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19 <p class="apache">Apache HTTP Server Version 2.5</p>
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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="#workers">Workers</a></li>
127 <li><img alt="" src="../images/down.gif" /> <a href="#access">Controlling access to your proxy</a></li>
128 <li><img alt="" src="../images/down.gif" /> <a href="#startup">Slow Startup</a></li>
129 <li><img alt="" src="../images/down.gif" /> <a href="#intranet">Intranet Proxy</a></li>
130 <li><img alt="" src="../images/down.gif" /> <a href="#envsettings">Protocol Adjustments</a></li>
131 <li><img alt="" src="../images/down.gif" /> <a href="#request-bodies">Request Bodies</a></li>
132 <li><img alt="" src="../images/down.gif" /> <a href="#x-headers">Reverse Proxy Request Headers</a></li>
133 </ul><h3>See also</h3>
135 <li><code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code></li>
136 <li><code class="module"><a href="../mod/mod_proxy_ajp.html">mod_proxy_ajp</a></code></li>
137 <li><code class="module"><a href="../mod/mod_proxy_connect.html">mod_proxy_connect</a></code></li>
138 <li><code class="module"><a href="../mod/mod_proxy_fcgi.html">mod_proxy_fcgi</a></code></li>
139 <li><code class="module"><a href="../mod/mod_proxy_ftp.html">mod_proxy_ftp</a></code></li>
140 <li><code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code></li>
141 <li><code class="module"><a href="../mod/mod_proxy_scgi.html">mod_proxy_scgi</a></code></li>
142 <li><code class="module"><a href="../mod/mod_proxy_wstunnel.html">mod_proxy_wstunnel</a></code></li>
143 <li><code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code></li>
144 <li><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></li>
145 </ul><ul class="seealso"><li><a href="#comments_section">Comments</a></li></ul></div>
146 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
147 <div class="section">
148 <h2><a name="forwardreverse" id="forwardreverse">Forward Proxies and Reverse
149 Proxies/Gateways</a></h2>
150 <p>Apache HTTP Server can be configured in both a <dfn>forward</dfn> and
151 <dfn>reverse</dfn> proxy (also known as <dfn>gateway</dfn>) mode.</p>
153 <p>An ordinary <dfn>forward proxy</dfn> is an intermediate
154 server that sits between the client and the <em>origin
155 server</em>. In order to get content from the origin server,
156 the client sends a request to the proxy naming the origin server
157 as the target and the proxy then requests the content from the
158 origin server and returns it to the client. The client must be
159 specially configured to use the forward proxy to access other
162 <p>A typical usage of a forward proxy is to provide Internet
163 access to internal clients that are otherwise restricted by a
164 firewall. The forward proxy can also use caching (as provided
165 by <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code>) to reduce network usage.</p>
167 <p>The forward proxy is activated using the <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> directive. Because
168 forward proxies allow clients to access arbitrary sites through
169 your server and to hide their true origin, it is essential that
170 you <a href="#access">secure your server</a> so that only
171 authorized clients can access the proxy before activating a
174 <p>A <dfn>reverse proxy</dfn> (or <dfn>gateway</dfn>), by
175 contrast, appears to the client just like an ordinary web
176 server. No special configuration on the client is necessary.
177 The client makes ordinary requests for content in the name-space
178 of the reverse proxy. The reverse proxy then decides where to
179 send those requests, and returns the content as if it was itself
182 <p>A typical usage of a reverse proxy is to provide Internet
183 users access to a server that is behind a firewall. Reverse
184 proxies can also be used to balance load among several back-end
185 servers, or to provide caching for a slower back-end server.
186 In addition, reverse proxies can be used simply to bring
187 several servers into the same URL space.</p>
189 <p>A reverse proxy is activated using the <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive or the
190 <code>[P]</code> flag to the <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> directive. It is
191 <strong>not</strong> necessary to turn <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> on in order to
192 configure a reverse proxy.</p>
193 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
194 <div class="section">
195 <h2><a name="examples" id="examples">Basic Examples</a></h2>
197 <p>The examples below are only a very basic idea to help you
198 get started. Please read the documentation on the individual
201 <p>In addition, if you wish to have caching enabled, consult
202 the documentation from <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code>.</p>
204 <div class="example"><h3>Reverse Proxy</h3><pre class="prettyprint lang-config">
205 ProxyPass /foo http://foo.example.com/bar
206 ProxyPassReverse /foo http://foo.example.com/bar
210 <div class="example"><h3>Forward Proxy</h3><pre class="prettyprint lang-config">
215 Require host internal.example.com
219 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
220 <div class="section">
221 <h2><a name="workers" id="workers">Workers</a></h2>
222 <p>The proxy manages the configuration of origin servers and their
223 communication parameters in objects called <dfn>workers</dfn>.
224 There are two built-in workers, the default forward proxy worker and the
225 default reverse proxy worker. Additional workers can be configured
228 <p>The two default workers have a fixed configuration
229 and will be used if no other worker matches the request.
230 They do not use HTTP Keep-Alive or connection pooling.
231 The TCP connections to the origin server will instead be
232 opened and closed for each request.</p>
234 <p>Explicitly configured workers are identified by their URL.
235 They are usually created and configured using
236 <code class="directive"><a href="#proxypass">ProxyPass</a></code> or
237 <code class="directive"><a href="#proxypassmatch">ProxyPassMatch</a></code> when used
238 for a reverse proxy:</p>
240 <pre class="prettyprint lang-config">
241 ProxyPass /example http://backend.example.com connectiontimeout=5 timeout=30
245 <p>This will create a worker associated with the origin server URL
246 <code>http://backend.example.com</code> and using the given timeout
247 values. When used in a forward proxy, workers are usually defined
248 via the <code class="directive"><a href="#proxyset">ProxySet</a></code> directive:</p>
250 <pre class="prettyprint lang-config">
251 ProxySet http://backend.example.com connectiontimeout=5 timeout=30
255 <p>or alternatively using <code class="directive"><a href="#proxy">Proxy</a></code>
256 and <code class="directive"><a href="#proxyset">ProxySet</a></code>:</p>
258 <pre class="prettyprint lang-config">
259 <Proxy http://backend.example.com>
260 ProxySet connectiontimeout=5 timeout=30
265 <p>Using explicitly configured workers in the forward mode is
266 not very common, because forward proxies usually communicate with many
267 different origin servers. Creating explicit workers for some of the
268 origin servers can still be useful, if they are used very often.
269 Explicitly configured workers have no concept of forward or reverse
270 proxying by themselves. They encapsulate a common concept of
271 communication with origin servers. A worker created by
272 <code class="directive"><a href="#proxypass">ProxyPass</a></code> for use in a
273 reverse proxy will be also used for forward proxy requests whenever
274 the URL to the origin server matches the worker URL and vice versa.</p>
276 <p>The URL identifying a direct worker is the URL of its
277 origin server including any path components given:</p>
279 <pre class="prettyprint lang-config">
280 ProxyPass /examples http://backend.example.com/examples
281 ProxyPass /docs http://backend.example.com/docs
285 <p>This example defines two different workers, each using a separate
286 connection pool and configuration.</p>
288 <div class="warning"><h3>Worker Sharing</h3>
289 <p>Worker sharing happens if the worker URLs overlap, which occurs when
290 the URL of some worker is a leading substring of the URL of another
291 worker defined later in the configuration file. In the following example</p>
293 <pre class="prettyprint lang-config">
294 ProxyPass /apps http://backend.example.com/ timeout=60
295 ProxyPass /examples http://backend.example.com/examples timeout=10
299 <p>the second worker isn't actually created. Instead the first
300 worker is used. The benefit is, that there is only one connection pool,
301 so connections are more often reused. Note that all configuration attributes
302 given explicitly for the later worker will be ignored. This will be logged
303 as a warning. In the above example the resulting timeout value
304 for the URL <code>/examples</code> will be <code>60</code> instead
305 of <code>10</code>!</p>
307 <p>If you want to avoid worker sharing, sort your worker definitions
308 by URL length, starting with the longest worker URLs. If you want to maximize
309 worker sharing use the reverse sort order. See also the related warning about
310 ordering <code class="directive"><a href="#proxypass">ProxyPass</a></code> directives.</p>
314 <p>Explicitly configured workers come in two flavors:
315 <dfn>direct workers</dfn> and <dfn>(load) balancer workers</dfn>.
