there's no
956 <code>Max-Forwards</code> header supplied with the request. This may
957 be set to prevent infinite proxy loops, or a DoS attack.</p>
959 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">ProxyMaxForwards 15</pre>
962 <p>Note that setting <code class="directive">ProxyMaxForwards</code> is a
963 violation of the HTTP/1.1 protocol (RFC2616), which forbids a Proxy
964 setting <code>Max-Forwards</code> if the Client didn't set it.
965 Earlier Apache httpd versions would always set it. A negative
966 <code class="directive">ProxyMaxForwards</code> value, including the
967 default -1, gives you protocol-compliant behaviour, but may
968 leave you open to loops.</p>
971 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
972 <div class="directive-section"><h2><a name="ProxyPass" id="ProxyPass">ProxyPass</a> <a name="proxypass" id="proxypass">Directive</a></h2>
973 <table class="directive">
974 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maps remote servers into the local server URL-space</td></tr>
975 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPass [<var>path</var>] !|<var>url</var> [<var>key=value</var>
976 <var>[key=value</var> ...]] [nocanon] [interpolate] [noquery]</code></td></tr>
977 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
978 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
979 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
981 <p>This directive allows remote servers to be mapped into the
982 space of the local server; the local server does not act as a
983 proxy in the conventional sense, but appears to be a mirror of the
984 remote server. The local server is often called a <dfn>reverse
985 proxy</dfn> or <dfn>gateway</dfn>. The <var>path</var> is the name of
986 a local virtual path; <var>url</var> is a partial URL for the
987 remote server and cannot include a query string.</p>
989 <div class="note"><strong>Note: </strong>This directive cannot be used within a
990 <code><Directory></code> context.</div>
992 <div class="warning">The <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> directive should
993 usually be set <strong>off</strong> when using
994 <code class="directive">ProxyPass</code>.</div>
996 <p>Support for using a Unix Domain Socket is available by using a url target
997 which prepends <code>unix:/path/lis.sock|</code>. For example, to proxy
998 HTTP and target the UDS at /home/www/socket you would use
999 <code>unix:/home/www.socket|http://localhost/whatever/</code>. Since
1000 the socket is local, the hostname used (in this case <code>localhost</code>)
1001 is moot, but it is passed as the Host: header value of the request.</p>
1003 <div class="note"><strong>Note:</strong> The path associated with the <code>unix:</code>
1004 URL is <code class="directive">DefaultRuntimeDir</code> aware.</div>
1006 <div class="note"><strong>Note:</strong> <code class="directive">RewriteRule</code> requires
1007 the <code>[P,NE]</code> option to prevent the <code>'|'</code> character
1008 from being escaped.</div>
1010 <p>Suppose the local server has address <code>http://example.com/</code>;
1013 <pre class="prettyprint lang-config"><Location /mirror/foo/>
1014 ProxyPass http://backend.example.com/
1015 </Location></pre>
1018 <p>will cause a local request for
1019 <code>http://example.com/mirror/foo/bar</code> to be internally converted
1020 into a proxy request to <code>http://backend.example.com/bar</code>.</p>
1022 <p>The following alternative syntax is possible, however it can carry a
1023 performance penalty when present in very large numbers. The advantage of
1024 the below syntax is that it allows for dynamic control via the
1025 <a href="mod_proxy_balancer.html#balancer_manager">Balancer Manager</a> interface:</p>
1027 <pre class="prettyprint lang-config">ProxyPass /mirror/foo/ http://backend.example.com/</pre>
1030 <div class="warning">
1031 <p>If the first argument ends with a trailing <strong>/</strong>, the second
1032 argument should also end with a trailing <strong>/</strong> and vice
1033 versa. Otherwise the resulting requests to the backend may miss some
1034 needed slashes and do not deliver the expected results.
1038 <p>The <code>!</code> directive is useful in situations where you don't want
1039 to reverse-proxy a subdirectory, <em>e.g.</em></p>
1041 <pre class="prettyprint lang-config"><Location /mirror/foo/>
1042 ProxyPass http://backend.example.com/
1044 <Location /mirror/foo/i>
1046 </Location></pre>
1049 <pre class="prettyprint lang-config">ProxyPass /mirror/foo/i !
1050 ProxyPass /mirror/foo http://backend.example.com</pre>
1053 <p>will proxy all requests to <code>/mirror/foo</code> to
1054 <code>backend.example.com</code> <em>except</em> requests made to
1055 <code>/mirror/foo/i</code>.</p>
1057 <div class="warning"><h3>Ordering ProxyPass Directives</h3>
1058 <p>The configured <code class="directive"><a href="#proxypass">ProxyPass</a></code>
1059 and <code class="directive"><a href="#proxypassmatch">ProxyPassMatch</a></code>
1060 rules are checked in the order of configuration. The first rule that
1061 matches wins. So usually you should sort conflicting
1062 <code class="directive"><a href="#proxypass">ProxyPass</a></code> rules starting with the
1063 longest URLs first. Otherwise later rules for longer URLS will be hidden
1064 by any earlier rule which uses a leading substring of the URL. Note that
1065 there is some relation with worker sharing. In contrast, only one
1066 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive can be placed
1067 in a <code class="directive"><a href="../mod/core.html#location">Location</a></code> block, and the most
1068 specific location will take precedence.</p>
1070 <p>For the same reasons exclusions must come <em>before</em> the
1071 general <code class="directive">ProxyPass</code> directives.</p>
1075 <p>In Apache HTTP Server 2.1 and later, mod_proxy supports pooled
1076 connections to a backend server. Connections created on demand
1077 can be retained in a pool for future use. Limits on the pool size
1078 and other settings can be coded on
1079 the <code class="directive">ProxyPass</code> directive
1080 using <code>key=value</code> parameters, described in the table
1083 <p>By default, mod_proxy will allow and retain the maximum number of
1084 connections that could be used simultaneously by that web server child
1085 process. Use the <code>max</code> parameter to reduce the number from
1086 the default. Use the <code>ttl</code> parameter to set an optional
1087 time to live; connections which have been unused for at least
1088 <code>ttl</code> seconds will be closed. <code>ttl</code> can be used
1089 to avoid using a connection which is subject to closing because of the
1090 backend server's keep-alive timeout.</p>
1092 <p>The pool of connections is maintained per web server child
1093 process, and <code>max</code> and other settings are not coordinated
1094 among all child processes, except when only one child process is allowed
1095 by configuration or MPM design.</p>
1097 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">ProxyPass /example http://backend.example.com max=20 ttl=120 retry=300</pre>
1100 <table class="bordered"><tr><th>BalancerMember parameters</th></tr></table>
1102 <tr><th>Parameter</th>
1104 <th>Description</th></tr>
1107 <td>Minimum number of connection pool entries, unrelated to the
1108 actual number of connections. This only needs to be modified from the
1109 default for special circumstances where heap memory associated with the
1110 backend connections should be preallocated or retained.</td></tr>
1113 <td>Maximum number of connections that will be allowed to the
1114 backend server. The default for this limit is the number of threads
1115 per process in the active MPM. In the Prefork MPM, this is always 1,
1116 while with other MPMs it is controlled by the
1117 <code class="directive">ThreadsPerChild</code> directive.</td></tr>
1120 <td>Retained connection pool entries above this limit are freed
1121 during certain operations if they have been unused for longer than
1122 the time to live, controlled by the <code>ttl</code> parameter. If
1123 the connection pool entry has an associated connection, it will be
1124 closed. This only needs to be modified from the default for special
1125 circumstances where connection pool entries and any associated
1126 connections which have exceeded the time to live need to be freed or
1127 closed more aggressively.</td></tr>
1128 <tr><td>acquire</td>
1130 <td>If set this will be the maximum time to wait for a free
1131 connection in the connection pool, in milliseconds. If there are no free
1132 connections in the pool the Apache httpd will return <code>SERVER_BUSY</code>
1133 status to the client.
1135 <tr><td>connectiontimeout</td>
1137 <td>Connect timeout in seconds.
1138 The number of seconds Apache httpd waits for the creation of a connection to
1139 the backend to complete. By adding a postfix of ms the timeout can be
1140 also set in milliseconds.
1142 <tr><td>disablereuse</td>
1144 <td>This parameter should be used when you want to force mod_proxy
1145 to immediately close a connection to the backend after being used, and
1146 thus, disable its persistent connection and pool for that backend.
1147 This helps in various situations where a firewall between Apache
1149 the backend server (regardless of protocol) tends to silently
1150 drop connections or when backends themselves may be under round-
1151 robin DNS. To disable connection pooling reuse,
1152 set this property value to <code>On</code>.
1154 <tr><td>flushpackets</td>
1156 <td>Determines whether the proxy module will auto-flush the output
1157 brigade after each "chunk" of data. 'off' means that it will flush
1158 only when needed, 'on' means after each chunk is sent and
1159 'auto' means poll/wait for a period of time and flush if
1160 no input has been received for 'flushwait' milliseconds.
1161 Currently this is in effect only for AJP.
1163 <tr><td>flushwait</td>
1165 <td>The time to wait for additional input, in milliseconds, before
1166 flushing the output brigade if 'flushpackets' is 'auto'.
1168 <tr><td>iobuffersize</td>
1170 <td>Adjusts the size of the internal scratchpad IO buffer. This allows you
1171 to override the <code class="directive">ProxyIOBufferSize</code> for a specific worker.
1172 This must be at least 512 or set to 0 for the system default of 8192.
1174 <tr><td>keepalive</td>
1176 <td><p>This parameter should be used when you have a firewall between your
1177 Apache httpd and the backend server, who tend to drop inactive connections.
1178 This flag will tell the Operating System to send <code>KEEP_ALIVE</code>
1179 messages on inactive connections and thus prevent the firewall to drop the connection.
1180 To enable keepalive set this property value to <code>On</code>. </p>
1181 <p>The frequency of initial and subsequent TCP keepalive probes
1182 depends on global OS settings, and may be as high as 2 hours. To be useful,
1183 the frequency configured in the OS must be smaller than the threshold used
1184 by the firewall.</p>
1188 <td>Sets the load balancer cluster set that the worker is a member
1189 of. The load balancer will try all members of a lower numbered
1190 lbset before trying higher numbered ones.
1194 <td>Ping property tells the webserver to "test" the connection to
1195 the backend before forwarding the request. For negative values
1196 the test is a simple socket check, for positive values it's
1197 a more functional check, dependent upon the protocol. For AJP, it causes
1198 <code class="module"><a href="../mod/mod_proxy_ajp.html">mod_proxy_ajp</a></code>to send a <code>CPING</code>
1199 request on the ajp13 connection (implemented on Tomcat 3.3.2+, 4.1.28+
1200 and 5.0.13+). For HTTP, it causes <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code>
1201 to send a <code>100-Continue</code> to the backend (only valid for
1202 HTTP/1.1 - for non HTTP/1.1 backends, this property has no
1203 effect). In both cases the parameter is the delay in seconds to wait
1205 This feature has been added to avoid problems with hung and
1207 This will increase the network traffic during the normal operation
1208 which could be an issue, but it will lower the
1209 traffic in case some of the cluster nodes are down or busy.