316 They support many important configuration attributes which are
317 described below in the <code class="directive"><a href="#proxypass">ProxyPass</a></code>
318 directive. The same attributes can also be set using
319 <code class="directive"><a href="#proxyset">ProxySet</a></code>.</p>
321 <p>The set of options available for a direct worker
322 depends on the protocol, which is specified in the origin server URL.
323 Available protocols include <code>ajp</code>, <code>fcgi</code>,
324 <code>ftp</code>, <code>http</code> and <code>scgi</code>.</p>
326 <p>Balancer workers are virtual workers that use direct workers known
327 as their members to actually handle the requests. Each balancer can
328 have multiple members. When it handles a request, it chooses a member
329 based on the configured load balancing algorithm.</p>
331 <p>A balancer worker is created if its worker URL uses
332 <code>balancer</code> as the protocol scheme.
333 The balancer URL uniquely identifies the balancer worker.
334 Members are added to a balancer using
335 <code class="directive"><a href="#balancermember">BalancerMember</a></code>.</p>
337 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
338 <div class="section">
339 <h2><a name="access" id="access">Controlling access to your proxy</a></h2>
340 <p>You can control who can access your proxy via the <code class="directive"><a href="#proxy"><Proxy></a></code> control block as in
341 the following example:</p>
343 <pre class="prettyprint lang-config">
350 <p>For more information on access control directives, see
351 <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code>.</p>
353 <p>Strictly limiting access is essential if you are using a
354 forward proxy (using the <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> directive).
355 Otherwise, your server can be used by any client to access
356 arbitrary hosts while hiding his or her true identity. This is
357 dangerous both for your network and for the Internet at large.
358 When using a reverse proxy (using the <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive with
359 <code>ProxyRequests Off</code>), access control is less
360 critical because clients can only contact the hosts that you
361 have specifically configured.</p>
363 <p><strong>See Also</strong> the <a href="mod_proxy_http.html#env">Proxy-Chain-Auth</a> environment variable.</p>
365 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
366 <div class="section">
367 <h2><a name="startup" id="startup">Slow Startup</a></h2>
368 <p>If you're using the <code class="directive"><a href="#proxyblock">ProxyBlock</a></code> directive, hostnames' IP addresses are looked up
369 and cached during startup for later match test. This may take a few
370 seconds (or more) depending on the speed with which the hostname lookups
372 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
373 <div class="section">
374 <h2><a name="intranet" id="intranet">Intranet Proxy</a></h2>
375 <p>An Apache httpd proxy server situated in an intranet needs to forward
376 external requests through the company's firewall (for this, configure
377 the <code class="directive"><a href="#proxyremote">ProxyRemote</a></code> directive
378 to forward the respective <var>scheme</var> to the firewall proxy).
379 However, when it has to
380 access resources within the intranet, it can bypass the firewall when
381 accessing hosts. The <code class="directive"><a href="#noproxy">NoProxy</a></code>
382 directive is useful for specifying which hosts belong to the intranet and
383 should be accessed directly.</p>
385 <p>Users within an intranet tend to omit the local domain name from their
386 WWW requests, thus requesting "http://somehost/" instead of
387 <code>http://somehost.example.com/</code>. Some commercial proxy servers
388 let them get away with this and simply serve the request, implying a
389 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
390 a redirect response and send the client to the correct, fully qualified,
391 server address. This is the preferred method since the user's bookmark
392 files will then contain fully qualified hosts.</p>
393 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
394 <div class="section">
395 <h2><a name="envsettings" id="envsettings">Protocol Adjustments</a></h2>
396 <p>For circumstances where <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> is sending
397 requests to an origin server that doesn't properly implement
398 keepalives or HTTP/1.1, there are two <a href="../env.html">environment variables</a> that can force the
399 request to use HTTP/1.0 with no keepalive. These are set via the
400 <code class="directive"><a href="../mod/mod_env.html#setenv">SetEnv</a></code> directive.</p>
402 <p>These are the <code>force-proxy-request-1.0</code> and
403 <code>proxy-nokeepalive</code> notes.</p>
405 <pre class="prettyprint lang-config">
406 <Location /buggyappserver/>
407 ProxyPass http://buggyappserver:7001/foo/
408 SetEnv force-proxy-request-1.0 1
409 SetEnv proxy-nokeepalive 1
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>
476 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
477 <div class="directive-section"><h2><a name="BalancerGrowth" id="BalancerGrowth">BalancerGrowth</a> <a name="balancergrowth" id="balancergrowth">Directive</a></h2>
478 <table class="directive">
479 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of additional Balancers that can be added Post-configuration</td></tr>
480 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>BalancerGrowth <var>#</var></code></td></tr>
481 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>BalancerGrowth 5</code></td></tr>
482 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
483 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
484 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
485 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>BalancerGrowth is only available in Apache HTTP Server 2.3.13
488 <p>This directive allows for growth potential in the number of
489 Balancers available for a virtualhost in addition to the
490 number pre-configured. It only takes effect if there is at
491 least 1 pre-configured Balancer.</p>
494 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
495 <div class="directive-section"><h2><a name="BalancerInherit" id="BalancerInherit">BalancerInherit</a> <a name="balancerinherit" id="balancerinherit">Directive</a></h2>
496 <table class="directive">
497 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Inherit proxy Balancers/Workers defined from the main server</td></tr>
498 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>BalancerInherit On|Off</code></td></tr>
499 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>BalancerInherit On</code></td></tr>
500 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
501 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
502 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
503 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>BalancerInherit is only available in Apache HTTP Server 2.4.4 and later.