1210 By adding a postfix of ms the delay can be also set in
1213 <tr><td>receivebuffersize</td>
1215 <td>Adjusts the size of the explicit (TCP/IP) network buffer size for
1216 proxied connections. This allows you to override the
1217 <code class="directive">ProxyReceiveBufferSize</code> for a specific worker.
1218 This must be at least 512 or set to 0 for the system default.
1220 <tr><td>redirect</td>
1222 <td>Redirection Route of the worker. This value is usually
1223 set dynamically to enable safe removal of the node from
1224 the cluster. If set all requests without session id will be
1225 redirected to the BalancerMember that has route parameter
1226 equal as this value.
1230 <td>Connection pool worker retry timeout in seconds.
1231 If the connection pool worker to the backend server is in the error state,
1232 Apache httpd will not forward any requests to that server until the timeout
1233 expires. This enables to shut down the backend server for maintenance,
1234 and bring it back online later. A value of 0 means always retry workers
1235 in an error state with no timeout.
1239 <td>Route of the worker when used inside load balancer.
1240 The route is a value appended to session id.
1244 <td>Single letter value defining the initial status of
1247 <tr><td>D: Worker is disabled and will not accept any requests.</td></tr>
1248 <tr><td>S: Worker is administratively stopped.</td></tr>
1249 <tr><td>I: Worker is in ignore-errors mode, and will always be considered available.</td></tr>
1250 <tr><td>H: Worker is in hot-standby mode and will only be used if no other
1251 viable workers are available.</td></tr>
1252 <tr><td>E: Worker is in an error state.</td></tr>
1253 <tr><td>N: Worker is in drain mode, and will only accept existing sticky sessions
1254 destined for itself and ignore all other requests.</td></tr>
1256 can be set (which is the default) by prepending with '+' or
1257 cleared by prepending with '-'.
1258 Thus, a setting of 'S-E' sets this worker to Stopped and
1259 clears the in-error flag.
1261 <tr><td>timeout</td>
1262 <td><code class="directive"><a href="#proxytimeout">ProxyTimeout</a></code></td>
1263 <td>Connection timeout in seconds.
1264 The number of seconds Apache httpd waits for data sent by / to the backend.
1268 <td>Time to live for inactive connections and associated connection
1269 pool entries, in seconds. Once reaching this limit, a
1270 connection will not be used again; it will be closed at some
1276 <p>If the Proxy directive scheme starts with the
1277 <code>balancer://</code> (eg: <code>balancer://cluster</code>,
1278 any path information is ignored) then a virtual worker that does not really
1279 communicate with the backend server will be created. Instead it is responsible
1280 for the management of several "real" workers. In that case the special set of
1281 parameters can be add to this virtual worker. See <code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code>
1282 for more information about how the balancer works.
1284 <table class="bordered"><tr><th>Balancer parameters</th></tr></table>
1286 <tr><th>Parameter</th>
1288 <th>Description</th></tr>
1289 <tr><td>lbmethod</td>
1291 <td>Balancer load-balance method. Select the load-balancing scheduler
1292 method to use. Either <code>byrequests</code>, to perform weighted
1293 request counting, <code>bytraffic</code>, to perform weighted
1294 traffic byte count balancing, or <code>bybusyness</code>, to perform
1295 pending request balancing. Default is <code>byrequests</code>.
1297 <tr><td>maxattempts</td>
1298 <td>One less than the number of workers, or 1 with a single worker.</td>
1299 <td>Maximum number of failover attempts before giving up.
1301 <tr><td>nofailover</td>
1303 <td>If set to <code>On</code> the session will break if the worker is in
1304 error state or disabled. Set this value to On if backend servers do not
1305 support session replication.
1307 <tr><td>stickysession</td>
1309 <td>Balancer sticky session name. The value is usually set to something
1310 like <code>JSESSIONID</code> or <code>PHPSESSIONID</code>,
1311 and it depends on the backend application server that support sessions.
1312 If the backend application server uses different name for cookies
1313 and url encoded id (like servlet containers) use | to to separate them.
1314 The first part is for the cookie the second for the path.<br />
1315 Available in Apache HTTP Server 2.4.4 and later.
1317 <tr><td>stickysessionsep</td>
1319 <td>Sets the separation symbol in the session cookie. Some backend application servers
1320 do not use the '.' as the symbol. For example the Oracle Weblogic server uses
1321 '!'. The correct symbol can be set using this option. The setting of 'Off'
1322 signifies that no symbol is used.
1324 <tr><td>scolonpathdelim</td>
1326 <td>If set to <code>On</code> the semi-colon character ';' will be
1327 used as an additional sticky session path delimiter/separator. This
1328 is mainly used to emulate mod_jk's behavior when dealing with paths such
1329 as <code>JSESSIONID=6736bcf34;foo=aabfa</code>
1331 <tr><td>timeout</td>
1333 <td>Balancer timeout in seconds. If set this will be the maximum time
1334 to wait for a free worker. Default is not to wait.
1336 <tr><td>failonstatus</td>
1338 <td>A single or comma-separated list of HTTP status codes. If set this will
1339 force the worker into error state when the backend returns any status code
1340 in the list. Worker recovery behaves the same as other worker errors.