506 <p>This directive will cause the current server/vhost to "inherit"
507 Balancers and Workers defined in the main server. This can cause issues and
508 inconsistent behavior if using the Balancer Manager for dynamic changes
509 and so should be disabled if using that feature.</p>
510 <p>The setting in the global server defines the default for all vhosts.</p>
511 <p>Disabling <code class="directive"><a href="#proxypassinherit">ProxyPassInherit</a></code> also disables BalancerInherit.</p>
514 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
515 <div class="directive-section"><h2><a name="BalancerMember" id="BalancerMember">BalancerMember</a> <a name="balancermember" id="balancermember">Directive</a></h2>
516 <table class="directive">
517 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Add a member to a load balancing group</td></tr>
518 <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>
519 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
520 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
521 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
523 <p>This directive adds a member to a load balancing group. It could be used
524 within a <code><Proxy <var>balancer://</var>...></code> container
525 directive, and can take any of the key value pair parameters available to
526 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directives.</p>
527 <p>One additional parameter is available only to <code class="directive"><a href="#balancermember">BalancerMember</a></code> directives:
528 <var>loadfactor</var>. This is the member load factor - a number between 1
529 (default) and 100, which defines the weighted load to be applied to the
530 member in question.</p>
531 <p>The balancerurl is only needed when not in <code><Proxy <var>balancer://</var>...></code>
532 container directive. It corresponds to the url of a balancer defined in
533 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.</p>
534 <p>The path component of the balancer URL in any
535 <code><Proxy <var>balancer://</var>...></code> container directive
537 <p>Trailing slashes should typically be removed from the URL of a
538 <code>BalancerMember</code>.</p>
541 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
542 <div class="directive-section"><h2><a name="BalancerPersist" id="BalancerPersist">BalancerPersist</a> <a name="balancerpersist" id="balancerpersist">Directive</a></h2>
543 <table class="directive">
544 <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>
545 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>BalancerPersist On|Off</code></td></tr>
546 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>BalancerPersist Off</code></td></tr>
547 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
548 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
549 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
550 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>BalancerPersist is only available in Apache HTTP Server 2.5.0
553 <p>This directive will cause the shared memory storage associated
554 with the balancers and balancer members to be persisted across
555 restarts. This allows these local changes to not be lost during the
556 normal restart/graceful state transitions.</p>
559 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
560 <div class="directive-section"><h2><a name="NoProxy" id="NoProxy">NoProxy</a> <a name="noproxy" id="noproxy">Directive</a></h2>
561 <table class="directive">
562 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Hosts, domains, or networks that will be connected to
564 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>NoProxy <var>host</var> [<var>host</var>] ...</code></td></tr>
565 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
566 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
567 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
569 <p>This directive is only useful for Apache httpd proxy servers within
570 intranets. The <code class="directive">NoProxy</code> directive specifies a
571 list of subnets, IP addresses, hosts and/or domains, separated by
572 spaces. A request to a host which matches one or more of these is
573 always served directly, without forwarding to the configured
574 <code class="directive"><a href="#proxyremote">ProxyRemote</a></code> proxy server(s).</p>
576 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">
577 ProxyRemote * http://firewall.example.com:81
578 NoProxy .example.com 192.168.112.0/21
582 <p>The <var>host</var> arguments to the <code class="directive">NoProxy</code>
583 directive are one of the following type list:</p>
587 <dt><var><a name="domain" id="domain">Domain</a></var></dt>
589 <p>A <dfn>Domain</dfn> is a partially qualified DNS domain name, preceded
590 by a period. It represents a list of hosts which logically belong to the
591 same DNS domain or zone (<em>i.e.</em>, the suffixes of the hostnames are
592 all ending in <var>Domain</var>).</p>
594 <div class="example"><h3>Examples</h3><p><code>
598 <p>To distinguish <var>Domain</var>s from <var><a href="#hostname">Hostname</a></var>s (both syntactically and semantically; a DNS domain can
599 have a DNS A record, too!), <var>Domain</var>s are always written with a
602 <div class="note"><h3>Note</h3>
603 <p>Domain name comparisons are done without regard to the case, and
604 <var>Domain</var>s are always assumed to be anchored in the root of the
605 DNS tree, therefore two domains <code>.ExAmple.com</code> and
606 <code>.example.com.</code> (note the trailing period) are considered
607 equal. Since a domain comparison does not involve a DNS lookup, it is much
608 more efficient than subnet comparison.</p>
612 <dt><var><a name="subnet" id="subnet">SubNet</a></var></dt>
614 <p>A <dfn>SubNet</dfn> is a partially qualified internet address in
615 numeric (dotted quad) form, optionally followed by a slash and the netmask,
616 specified as the number of significant bits in the <var>SubNet</var>. It is
617 used to represent a subnet of hosts which can be reached over a common
618 network interface. In the absence of the explicit net mask it is assumed
619 that omitted (or zero valued) trailing digits specify the mask. (In this
620 case, the netmask can only be multiples of 8 bits wide.) Examples:</p>
623 <dt><code>192.168</code> or <code>192.168.0.0</code></dt>
624 <dd>the subnet 192.168.0.0 with an implied netmask of 16 valid bits
625 (sometimes used in the netmask form <code>255.255.0.0</code>)</dd>
626 <dt><code>192.168.112.0/21</code></dt>
627 <dd>the subnet <code>192.168.112.0/21</code> with a netmask of 21
628 valid bits (also used in the form <code>255.255.248.0</code>)</dd>
631 <p>As a degenerate case, a <em>SubNet</em> with 32 valid bits is the
632 equivalent to an <var><a href="#ipaddr">IPAddr</a></var>, while a <var>SubNet</var> with zero
633 valid bits (<em>e.g.</em>, 0.0.0.0/0) is the same as the constant
634 <var>_Default_</var>, matching any IP address.</p></dd>
637 <dt><var><a name="ipaddr" id="ipaddr">IPAddr</a></var></dt>
639 <p>A <dfn>IPAddr</dfn> represents a fully qualified internet address in
640 numeric (dotted quad) form. Usually, this address represents a host, but
641 there need not necessarily be a DNS domain name connected with the
643 <div class="example"><h3>Example</h3><p><code>
647 <div class="note"><h3>Note</h3>
648 <p>An <var>IPAddr</var> does not need to be resolved by the DNS system, so
649 it can result in more effective apache performance.</p>
653 <dt><var><a name="hostname" id="hostname">Hostname</a></var></dt>
655 <p>A <dfn>Hostname</dfn> is a fully qualified DNS domain name which can
656 be resolved to one or more <var><a href="#ipaddr">IPAddrs</a></var> via the
657 DNS domain name service. It represents a logical host (in contrast to
658 <var><a href="#domain">Domain</a></var>s, see above) and must be resolvable
659 to at least one <var><a href="#ipaddr">IPAddr</a></var> (or often to a list
660 of hosts with different <var><a href="#ipaddr">IPAddr</a></var>s).</p>
662 <div class="example"><h3>Examples</h3><p><code>
663 prep.ai.example.edu<br />
667 <div class="note"><h3>Note</h3>
668 <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
669 DNS lookup can be avoided. Name resolution in Apache httpd can take a remarkable
670 deal of time when the connection to the name server uses a slow PPP
672 <p><var>Hostname</var> comparisons are done without regard to the case,
673 and <var>Hostname</var>s are always assumed to be anchored in the root
674 of the DNS tree, therefore two hosts <code>WWW.ExAmple.com</code>
675 and <code>www.example.com.</code> (note the trailing period) are
676 considered equal.</p>
682 <li><a href="../dns-caveats.html">DNS Issues</a></li>
685 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
686 <div class="directive-section"><h2><a name="Proxy" id="Proxy"><Proxy></a> <a name="proxy" id="proxy">Directive</a></h2>
687 <table class="directive">
688 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Container for directives applied to proxied resources</td></tr>
689 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Proxy <var>wildcard-url</var>> ...</Proxy></code></td></tr>
690 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
691 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
692 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
694 <p>Directives placed in <code class="directive"><Proxy></code>
695 sections apply only to matching proxied content. Shell-style wildcards are
698 <p>For example, the following will allow only hosts in
699 <code>yournetwork.example.com</code> to access content via your proxy
702 <pre class="prettyprint lang-config">
704 Require host yournetwork.example.com
709 <p>The following example will process all files in the <code>foo</code>
710 directory of <code>example.com</code> through the <code>INCLUDES</code>
711 filter when they are sent through the proxy server:</p>
713 <pre class="prettyprint lang-config">
714 <Proxy http://example.com/foo/*>
715 SetOutputFilter INCLUDES
720 <div class="note"><h3>Differences from the Location configuration section</h3>
721 <p>A backend URL matches the configuration section if it begins with the
722 the <var>wildcard-url</var> string, even if the last path segment in the
723 directive only matches a prefix of the backend URL. For example,
724 <Proxy http://example.com/foo> matches all of
725 http://example.com/foo, http://example.com/foo/bar, and
726 http://example.com/foobar. The matching of the final URL differs
727 from the behavior of the <code class="directive"><a href="../mod/core.html#location"><Location></a></code> section, which for purposes of this note
728 treats the final path component as if it ended in a slash.</p>
729 <p>For more control over the matching, see <code class="directive"><ProxyMatch></code>.</p>
735 <li><code class="directive"><a href="#proxymatch"><ProxyMatch></a></code></li>
738 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
739 <div class="directive-section"><h2><a name="ProxyAddHeaders" id="ProxyAddHeaders">ProxyAddHeaders</a> <a name="proxyaddheaders" id="proxyaddheaders">Directive</a></h2>
740 <table class="directive">
741 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Add proxy information in X-Forwarded-* headers</td></tr>
742 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyAddHeaders Off|On</code></td></tr>
743 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyAddHeaders On</code></td></tr>
744 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
745 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
746 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
747 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in version 2.3.10 and later</td></tr>
749 <p>This directive determines whether or not proxy related information should be passed to the
750 backend server through X-Forwarded-For, X-Forwarded-Host and X-Forwarded-Server HTTP headers.</p>
751 <div class="note"><h3>Effectiveness</h3>
752 <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>
756 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
757 <div class="directive-section"><h2><a name="ProxyBadHeader" id="ProxyBadHeader">ProxyBadHeader</a> <a name="proxybadheader" id="proxybadheader">Directive</a></h2>
758 <table class="directive">
759 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines how to handle bad header lines in a
761 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyBadHeader IsError|Ignore|StartBody</code></td></tr>
762 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyBadHeader IsError</code></td></tr>
763 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
764 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
765 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
767 <p>The <code class="directive">ProxyBadHeader</code> directive determines the
768 behaviour of <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> if it receives syntactically invalid
769 response header lines (<em>i.e.</em> containing no colon) from the origin
770 server. The following arguments are possible:</p>
773 <dt><code>IsError</code></dt>
774 <dd>Abort the request and end up with a 502 (Bad Gateway) response. This is
775 the default behaviour.</dd>
777 <dt><code>Ignore</code></dt>
778 <dd>Treat bad header lines as if they weren't sent.</dd>
780 <dt><code>StartBody</code></dt>
781 <dd>When receiving the first bad header line, finish reading the headers and
782 treat the remainder as body. This helps to work around buggy backend servers
783 which forget to insert an empty line between the headers and the body.</dd>
787 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
788 <div class="directive-section"><h2><a name="ProxyBlock" id="ProxyBlock">ProxyBlock</a> <a name="proxyblock" id="proxyblock">Directive</a></h2>
789 <table class="directive">
790 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Disallow proxy requests to certain hosts</td></tr>
791 <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>
792 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
793 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
794 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
796 <p>The <code class="directive">ProxyBlock</code> directive can be used to
797 block FTP or HTTP access to certain hosts via the proxy, based on
798 a full or partial hostname match, or, if applicable, an IP address
801 <p>Each of the arguments to the <code class="directive">ProxyBlock</code>
802 directive can be either <code>*</code> or a alphanumeric string.
803 At startup, the module will attempt to resolve every alphanumeric
804 string from a DNS name to a set of IP addresses, but any DNS errors
807 <p>If an asterisk "<code>*</code>" argument is specified,
808 <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> will deny access to all FTP or HTTP
811 <p>Otherwise, for any request for an HTTP or FTP resource via the
812 proxy, <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> will check the hostname of the
813 request URI against each specified string. If a partial string
814 match is found, access is denied. If no matches against hostnames
815 are found, and a remote (forward) proxy is configured using
816 <code class="directive">ProxyRemote</code> or
817 <code class="directive">ProxyRemoteMatch</code>, access is allowed. If no
818 remote (forward) proxy is configured, the IP address of the
819 hostname from the URI is compared against all resolved IP
820 addresses determined at startup. Access is denied if any match is
823 <p>Note that the DNS lookups may slow down the startup time of the
826 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">
827 ProxyBlock news.example.com auctions.example.com friends.example.com
831 <p>Note that <code>example</code> would also be sufficient to match any
834 <p>Hosts would also be matched if referenced by IP address.</p>
836 <p>Note also that</p>
838 <pre class="prettyprint lang-config">
843 <p>blocks connections to all sites.</p>
846 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
847 <div class="directive-section"><h2><a name="ProxyDomain" id="ProxyDomain">ProxyDomain</a> <a name="proxydomain" id="proxydomain">Directive</a></h2>
848 <table class="directive">
849 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Default domain name for proxied requests</td></tr>
850 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyDomain <var>Domain</var></code></td></tr>
851 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
852 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
853 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
855 <p>This directive is only useful for Apache httpd proxy servers within
856 intranets. The <code class="directive">ProxyDomain</code> directive specifies
857 the default domain which the apache proxy server will belong to. If a
858 request to a host without a domain name is encountered, a redirection
859 response to the same host with the configured <var>Domain</var> appended
860 will be generated.</p>
862 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">
863 ProxyRemote * http://firewall.example.com:81<br />
864 NoProxy .example.com 192.168.112.0/21<br />
865 ProxyDomain .example.com
870 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
871 <div class="directive-section"><h2><a name="ProxyErrorOverride" id="ProxyErrorOverride">ProxyErrorOverride</a> <a name="proxyerroroverride" id="proxyerroroverride">Directive</a></h2>
872 <table class="directive">
873 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Override error pages for proxied content</td></tr>
874 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyErrorOverride On|Off</code></td></tr>
875 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyErrorOverride Off</code></td></tr>
876 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
877 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
878 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
880 <p>This directive is useful for reverse-proxy setups, where you want to
881 have a common look and feel on the error pages seen by the end user.
882 This also allows for included files (via
883 <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>'s SSI) to get
884 the error code and act accordingly (default behavior would display
885 the error page of the proxied server, turning this on shows the SSI
888 <p>This directive does not affect the processing of informational (1xx),
889 normal success (2xx), or redirect (3xx) responses.</p>
892 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
893 <div class="directive-section"><h2><a name="ProxyIOBufferSize" id="ProxyIOBufferSize">ProxyIOBufferSize</a> <a name="proxyiobuffersize" id="proxyiobuffersize">Directive</a></h2>
894 <table class="directive">
895 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine size of internal data throughput buffer</td></tr>
896 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyIOBufferSize <var>bytes</var></code></td></tr>
897 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyIOBufferSize 8192</code></td></tr>
898 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
899 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
900 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
902 <p>The <code class="directive">ProxyIOBufferSize</code> directive adjusts the size
903 of the internal buffer, which is used as a scratchpad for the data between
904 input and output. The size must be at least <code>512</code>.</p>
906 <p>In almost every case there's no reason to change that value.</p>
908 <p>If used with AJP this directive sets the maximum AJP packet size in
909 bytes. Values larger than 65536 are set to 65536. If you change it from
910 the default, you must also change the <code>packetSize</code> attribute of
911 your AJP connector on the Tomcat side! The attribute
912 <code>packetSize</code> is only available in Tomcat <code>5.5.20+</code>
913 and <code>6.0.2+</code></p>
915 <p>Normally it is not necessary to change the maximum packet size.
916 Problems with the default value have been reported when sending
917 certificates or certificate chains.</p>
921 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
922 <div class="directive-section"><h2><a name="ProxyMatch" id="ProxyMatch"><ProxyMatch></a> <a name="proxymatch" id="proxymatch">Directive</a></h2>
923 <table class="directive">
924 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Container for directives applied to regular-expression-matched
925 proxied resources</td></tr>
926 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><ProxyMatch <var>regex</var>> ...</ProxyMatch></code></td></tr>
927 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
928 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
929 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
931 <p>The <code class="directive"><ProxyMatch></code> directive is
932 identical to the <code class="directive"><a href="#proxy"><Proxy></a></code> directive, except it matches URLs
933 using <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expressions</a>.</p>
935 <p>From 2.5.0 onwards, named groups and backreferences are captured and
936 written to the environment with the corresponding name prefixed with
937 "MATCH_" and in upper case. This allows elements of URLs to be referenced
938 from within <a href="expr.html">expressions</a> and modules like
939 <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered
940 (unnamed) backreferences are ignored. Use named groups instead.</p>
942 <pre class="prettyprint lang-config">
943 <ProxyMatch ^http://(?<sitename>[^/]+)>
944 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
951 <li><code class="directive"><a href="#proxy"><Proxy></a></code></li>
954 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
955 <div class="directive-section"><h2><a name="ProxyMaxForwards" id="ProxyMaxForwards">ProxyMaxForwards</a> <a name="proxymaxforwards" id="proxymaxforwards">Directive</a></h2>
956 <table class="directive">
957 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximium number of proxies that a request can be forwarded
959 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyMaxForwards <var>number</var></code></td></tr>
960 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyMaxForwards -1</code></td></tr>
961 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
962 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
963 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
965 <p>The <code class="directive">ProxyMaxForwards</code> directive specifies the
966 maximum number of proxies through which a request may pass, if there's no
967 <code>Max-Forwards</code> header supplied with the request. This may
968 be set to prevent infinite proxy loops, or a DoS attack.</p>
970 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">
975 <p>Note that setting <code class="directive">ProxyMaxForwards</code> is a
976 violation of the HTTP/1.1 protocol (RFC2616), which forbids a Proxy
977 setting <code>Max-Forwards</code> if the Client didn't set it.