1342 <tr><td>failontimeout</td>
1344 <td>If set, an IO read timeout after a request is sent to the backend will
1345 force the worker into error state. Worker recovery behaves the same as other
1346 worker errors.<br />
1347 Available in Apache HTTP Server 2.4.5 and later.
1350 <td><auto></td>
1351 <td>The protective nonce used in the <code>balancer-manager</code> application page.
1352 The default is to use an automatically determined UUID-based
1353 nonce, to provide for further protection for the page. If set,
1354 then the nonce is set to that value. A setting of <code>None</code>
1355 disables all nonce checking.
1356 <div class="note"><h3>Note</h3>
1357 <p>In addition to the nonce, the <code>balancer-manager</code> page
1358 should be protected via an ACL.</p>
1363 <td>Number of additional BalancerMembers to allow to be added
1364 to this balancer in addition to those defined at configuration.
1366 <tr><td>forcerecovery</td>
1368 <td>Force the immediate recovery of all workers without considering the
1369 retry parameter of the workers if all workers of a balancer are
1370 in error state. There might be cases where an already overloaded backend
1371 can get into deeper trouble if the recovery of all workers is enforced
1372 without considering the retry parameter of each worker. In this case
1373 set to <code>Off</code>.<br />
1374 Available in Apache HTTP Server 2.4.2 and later.
1378 <p>A sample balancer setup</p>
1379 <pre class="prettyprint lang-config">ProxyPass /special-area http://special.example.com smax=5 max=10
1380 ProxyPass / balancer://mycluster/ stickysession=JSESSIONID|jsessionid nofailover=On
1381 <Proxy balancer://mycluster>
1382 BalancerMember ajp://1.2.3.4:8009
1383 BalancerMember ajp://1.2.3.5:8009 loadfactor=20
1384 # Less powerful server, don't send as many requests there,
1385 BalancerMember ajp://1.2.3.6:8009 loadfactor=5
1386 </Proxy></pre>
1389 <p>Setting up a hot-standby, that will only be used if no other
1390 members are available</p>
1391 <pre class="prettyprint lang-config">ProxyPass / balancer://hotcluster/
1392 <Proxy balancer://hotcluster>
1393 BalancerMember ajp://1.2.3.4:8009 loadfactor=1
1394 BalancerMember ajp://1.2.3.5:8009 loadfactor=2
1395 # The server below is on hot standby
1396 BalancerMember ajp://1.2.3.6:8009 status=+H
1397 ProxySet lbmethod=bytraffic
1398 </Proxy></pre>
1401 <p>Normally, mod_proxy will canonicalise ProxyPassed URLs.
1402 But this may be incompatible with some backends, particularly those
1403 that make use of <var>PATH_INFO</var>. The optional <var>nocanon</var>
1404 keyword suppresses this, and passes the URL path "raw" to the
1405 backend. Note that may affect the security of your backend, as it
1406 removes the normal limited protection against URL-based attacks
1407 provided by the proxy.</p>
1409 <p>Normally, mod_proxy will include the query string when
1410 generating the <var>SCRIPT_FILENAME</var> environment variable.
1411 The optional <var>noquery</var> keyword (available in
1412 httpd 2.4.1 and later) prevents this.</p>
1414 <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
1415 directory is obtained from the <code class="directive"><a href="../mod/core.html#location"><Location></a></code>. The same will occur inside a
1416 <code class="directive"><a href="../mod/core.html#locationmatch"><LocationMatch></a></code> section,
1417 however ProxyPass does not interpret the regexp as such, so it is necessary
1418 to use <code class="directive">ProxyPassMatch</code> in this situation instead.</p>
1420 <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>
1422 <p>If you require a more flexible reverse-proxy configuration, see the
1423 <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> directive with the
1424 <code>[P]</code> flag.</p>
1426 <p>The optional <var>interpolate</var> keyword, in combination with
1427 <code class="directive">ProxyPassInterpolateEnv</code> causes the ProxyPass
1428 to interpolate environment variables, using the syntax
1429 <var>${VARNAME}</var>. Note that many of the standard CGI-derived
1430 environment variables will not exist when this interpolation happens,
1431 so you may still have to resort to <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>
1432 for complex rules. Also note that interpolation is not supported
1433 within the scheme portion of a URL. Dynamic determination of the
1434 scheme can be accomplished with <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> as in the
1435 following example.</p>
1437 <pre class="prettyprint lang-config">RewriteEngine On
1439 RewriteCond %{HTTPS} =off
1440 RewriteRule . - [E=protocol:http]
1441 RewriteCond %{HTTPS} =on
1442 RewriteRule . - [E=protocol:https]
1444 RewriteRule ^/mirror/foo/(.*) %{ENV:protocol}://backend.example.com/$1 [P]
1445 ProxyPassReverse /mirror/foo/ http://backend.example.com/
1446 ProxyPassReverse /mirror/foo/ https://backend.example.com/</pre>
1450 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1451 <div class="directive-section"><h2><a name="ProxyPassInherit" id="ProxyPassInherit">ProxyPassInherit</a> <a name="proxypassinherit" id="proxypassinherit">Directive</a></h2>
1452 <table class="directive">
1453 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Inherit ProxyPass directives defined from the main server</td></tr>
1454 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassInherit On|Off</code></td></tr>
1455 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyPassInherit On</code></td></tr>
1456 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1457 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1458 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1459 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>ProxyPassInherit is only available in Apache HTTP Server 2.4.5 and later.
1460 and later.</td></tr>
1462 <p>This directive will cause the current server/vhost to "inherit"
1463 <code class="directive"><a href="#proxypass">ProxyPass</a></code>
1464 directives defined in the main server. This can cause issues and
1465 inconsistent behavior if using the Balancer Manager for dynamic changes
1466 and so should be disabled if using that feature.</p>
1467 <p>The setting in the global server defines the default for all vhosts.</p>
1468 <p>Disabling ProxyPassInherit also disables <code class="directive"><a href="#balancerinherit">BalancerInherit</a></code>.</p>
1471 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1472 <div class="directive-section"><h2><a name="ProxyPassInterpolateEnv" id="ProxyPassInterpolateEnv">ProxyPassInterpolateEnv</a> <a name="proxypassinterpolateenv" id="proxypassinterpolateenv">Directive</a></h2>
1473 <table class="directive">
1474 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enable Environment Variable interpolation in Reverse Proxy configurations</td></tr>
1475 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassInterpolateEnv On|Off</code></td></tr>
1476 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyPassInterpolateEnv Off</code></td></tr>
1477 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1478 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1479 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1481 <p>This directive, together with the <var>interpolate</var> argument to
1482 <code class="directive">ProxyPass</code>, <code class="directive">ProxyPassReverse</code>,
1483 <code class="directive">ProxyPassReverseCookieDomain</code> and
1484 <code class="directive">ProxyPassReverseCookiePath</code>
1485 enables reverse proxies to be dynamically
1486 configured using environment variables, which may be set by
1487 another module such as <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>.
1488 It affects the <code class="directive">ProxyPass</code>,
1489 <code class="directive">ProxyPassReverse</code>,
1490 <code class="directive">ProxyPassReverseCookieDomain</code>, and
1491 <code class="directive">ProxyPassReverseCookiePath</code> directives,
1492 and causes them to substitute the value of an environment
1493 variable <code>varname</code> for the string <code>${varname}</code>
1494 in configuration directives (if the <var>interpolate</var> option is set).</p>
1495 <p>Keep this turned off (for server performance) unless you need it!</p>
1498 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1499 <div class="directive-section"><h2><a name="ProxyPassMatch" id="ProxyPassMatch">ProxyPassMatch</a> <a name="proxypassmatch" id="proxypassmatch">Directive</a></h2>
1500 <table class="directive">
1501 <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>
1502 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassMatch [<var>regex</var>] !|<var>url</var> [<var>key=value</var>
1503 <var>[key=value</var> ...]]</code></td></tr>
1504 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1505 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1506 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1508 <p>This directive is equivalent to <code class="directive"><a href="#proxypass">ProxyPass</a></code>,
1509 but makes use of regular expressions, instead of simple prefix matching. The
1510 supplied regular expression is matched against the <var>url</var>, and if it
1511 matches, the server will substitute any parenthesized matches into the given
1512 string and use it as a new <var>url</var>.</p>
1514 <div class="note"><strong>Note: </strong>This directive cannot be used within a
1515 <code><Directory></code> context.</div>
1517 <p>Suppose the local server has address <code>http://example.com/</code>;
1520 <pre class="prettyprint lang-config">ProxyPassMatch ^/(.*\.gif)$ http://backend.example.com/$1</pre>
1523 <p>will cause a local request for
1524 <code>http://example.com/foo/bar.gif</code> to be internally converted
1525 into a proxy request to <code>http://backend.example.com/foo/bar.gif</code>.</p>
1526 <div class="note"><h3>Note</h3>
1527 <p>The URL argument must be parsable as a URL <em>before</em> regexp
1528 substitutions (as well as after). This limits the matches you can use.
1529 For instance, if we had used</p>
1530 <pre class="prettyprint lang-config">ProxyPassMatch ^(/.*\.gif)$ http://backend.example.com:8000$1</pre>
1532 <p>in our previous example, it would fail with a syntax error
1533 at server startup. This is a bug (PR 46665 in the ASF bugzilla),
1534 and the workaround is to reformulate the match:</p>
1535 <pre class="prettyprint lang-config">ProxyPassMatch ^/(.*\.gif)$ http://backend.example.com:8000/$1</pre>
1538 <p>The <code>!</code> directive is useful in situations where you don't want
1539 to reverse-proxy a subdirectory.</p>
1541 <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
1542 regexp is obtained from the <code class="directive"><a href="../mod/core.html#locationmatch"><LocationMatch></a></code>.</p>
1544 <p>If you require a more flexible reverse-proxy configuration, see the
1545 <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> directive with the
1546 <code>[P]</code> flag.</p>
1549 <h3>Default Substitution</h3>
1550 <p>When the URL parameter doesn't use any backreferences into the regular
1551 expression, the original URL will be appended to the URL parameter.