978 Earlier Apache httpd versions would always set it. A negative
979 <code class="directive">ProxyMaxForwards</code> value, including the
980 default -1, gives you protocol-compliant behaviour, but may
981 leave you open to loops.</p>
984 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
985 <div class="directive-section"><h2><a name="ProxyPass" id="ProxyPass">ProxyPass</a> <a name="proxypass" id="proxypass">Directive</a></h2>
986 <table class="directive">
987 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maps remote servers into the local server URL-space</td></tr>
988 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPass [<var>path</var>] !|<var>url</var> [<var>key=value</var>
989 <var>[key=value</var> ...]] [nocanon] [interpolate] [noquery]</code></td></tr>
990 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
991 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
992 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
994 <p>This directive allows remote servers to be mapped into the
995 space of the local server; the local server does not act as a
996 proxy in the conventional sense, but appears to be a mirror of the
997 remote server. The local server is often called a <dfn>reverse
998 proxy</dfn> or <dfn>gateway</dfn>. The <var>path</var> is the name of
999 a local virtual path; <var>url</var> is a partial URL for the
1000 remote server and cannot include a query string.</p>
1003 <div class="note"><strong>Note: </strong>This directive cannot be used within a
1004 <code><Directory></code> context.</div>
1006 <div class="warning">The <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> directive should
1007 usually be set <strong>off</strong> when using
1008 <code class="directive">ProxyPass</code>.</div>
1010 <p>Support for using a Unix Domain Socket is available by using a url target
1011 which prepends <code>unix:/path/lis.sock|</code>. For example, to proxy
1012 HTTP and target the UDS at /home/www/socket you would use
1013 <code>unix:/home/www.socket|http://localhost/whatever/</code>. Since
1014 the socket is local, the hostname used (in this case <code>localhost</code>)
1015 is moot, but it is passed as the Host: header value of the request.</p>
1017 <div class="note"><strong>Note:</strong> The path associated with the <code>unix:</code>
1018 URL is <code class="directive">DefaultRuntimeDir</code> aware.</div>
1020 <div class="note"><strong>Note:</strong> <code class="directive">RewriteRule</code> requires
1021 the <code>[P,NE]</code> option to prevent the <code>'|'</code> character
1022 from being escaped.</div>
1024 <p>Suppose the local server has address <code>http://example.com/</code>;
1027 <pre class="prettyprint lang-config">
1028 <Location /mirror/foo/>
1029 ProxyPass http://backend.example.com/
1034 <p>will cause a local request for
1035 <code>http://example.com/mirror/foo/bar</code> to be internally converted
1036 into a proxy request to <code>http://backend.example.com/bar</code>.</p>
1038 <p>The following alternative syntax is possible, however it can carry a
1039 performance penalty when present in very large numbers. The advantage of
1040 the below syntax is that it allows for dynamic control via the
1041 <a href="mod_proxy_balancer.html#balancer_manager">Balancer Manager</a> interface:</p>
1043 <pre class="prettyprint lang-config">
1044 ProxyPass /mirror/foo/ http://backend.example.com/
1048 <div class="warning">
1049 <p>If the first argument ends with a trailing <strong>/</strong>, the second
1050 argument should also end with a trailing <strong>/</strong> and vice
1051 versa. Otherwise the resulting requests to the backend may miss some
1052 needed slashes and do not deliver the expected results.
1056 <p>The <code>!</code> directive is useful in situations where you don't want
1057 to reverse-proxy a subdirectory, <em>e.g.</em></p>
1059 <pre class="prettyprint lang-config">
1060 <Location /mirror/foo/>
1061 ProxyPass http://backend.example.com/
1063 <Location /mirror/foo/i>
1069 <pre class="prettyprint lang-config">
1070 ProxyPass /mirror/foo/i !
1071 ProxyPass /mirror/foo http://backend.example.com
1075 <p>will proxy all requests to <code>/mirror/foo</code> to
1076 <code>backend.example.com</code> <em>except</em> requests made to
1077 <code>/mirror/foo/i</code>.</p>
1079 <div class="warning"><h3>Ordering ProxyPass Directives</h3>
1080 <p>The configured <code class="directive"><a href="#proxypass">ProxyPass</a></code>
1081 and <code class="directive"><a href="#proxypassmatch">ProxyPassMatch</a></code>
1082 rules are checked in the order of configuration. The first rule that
1083 matches wins. So usually you should sort conflicting
1084 <code class="directive"><a href="#proxypass">ProxyPass</a></code> rules starting with the
1085 longest URLs first. Otherwise later rules for longer URLS will be hidden
1086 by any earlier rule which uses a leading substring of the URL. Note that
1087 there is some relation with worker sharing. In contrast, only one
1088 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive can be placed
1089 in a <code class="directive"><a href="../mod/core.html#location">Location</a></code> block, and the most
1090 specific location will take precedence.</p>
1092 <p>For the same reasons exclusions must come <em>before</em> the
1093 general <code class="directive">ProxyPass</code> directives.</p>
1097 <p>In Apache HTTP Server 2.1 and later, mod_proxy supports pooled
1098 connections to a backend server. Connections created on demand
1099 can be retained in a pool for future use. Limits on the pool size
1100 and other settings can be coded on
1101 the <code class="directive">ProxyPass</code> directive
1102 using <code>key=value</code> parameters, described in the table
1105 <p>By default, mod_proxy will allow and retain the maximum number of
1106 connections that could be used simultaneously by that web server child
1107 process. Use the <code>max</code> parameter to reduce the number from
1108 the default. Use the <code>ttl</code> parameter to set an optional
1109 time to live; connections which have been unused for at least
1110 <code>ttl</code> seconds will be closed. <code>ttl</code> can be used
1111 to avoid using a connection which is subject to closing because of the
1112 backend server's keep-alive timeout.</p>
1114 <p>The pool of connections is maintained per web server child
1115 process, and <code>max</code> and other settings are not coordinated
1116 among all child processes, except when only one child process is allowed
1117 by configuration or MPM design.</p>
1119 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">
1120 ProxyPass /example http://backend.example.com max=20 ttl=120 retry=300
1124 <table class="bordered"><tr><th>BalancerMember parameters</th></tr></table>
1126 <tr><th>Parameter</th>
1128 <th>Description</th></tr>
1131 <td>Minimum number of connection pool entries, unrelated to the
1132 actual number of connections. This only needs to be modified from the
1133 default for special circumstances where heap memory associated with the
1134 backend connections should be preallocated or retained.</td></tr>
1137 <td>Maximum number of connections that will be allowed to the
1138 backend server. The default for this limit is the number of threads
1139 per process in the active MPM. In the Prefork MPM, this is always 1,
1140 while with other MPMs it is controlled by the
1141 <code class="directive">ThreadsPerChild</code> directive.</td></tr>
1144 <td>Retained connection pool entries above this limit are freed
1145 during certain operations if they have been unused for longer than
1146 the time to live, controlled by the <code>ttl</code> parameter. If
1147 the connection pool entry has an associated connection, it will be
1148 closed. This only needs to be modified from the default for special
1149 circumstances where connection pool entries and any associated
1150 connections which have exceeded the time to live need to be freed or
1151 closed more aggressively.</td></tr>
1152 <tr><td>acquire</td>
1154 <td>If set this will be the maximum time to wait for a free
1155 connection in the connection pool, in milliseconds. If there are no free
1156 connections in the pool the Apache httpd will return <code>SERVER_BUSY</code>
1157 status to the client.
1159 <tr><td>connectiontimeout</td>
1161 <td>Connect timeout in seconds.
1162 The number of seconds Apache httpd waits for the creation of a connection to
1163 the backend to complete. By adding a postfix of ms the timeout can be
1164 also set in milliseconds.