1555 <div class="warning">
1556 <h3>Security Warning</h3>
1557 <p>Take care when constructing the target URL of the rule, considering
1558 the security impact from allowing the client influence over the set of
1559 URLs to which your server will act as a proxy. Ensure that the scheme
1560 and hostname part of the URL is either fixed, or does not allow the
1561 client undue influence.</p>
1565 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1566 <div class="directive-section"><h2><a name="ProxyPassReverse" id="ProxyPassReverse">ProxyPassReverse</a> <a name="proxypassreverse" id="proxypassreverse">Directive</a></h2>
1567 <table class="directive">
1568 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Adjusts the URL in HTTP response headers sent from a reverse
1569 proxied server</td></tr>
1570 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassReverse [<var>path</var>] <var>url</var>
1571 [<var>interpolate</var>]</code></td></tr>
1572 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1573 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1574 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1576 <p>This directive lets Apache httpd adjust the URL in the <code>Location</code>,
1577 <code>Content-Location</code> and <code>URI</code> headers on HTTP
1578 redirect responses. This is essential when Apache httpd is used as a
1579 reverse proxy (or gateway) to avoid by-passing the reverse proxy
1580 because of HTTP redirects on the backend servers which stay behind
1581 the reverse proxy.</p>
1583 <p>Only the HTTP response headers specifically mentioned above
1584 will be rewritten. Apache httpd will not rewrite other response
1585 headers, nor will it by default rewrite URL references inside HTML pages.
1586 This means that if the proxied content contains absolute URL
1587 references, they will by-pass the proxy. To rewrite HTML content to
1588 match the proxy, you must load and enable <code class="module"><a href="../mod/mod_proxy_html.html">mod_proxy_html</a></code>.
1591 <p><var>path</var> is the name of a local virtual path. <var>url</var> is a
1592 partial URL for the remote server - the same way they are used for the
1593 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.</p>
1595 <p>For example, suppose the local server has address
1596 <code>http://example.com/</code>; then</p>
1598 <pre class="prettyprint lang-config">ProxyPass /mirror/foo/ http://backend.example.com/
1599 ProxyPassReverse /mirror/foo/ http://backend.example.com/
1600 ProxyPassReverseCookieDomain backend.example.com public.example.com
1601 ProxyPassReverseCookiePath / /mirror/foo/</pre>
1604 <p>will not only cause a local request for the
1605 <code>http://example.com/mirror/foo/bar</code> to be internally converted
1606 into a proxy request to <code>http://backend.example.com/bar</code>
1607 (the functionality <code>ProxyPass</code> provides here). It also takes care
1608 of redirects the server <code>backend.example.com</code> sends: when
1609 <code>http://backend.example.com/bar</code> is redirected by him to
1610 <code>http://backend.example.com/quux</code> Apache httpd adjusts this to
1611 <code>http://example.com/mirror/foo/quux</code> before forwarding the HTTP
1612 redirect response to the client. Note that the hostname used for
1613 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>
1615 <p>Note that this <code class="directive">ProxyPassReverse</code> directive can
1616 also be used in conjunction with the proxy pass-through feature
1617 (<code>RewriteRule ... [P]</code>) from <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>
1618 because it doesn't depend on a corresponding <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.</p>
1620 <p>The optional <var>interpolate</var> keyword, used together with
1621 <code class="directive">ProxyPassInterpolateEnv</code>, enables interpolation
1622 of environment variables specified using the format <var>${VARNAME}</var>.
1623 Note that interpolation is not supported within the scheme portion of a
1626 <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
1627 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
1628 intended, as ProxyPassReverse will interpret the regexp literally as a
1629 path; if needed in this situation, specify the ProxyPassReverse outside
1630 the section, or in a separate <code class="directive"><a href="../mod/core.html#location"><Location></a></code> section.</p>
1632 <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>
1635 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1636 <div class="directive-section"><h2><a name="ProxyPassReverseCookieDomain" id="ProxyPassReverseCookieDomain">ProxyPassReverseCookieDomain</a> <a name="proxypassreversecookiedomain" id="proxypassreversecookiedomain">Directive</a></h2>
1637 <table class="directive">
1638 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Adjusts the Domain string in Set-Cookie headers from a reverse-
1639 proxied server</td></tr>
1640 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassReverseCookieDomain <var>internal-domain</var>
1641 <var>public-domain</var> [<var>interpolate</var>]</code></td></tr>
1642 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1643 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1644 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1646 <p>Usage is basically similar to
1647 <code class="directive"><a href="#proxypassreverse">ProxyPassReverse</a></code>, but instead of
1648 rewriting headers that are a URL, this rewrites the <code>domain</code>
1649 string in <code>Set-Cookie</code> headers.</p>
1652 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1653 <div class="directive-section"><h2><a name="ProxyPassReverseCookiePath" id="ProxyPassReverseCookiePath">ProxyPassReverseCookiePath</a> <a name="proxypassreversecookiepath" id="proxypassreversecookiepath">Directive</a></h2>
1654 <table class="directive">
1655 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Adjusts the Path string in Set-Cookie headers from a reverse-
1656 proxied server</td></tr>
1657 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassReverseCookiePath <var>internal-path</var>
1658 <var>public-path</var> [<var>interpolate</var>]</code></td></tr>
1659 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1660 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1661 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1664 Useful in conjunction with
1665 <code class="directive"><a href="#proxypassreverse">ProxyPassReverse</a></code>
1666 in situations where backend URL paths are mapped to public paths on the
1667 reverse proxy. This directive rewrites the <code>path</code> string in
1668 <code>Set-Cookie</code> headers. If the beginning of the cookie path matches
1669 <var>internal-path</var>, the cookie path will be replaced with
1670 <var>public-path</var>.
1672 In the example given with
1673 <code class="directive"><a href="#proxypassreverse">ProxyPassReverse</a></code>, the directive:
1675 <pre class="prettyprint lang-config">ProxyPassReverseCookiePath / /mirror/foo/</pre>
1678 will rewrite a cookie with backend path <code>/</code> (or
1679 <code>/example</code> or, in fact, anything) to <code>/mirror/foo/</code>.