1166 <tr><td>disablereuse</td>
1168 <td>This parameter should be used when you want to force mod_proxy
1169 to immediately close a connection to the backend after being used, and
1170 thus, disable its persistent connection and pool for that backend.
1171 This helps in various situations where a firewall between Apache
1173 the backend server (regardless of protocol) tends to silently
1174 drop connections or when backends themselves may be under round-
1175 robin DNS. To disable connection pooling reuse,
1176 set this property value to <code>On</code>.
1178 <tr><td>flushpackets</td>
1180 <td>Determines whether the proxy module will auto-flush the output
1181 brigade after each "chunk" of data. 'off' means that it will flush
1182 only when needed, 'on' means after each chunk is sent and
1183 'auto' means poll/wait for a period of time and flush if
1184 no input has been received for 'flushwait' milliseconds.
1185 Currently this is in effect only for AJP.
1187 <tr><td>flushwait</td>
1189 <td>The time to wait for additional input, in milliseconds, before
1190 flushing the output brigade if 'flushpackets' is 'auto'.
1192 <tr><td>iobuffersize</td>
1194 <td>Adjusts the size of the internal scratchpad IO buffer. This allows you
1195 to override the <code class="directive">ProxyIOBufferSize</code> for a specific worker.
1196 This must be at least 512 or set to 0 for the system default of 8192.
1198 <tr><td>keepalive</td>
1200 <td><p>This parameter should be used when you have a firewall between your
1201 Apache httpd and the backend server, who tend to drop inactive connections.
1202 This flag will tell the Operating System to send <code>KEEP_ALIVE</code>
1203 messages on inactive connections and thus prevent the firewall to drop the connection.
1204 To enable keepalive set this property value to <code>On</code>. </p>
1205 <p>The frequency of initial and subsequent TCP keepalive probes
1206 depends on global OS settings, and may be as high as 2 hours. To be useful,
1207 the frequency configured in the OS must be smaller than the threshold used
1208 by the firewall.</p>
1212 <td>Sets the load balancer cluster set that the worker is a member
1213 of. The load balancer will try all members of a lower numbered
1214 lbset before trying higher numbered ones.
1218 <td>Ping property tells the webserver to "test" the connection to
1219 the backend before forwarding the request. For negative values
1220 the test is a simple socket check, for positive values it's
1221 a more functional check, dependent upon the protocol. For AJP, it causes
1222 <code class="module"><a href="../mod/mod_proxy_ajp.html">mod_proxy_ajp</a></code>to send a <code>CPING</code>
1223 request on the ajp13 connection (implemented on Tomcat 3.3.2+, 4.1.28+
1224 and 5.0.13+). For HTTP, it causes <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code>
1225 to send a <code>100-Continue</code> to the backend (only valid for
1226 HTTP/1.1 - for non HTTP/1.1 backends, this property has no
1227 effect). In both cases the parameter is the delay in seconds to wait
1229 This feature has been added to avoid problems with hung and
1231 This will increase the network traffic during the normal operation
1232 which could be an issue, but it will lower the
1233 traffic in case some of the cluster nodes are down or busy.
1234 By adding a postfix of ms the delay can be also set in
1237 <tr><td>receivebuffersize</td>
1239 <td>Adjusts the size of the explicit (TCP/IP) network buffer size for
1240 proxied connections. This allows you to override the
1241 <code class="directive">ProxyReceiveBufferSize</code> for a specific worker.
1242 This must be at least 512 or set to 0 for the system default.
1244 <tr><td>redirect</td>
1246 <td>Redirection Route of the worker. This value is usually
1247 set dynamically to enable safe removal of the node from
1248 the cluster. If set all requests without session id will be
1249 redirected to the BalancerMember that has route parameter
1250 equal as this value.
1254 <td>Connection pool worker retry timeout in seconds.
1255 If the connection pool worker to the backend server is in the error state,
1256 Apache httpd will not forward any requests to that server until the timeout
1257 expires. This enables to shut down the backend server for maintenance,
1258 and bring it back online later. A value of 0 means always retry workers
1259 in an error state with no timeout.
1263 <td>Route of the worker when used inside load balancer.
1264 The route is a value appended to session id.
1268 <td>Single letter value defining the initial status of
1271 <tr><td>D: Worker is disabled and will not accept any requests.</td></tr>
1272 <tr><td>S: Worker is administratively stopped.</td></tr>
1273 <tr><td>I: Worker is in ignore-errors mode, and will always be considered available.</td></tr>
1274 <tr><td>H: Worker is in hot-standby mode and will only be used if no other
1275 viable workers are available.</td></tr>
1276 <tr><td>E: Worker is in an error state.</td></tr>
1277 <tr><td>N: Worker is in drain mode, and will only accept existing sticky sessions
1278 destined for itself and ignore all other requests.</td></tr>
1280 can be set (which is the default) by prepending with '+' or
1281 cleared by prepending with '-'.
1282 Thus, a setting of 'S-E' sets this worker to Stopped and
1283 clears the in-error flag.
1285 <tr><td>timeout</td>
1286 <td><code class="directive"><a href="#proxytimeout">ProxyTimeout</a></code></td>
1287 <td>Connection timeout in seconds.
1288 The number of seconds Apache httpd waits for data sent by / to the backend.
1292 <td>Time to live for inactive connections and associated connection
1293 pool entries, in seconds. Once reaching this limit, a
1294 connection will not be used again; it will be closed at some
1300 <p>If the Proxy directive scheme starts with the
1301 <code>balancer://</code> (eg: <code>balancer://cluster</code>,
1302 any path information is ignored) then a virtual worker that does not really
1303 communicate with the backend server will be created. Instead it is responsible
1304 for the management of several "real" workers. In that case the special set of
1305 parameters can be add to this virtual worker. See <code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code>
1306 for more information about how the balancer works.
1308 <table class="bordered"><tr><th>Balancer parameters</th></tr></table>
1310 <tr><th>Parameter</th>
1312 <th>Description</th></tr>
1313 <tr><td>lbmethod</td>
1315 <td>Balancer load-balance method. Select the load-balancing scheduler
1316 method to use. Either <code>byrequests</code>, to perform weighted
1317 request counting, <code>bytraffic</code>, to perform weighted
1318 traffic byte count balancing, or <code>bybusyness</code>, to perform
1319 pending request balancing. Default is <code>byrequests</code>.
1321 <tr><td>maxattempts</td>
1322 <td>One less than the number of workers, or 1 with a single worker.</td>
1323 <td>Maximum number of failover attempts before giving up.
1325 <tr><td>nofailover</td>
1327 <td>If set to <code>On</code> the session will break if the worker is in
1328 error state or disabled. Set this value to On if backend servers do not
1329 support session replication.
1331 <tr><td>stickysession</td>
1333 <td>Balancer sticky session name. The value is usually set to something
1334 like <code>JSESSIONID</code> or <code>PHPSESSIONID</code>,
1335 and it depends on the backend application server that support sessions.
1336 If the backend application server uses different name for cookies
1337 and url encoded id (like servlet containers) use | to to separate them.
1338 The first part is for the cookie the second for the path.
1340 <tr><td>stickysessionsep</td>
1342 <td>Sets the separation symbol in the session cookie. Some backend application servers
1343 do not use the '.' as the symbol. For example the Oracle Weblogic server uses
1344 '!'. The correct symbol can be set using this option. The setting of 'Off'
1345 signifies that no symbol is used.
1347 <tr><td>scolonpathdelim</td>
1349 <td>If set to <code>On</code> the semi-colon character ';' will be
1350 used as an additional sticky session path delimiter/separator. This
1351 is mainly used to emulate mod_jk's behavior when dealing with paths such
1352 as <code>JSESSIONID=6736bcf34;foo=aabfa</code>
1354 <tr><td>timeout</td>
1356 <td>Balancer timeout in seconds. If set this will be the maximum time
1357 to wait for a free worker. Default is not to wait.
1359 <tr><td>failonstatus</td>
1361 <td>A single or comma-separated list of HTTP status codes. If set this will
1362 force the worker into error state when the backend returns any status code
1363 in the list. Worker recovery behaves the same as other worker errors.