1683 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1684 <div class="directive-section"><h2><a name="ProxyPreserveHost" id="ProxyPreserveHost">ProxyPreserveHost</a> <a name="proxypreservehost" id="proxypreservehost">Directive</a></h2>
1685 <table class="directive">
1686 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Use incoming Host HTTP request header for proxy
1688 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPreserveHost On|Off</code></td></tr>
1689 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyPreserveHost Off</code></td></tr>
1690 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1691 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1692 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1693 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Usable in directory
1694 context in 2.3.3 and later.</td></tr>
1696 <p>When enabled, this option will pass the Host: line from the incoming
1697 request to the proxied host, instead of the hostname specified in the
1698 <code class="directive">ProxyPass</code> line.</p>
1700 <p>This option should normally be turned <code>Off</code>. It is mostly
1701 useful in special configurations like proxied mass name-based virtual
1702 hosting, where the original Host header needs to be evaluated by the
1706 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1707 <div class="directive-section"><h2><a name="ProxyReceiveBufferSize" id="ProxyReceiveBufferSize">ProxyReceiveBufferSize</a> <a name="proxyreceivebuffersize" id="proxyreceivebuffersize">Directive</a></h2>
1708 <table class="directive">
1709 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Network buffer size for proxied HTTP and FTP
1710 connections</td></tr>
1711 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyReceiveBufferSize <var>bytes</var></code></td></tr>
1712 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyReceiveBufferSize 0</code></td></tr>
1713 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1714 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1715 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1717 <p>The <code class="directive">ProxyReceiveBufferSize</code> directive specifies an
1718 explicit (TCP/IP) network buffer size for proxied HTTP and FTP connections,
1719 for increased throughput. It has to be greater than <code>512</code> or set
1720 to <code>0</code> to indicate that the system's default buffer size should
1723 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">ProxyReceiveBufferSize 2048</pre>
1727 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1728 <div class="directive-section"><h2><a name="ProxyRemote" id="ProxyRemote">ProxyRemote</a> <a name="proxyremote" id="proxyremote">Directive</a></h2>
1729 <table class="directive">
1730 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Remote proxy used to handle certain requests</td></tr>
1731 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyRemote <var>match</var> <var>remote-server</var></code></td></tr>
1732 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1733 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1734 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1736 <p>This defines remote proxies to this proxy. <var>match</var> is either the
1737 name of a URL-scheme that the remote server supports, or a partial URL
1738 for which the remote server should be used, or <code>*</code> to indicate
1739 the server should be contacted for all requests. <var>remote-server</var> is
1740 a partial URL for the remote server. Syntax:</p>
1742 <div class="example"><p><code>
1743 <dfn>remote-server</dfn> =
1744 <var>scheme</var>://<var>hostname</var>[:<var>port</var>]
1747 <p><var>scheme</var> is effectively the protocol that should be used to
1748 communicate with the remote server; only <code>http</code> and <code>https</code>
1749 are supported by this module. When using <code>https</code>, the requests
1750 are forwarded through the remote proxy using the HTTP CONNECT method.</p>
1752 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">ProxyRemote http://goodguys.example.com/ http://mirrorguys.example.com:8000
1753 ProxyRemote * http://cleverproxy.localdomain
1754 ProxyRemote ftp http://ftpproxy.mydomain:8080</pre>
1757 <p>In the last example, the proxy will forward FTP requests, encapsulated
1758 as yet another HTTP proxy request, to another proxy which can handle
1761 <p>This option also supports reverse proxy configuration - a backend
1762 webserver can be embedded within a virtualhost URL space even if that
1763 server is hidden by another forward proxy.</p>
1766 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1767 <div class="directive-section"><h2><a name="ProxyRemoteMatch" id="ProxyRemoteMatch">ProxyRemoteMatch</a> <a name="proxyremotematch" id="proxyremotematch">Directive</a></h2>
1768 <table class="directive">
1769 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Remote proxy used to handle requests matched by regular
1770 expressions</td></tr>
1771 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyRemoteMatch <var>regex</var> <var>remote-server</var></code></td></tr>
1772 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1773 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1774 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1776 <p>The <code class="directive">ProxyRemoteMatch</code> is identical to the
1777 <code class="directive"><a href="#proxyremote">ProxyRemote</a></code> directive, except the
1778 first argument is a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>
1779 match against the requested URL.</p>
1782 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1783 <div class="directive-section"><h2><a name="ProxyRequests" id="ProxyRequests">ProxyRequests</a> <a name="proxyrequests" id="proxyrequests">Directive</a></h2>
1784 <table class="directive">
1785 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables forward (standard) proxy requests</td></tr>
1786 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyRequests On|Off</code></td></tr>
1787 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyRequests Off</code></td></tr>
1788 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1789 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1790 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1792 <p>This allows or prevents Apache httpd from functioning as a forward proxy
1793 server. (Setting ProxyRequests to <code>Off</code> does not disable use of
1794 the <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.)</p>
1796 <p>In a typical reverse proxy or gateway configuration, this
1797 option should be set to
1798 <code>Off</code>.</p>
1800 <p>In order to get the functionality of proxying HTTP or FTP sites, you
1801 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>
1802 (or both) present in the server.</p>
1804 <p>In order to get the functionality of (forward) proxying HTTPS sites, you
1805 need <code class="module"><a href="../mod/mod_proxy_connect.html">mod_proxy_connect</a></code> enabled in the server.</p>
1807 <div class="warning"><h3>Warning</h3>
1808 <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