1365 <tr><td>failontimeout</td>
1367 <td>If set, an IO read timeout after a request is sent to the backend will
1368 force the worker into error state. Worker recovery behaves the same as other
1372 <td><auto></td>
1373 <td>The protective nonce used in the <code>balancer-manager</code> application page.
1374 The default is to use an automatically determined UUID-based
1375 nonce, to provide for further protection for the page. If set,
1376 then the nonce is set to that value. A setting of <code>None</code>
1377 disables all nonce checking.
1378 <div class="note"><h3>Note</h3>
1379 <p>In addition to the nonce, the <code>balancer-manager</code> page
1380 should be protected via an ACL.</p>
1385 <td>Number of additional BalancerMembers to allow to be added
1386 to this balancer in addition to those defined at configuration.
1388 <tr><td>forcerecovery</td>
1390 <td>Force the immediate recovery of all workers without considering the
1391 retry parameter of the workers if all workers of a balancer are
1392 in error state. There might be cases where an already overloaded backend
1393 can get into deeper trouble if the recovery of all workers is enforced
1394 without considering the retry parameter of each worker. In this case
1395 set to <code>Off</code>.
1399 <p>A sample balancer setup</p>
1400 <pre class="prettyprint lang-config">
1401 ProxyPass /special-area http://special.example.com smax=5 max=10
1402 ProxyPass / balancer://mycluster/ stickysession=JSESSIONID|jsessionid nofailover=On
1403 <Proxy balancer://mycluster>
1404 BalancerMember ajp://1.2.3.4:8009
1405 BalancerMember ajp://1.2.3.5:8009 loadfactor=20
1406 # Less powerful server, don't send as many requests there,
1407 BalancerMember ajp://1.2.3.6:8009 loadfactor=5
1412 <p>Setting up a hot-standby, that will only be used if no other
1413 members are available</p>
1414 <pre class="prettyprint lang-config">
1415 ProxyPass / balancer://hotcluster/
1416 <Proxy balancer://hotcluster>
1417 BalancerMember ajp://1.2.3.4:8009 loadfactor=1
1418 BalancerMember ajp://1.2.3.5:8009 loadfactor=2
1419 # The server below is on hot standby
1420 BalancerMember ajp://1.2.3.6:8009 status=+H
1421 ProxySet lbmethod=bytraffic
1426 <p>Normally, mod_proxy will canonicalise ProxyPassed URLs.
1427 But this may be incompatible with some backends, particularly those
1428 that make use of <var>PATH_INFO</var>. The optional <var>nocanon</var>
1429 keyword suppresses this, and passes the URL path "raw" to the
1430 backend. Note that may affect the security of your backend, as it
1431 removes the normal limited protection against URL-based attacks
1432 provided by the proxy.</p>
1434 <p>Normally, mod_proxy will include the query string when
1435 generating the <var>SCRIPT_FILENAME</var> environment variable.
1436 The optional <var>noquery</var> keyword (available in
1437 httpd 2.4.1 and later) prevents this.</p>
1439 <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
1440 directory is obtained from the <code class="directive"><a href="../mod/core.html#location"><Location></a></code>. The same will occur inside a
1441 <code class="directive"><a href="../mod/core.html#locationmatch"><LocationMatch></a></code> section,
1442 however ProxyPass does not interpret the regexp as such, so it is necessary
1443 to use <code class="directive">ProxyPassMatch</code> in this situation instead.</p>
1445 <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>
1447 <p>If you require a more flexible reverse-proxy configuration, see the
1448 <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> directive with the
1449 <code>[P]</code> flag.</p>
1451 <p>The optional <var>interpolate</var> keyword (available in
1452 httpd 2.2.9 and later), in combination with
1453 <code class="directive">ProxyPassInterpolateEnv</code> causes the ProxyPass
1454 to interpolate environment variables, using the syntax
1455 <var>${VARNAME}</var>. Note that many of the standard CGI-derived
1456 environment variables will not exist when this interpolation happens,
1457 so you may still have to resort to <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>
1458 for complex rules. Also note that interpolation is not supported
1459 within the scheme portion of a URL. Dynamic determination of the
1460 scheme can be accomplished with <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> as in the
1461 following example.</p>
1463 <pre class="prettyprint lang-config">
1466 RewriteCond %{HTTPS} =off
1467 RewriteRule . - [E=protocol:http]
1468 RewriteCond %{HTTPS} =on
1469 RewriteRule . - [E=protocol:https]
1471 RewriteRule ^/mirror/foo/(.*) %{ENV:protocol}://backend.example.com/$1 [P]
1472 ProxyPassReverse /mirror/foo/ http://backend.example.com/
1473 ProxyPassReverse /mirror/foo/ https://backend.example.com/
1478 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1479 <div class="directive-section"><h2><a name="ProxyPassInherit" id="ProxyPassInherit">ProxyPassInherit</a> <a name="proxypassinherit" id="proxypassinherit">Directive</a></h2>
1480 <table class="directive">
1481 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Inherit ProxyPass directives defined from the main server</td></tr>
1482 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassInherit On|Off</code></td></tr>
1483 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyPassInherit On</code></td></tr>
1484 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1485 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1486 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1487 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>ProxyPassInherit is only available in Apache HTTP Server 2.5.0 and later.
1488 and later.</td></tr>
1490 <p>This directive will cause the current server/vhost to "inherit"
1491 <code class="directive"><a href="#proxypass">ProxyPass</a></code>
1492 directives defined in the main server. This can cause issues and
1493 inconsistent behavior if using the Balancer Manager for dynamic changes
1494 and so should be disabled if using that feature.</p>
1495 <p>The setting in the global server defines the default for all vhosts.</p>
1496 <p>Disabling ProxyPassInherit also disables <code class="directive"><a href="#balancerinherit">BalancerInherit</a></code>.</p>
1499 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1500 <div class="directive-section"><h2><a name="ProxyPassInterpolateEnv" id="ProxyPassInterpolateEnv">ProxyPassInterpolateEnv</a> <a name="proxypassinterpolateenv" id="proxypassinterpolateenv">Directive</a></h2>
1501 <table class="directive">
1502 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enable Environment Variable interpolation in Reverse Proxy configurations</td></tr>
1503 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassInterpolateEnv On|Off</code></td></tr>
1504 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyPassInterpolateEnv Off</code></td></tr>
1505 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1506 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1507 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1509 <p>This directive, together with the <var>interpolate</var> argument to
1510 <code class="directive">ProxyPass</code>, <code class="directive">ProxyPassReverse</code>,
1511 <code class="directive">ProxyPassReverseCookieDomain</code> and
1512 <code class="directive">ProxyPassReverseCookiePath</code>
1513 enables reverse proxies to be dynamically
1514 configured using environment variables, which may be set by
1515 another module such as <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>.
1516 It affects the <code class="directive">ProxyPass</code>,
1517 <code class="directive">ProxyPassReverse</code>,
1518 <code class="directive">ProxyPassReverseCookieDomain</code>, and
1519 <code class="directive">ProxyPassReverseCookiePath</code> directives,
1520 and causes them to substitute the value of an environment
1521 variable <code>varname</code> for the string <code>${varname}</code>
1522 in configuration directives (if the <var>interpolate</var> option is set).</p>
1523 <p>Keep this turned off (for server performance) unless you need it!</p>
1526 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1527 <div class="directive-section"><h2><a name="ProxyPassMatch" id="ProxyPassMatch">ProxyPassMatch</a> <a name="proxypassmatch" id="proxypassmatch">Directive</a></h2>
1528 <table class="directive">
1529 <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>
1530 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassMatch [<var>regex</var>] !|<var>url</var> [<var>key=value</var>
1531 <var>[key=value</var> ...]]</code></td></tr>
1532 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1533 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1534 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1536 <p>This directive is equivalent to <code class="directive"><a href="#proxypass">ProxyPass</a></code>,
1537 but makes use of regular expressions, instead of simple prefix matching. The
1538 supplied regular expression is matched against the <var>url</var>, and if it
1539 matches, the server will substitute any parenthesized matches into the given
1540 string and use it as a new <var>url</var>.</p>
1542 <div class="note"><strong>Note: </strong>This directive cannot be used within a
1543 <code><Directory></code> context.</div>
1545 <p>Suppose the local server has address <code>http://example.com/</code>;
1548 <pre class="prettyprint lang-config">
1549 ProxyPassMatch ^(/.*\.gif)$ http://backend.example.com$1
1553 <p>will cause a local request for
1554 <code>http://example.com/foo/bar.gif</code> to be internally converted
1555 into a proxy request to <code>http://backend.example.com/foo/bar.gif</code>.</p>
1556 <div class="note"><h3>Note</h3>
1557 <p>The URL argument must be parsable as a URL <em>before</em> regexp
1558 substitutions (as well as after). This limits the matches you can use.