1809 both to your network and to the Internet at large.</p>
1814 <li><a href="#forwardreverse">Forward and Reverse Proxies/Gateways</a></li>
1817 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1818 <div class="directive-section"><h2><a name="ProxySet" id="ProxySet">ProxySet</a> <a name="proxyset" id="proxyset">Directive</a></h2>
1819 <table class="directive">
1820 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Set various Proxy balancer or member parameters</td></tr>
1821 <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>
1822 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
1823 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1824 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1826 <p>This directive is used as an alternate method of setting any of the
1827 parameters available to Proxy balancers and workers normally done via the
1828 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive. If used
1829 within a <code><Proxy <var>balancer url|worker url</var>></code>
1830 container directive, the <var>url</var> argument is not required. As a side
1831 effect the respective balancer or worker gets created. This can be useful
1832 when doing reverse proxying via a
1833 <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> instead of a
1834 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.</p>
1836 <div class="example"><pre class="prettyprint lang-config"><Proxy balancer://hotcluster>
1837 BalancerMember http://www2.example.com:8080 loadfactor=1
1838 BalancerMember http://www3.example.com:8080 loadfactor=2
1839 ProxySet lbmethod=bytraffic
1840 </Proxy></pre>
1843 <pre class="prettyprint lang-config"><Proxy http://backend>
1844 ProxySet keepalive=On
1845 </Proxy></pre>
1848 <pre class="prettyprint lang-config">ProxySet balancer://foo lbmethod=bytraffic timeout=15</pre>
1851 <pre class="prettyprint lang-config">ProxySet ajp://backend:7001 timeout=15</pre>
1854 <div class="warning"><h3>Warning</h3>
1855 <p>Keep in mind that the same parameter key can have a different meaning
1856 depending whether it is applied to a balancer or a worker as shown by the two
1857 examples above regarding timeout.</p>
1862 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1863 <div class="directive-section"><h2><a name="ProxySourceAddress" id="ProxySourceAddress">ProxySourceAddress</a> <a name="proxysourceaddress" id="proxysourceaddress">Directive</a></h2>
1864 <table class="directive">
1865 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Set local IP address for outgoing proxy connections</td></tr>
1866 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxySourceAddress <var>address</var></code></td></tr>
1867 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1868 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1869 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1870 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in version 2.3.9 and later</td></tr>
1872 <p>This directive allows to set a specific local address to bind to when connecting
1873 to a backend server.</p>
1876 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1877 <div class="directive-section"><h2><a name="ProxyStatus" id="ProxyStatus">ProxyStatus</a> <a name="proxystatus" id="proxystatus">Directive</a></h2>
1878 <table class="directive">
1879 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Show Proxy LoadBalancer status in mod_status</td></tr>
1880 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyStatus Off|On|Full</code></td></tr>
1881 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyStatus Off</code></td></tr>
1882 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1883 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1884 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1886 <p>This directive determines whether or not proxy
1887 loadbalancer status data is displayed via the <code class="module"><a href="../mod/mod_status.html">mod_status</a></code>
1888 server-status page.</p>
1889 <div class="note"><h3>Note</h3>
1890 <p><strong>Full</strong> is synonymous with <strong>On</strong></p>
1895 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1896 <div class="directive-section"><h2><a name="ProxyTimeout" id="ProxyTimeout">ProxyTimeout</a> <a name="proxytimeout" id="proxytimeout">Directive</a></h2>
1897 <table class="directive">
1898 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Network timeout for proxied requests</td></tr>
1899 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyTimeout <var>seconds</var></code></td></tr>
1900 <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>
1901 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1902 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1903 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1905 <p>This directive allows a user to specifiy a timeout on proxy requests.
1906 This is useful when you have a slow/buggy appserver which hangs, and you
1907 would rather just return a timeout and fail gracefully instead of waiting
1908 however long it takes the server to return.</p>
1911 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1912 <div class="directive-section"><h2><a name="ProxyVia" id="ProxyVia">ProxyVia</a> <a name="proxyvia" id="proxyvia">Directive</a></h2>
1913 <table class="directive">
1914 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Information provided in the <code>Via</code> HTTP response
1915 header for proxied requests</td></tr>
1916 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyVia On|Off|Full|Block</code></td></tr>
1917 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyVia Off</code></td></tr>
1918 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1919 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1920 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1922 <p>This directive controls the use of the <code>Via:</code> HTTP
1923 header by the proxy. Its intended use is to control the flow of
1924 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
1925 14.45 for an explanation of <code>Via:</code> header lines.</p>
1928 <li>If set to <code>Off</code>, which is the default, no special processing
1929 is performed. If a request or reply contains a <code>Via:</code> header,
1930 it is passed through unchanged.</li>
1932 <li>If set to <code>On</code>, each request and reply will get a
1933 <code>Via:</code> header line added for the current host.</li>
1935 <li>If set to <code>Full</code>, each generated <code>Via:</code> header
1936 line will additionally have the Apache httpd server version shown as a
1937 <code>Via:</code> comment field.</li>
1939 <li>If set to <code>Block</code>, every proxy request will have all its
1940 <code>Via:</code> header lines removed. No new <code>Via:</code> header will
1946 <div class="bottomlang">
1947 <p><span>Available Languages: </span><a href="../en/mod/mod_proxy.html" title="English"> en </a> |
1948 <a href="../fr/mod/mod_proxy.html" hreflang="fr" rel="alternate" title="Français"> fr </a> |
1949 <a href="../ja/mod/mod_proxy.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a></p>
1950 </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>
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