1559 For instance, if we had used</p>
1560 <pre class="prettyprint lang-config">
1561 ProxyPassMatch ^(/.*\.gif)$ http://backend.example.com:8000$1
1564 <p>in our previous example, it would fail with a syntax error
1565 at server startup. This is a bug (PR 46665 in the ASF bugzilla),
1566 and the workaround is to reformulate the match:</p>
1567 <pre class="prettyprint lang-config">
1568 ProxyPassMatch ^/(.*\.gif)$ http://backend.example.com:8000/$1
1572 <p>The <code>!</code> directive is useful in situations where you don't want
1573 to reverse-proxy a subdirectory.</p>
1575 <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
1576 regexp is obtained from the <code class="directive"><a href="../mod/core.html#locationmatch"><LocationMatch></a></code>.</p>
1578 <p>If you require a more flexible reverse-proxy configuration, see the
1579 <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> directive with the
1580 <code>[P]</code> flag.</p>
1582 <div class="warning">
1583 <h3>Security Warning</h3>
1584 <p>Take care when constructing the target URL of the rule, considering
1585 the security impact from allowing the client influence over the set of
1586 URLs to which your server will act as a proxy. Ensure that the scheme
1587 and hostname part of the URL is either fixed, or does not allow the
1588 client undue influence.</p>
1592 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1593 <div class="directive-section"><h2><a name="ProxyPassReverse" id="ProxyPassReverse">ProxyPassReverse</a> <a name="proxypassreverse" id="proxypassreverse">Directive</a></h2>
1594 <table class="directive">
1595 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Adjusts the URL in HTTP response headers sent from a reverse
1596 proxied server</td></tr>
1597 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassReverse [<var>path</var>] <var>url</var>
1598 [<var>interpolate</var>]</code></td></tr>
1599 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1600 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1601 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1603 <p>This directive lets Apache httpd adjust the URL in the <code>Location</code>,
1604 <code>Content-Location</code> and <code>URI</code> headers on HTTP
1605 redirect responses. This is essential when Apache httpd is used as a
1606 reverse proxy (or gateway) to avoid by-passing the reverse proxy
1607 because of HTTP redirects on the backend servers which stay behind
1608 the reverse proxy.</p>
1610 <p>Only the HTTP response headers specifically mentioned above
1611 will be rewritten. Apache httpd will not rewrite other response
1612 headers, nor will it by default rewrite URL references inside HTML pages.
1613 This means that if the proxied content contains absolute URL
1614 references, they will by-pass the proxy. To rewrite HTML content to
1615 match the proxy, you must load and enable <code class="module"><a href="../mod/mod_proxy_html.html">mod_proxy_html</a></code>.
1618 <p><var>path</var> is the name of a local virtual path. <var>url</var> is a
1619 partial URL for the remote server - the same way they are used for the
1620 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.</p>
1622 <p>For example, suppose the local server has address
1623 <code>http://example.com/</code>; then</p>
1625 <pre class="prettyprint lang-config">
1626 ProxyPass /mirror/foo/ http://backend.example.com/
1627 ProxyPassReverse /mirror/foo/ http://backend.example.com/
1628 ProxyPassReverseCookieDomain backend.example.com public.example.com
1629 ProxyPassReverseCookiePath / /mirror/foo/
1633 <p>will not only cause a local request for the
1634 <code>http://example.com/mirror/foo/bar</code> to be internally converted
1635 into a proxy request to <code>http://backend.example.com/bar</code>
1636 (the functionality <code>ProxyPass</code> provides here). It also takes care
1637 of redirects the server <code>backend.example.com</code> sends: when
1638 <code>http://backend.example.com/bar</code> is redirected by him to
1639 <code>http://backend.example.com/quux</code> Apache httpd adjusts this to
1640 <code>http://example.com/mirror/foo/quux</code> before forwarding the HTTP
1641 redirect response to the client. Note that the hostname used for
1642 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>
1644 <p>Note that this <code class="directive">ProxyPassReverse</code> directive can
1645 also be used in conjunction with the proxy pass-through feature
1646 (<code>RewriteRule ... [P]</code>) from <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>
1647 because it doesn't depend on a corresponding <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.</p>
1649 <p>The optional <var>interpolate</var> keyword (available in
1650 httpd 2.2.9 and later), used together with
1651 <code class="directive">ProxyPassInterpolateEnv</code>, enables interpolation
1652 of environment variables specified using the format <var>${VARNAME}</var>.
1653 Note that interpolation is not supported within the scheme portion of a
1656 <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
1657 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
1658 intended, as ProxyPassReverse will interpret the regexp literally as a
1659 path; if needed in this situation, specify the ProxyPassReverse outside
1660 the section, or in a separate <code class="directive"><a href="../mod/core.html#location"><Location></a></code> section.</p>
1662 <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>
1665 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1666 <div class="directive-section"><h2><a name="ProxyPassReverseCookieDomain" id="ProxyPassReverseCookieDomain">ProxyPassReverseCookieDomain</a> <a name="proxypassreversecookiedomain" id="proxypassreversecookiedomain">Directive</a></h2>
1667 <table class="directive">
1668 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Adjusts the Domain string in Set-Cookie headers from a reverse-
1669 proxied server</td></tr>
1670 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassReverseCookieDomain <var>internal-domain</var>
1671 <var>public-domain</var> [<var>interpolate</var>]</code></td></tr>
1672 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1673 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1674 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1676 <p>Usage is basically similar to
1677 <code class="directive"><a href="#proxypassreverse">ProxyPassReverse</a></code>, but instead of
1678 rewriting headers that are a URL, this rewrites the <code>domain</code>
1679 string in <code>Set-Cookie</code> headers.</p>
1682 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1683 <div class="directive-section"><h2><a name="ProxyPassReverseCookiePath" id="ProxyPassReverseCookiePath">ProxyPassReverseCookiePath</a> <a name="proxypassreversecookiepath" id="proxypassreversecookiepath">Directive</a></h2>
1684 <table class="directive">
1685 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Adjusts the Path string in Set-Cookie headers from a reverse-
1686 proxied server</td></tr>
1687 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassReverseCookiePath <var>internal-path</var>
1688 <var>public-path</var> [<var>interpolate</var>]</code></td></tr>
1689 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1690 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1691 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1694 Useful in conjunction with
1695 <code class="directive"><a href="#proxypassreverse">ProxyPassReverse</a></code>
1696 in situations where backend URL paths are mapped to public paths on the
1697 reverse proxy. This directive rewrites the <code>path</code> string in
1698 <code>Set-Cookie</code> headers. If the beginning of the cookie path matches
1699 <var>internal-path</var>, the cookie path will be replaced with
1700 <var>public-path</var>.
1702 In the example given with
1703 <code class="directive"><a href="#proxypassreverse">ProxyPassReverse</a></code>, the directive:
1705 <pre class="prettyprint lang-config">
1706 ProxyPassReverseCookiePath / /mirror/foo/
1710 will rewrite a cookie with backend path <code>/</code> (or
1711 <code>/example</code> or, in fact, anything) to <code>/mirror/foo/</code>.
1715 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1716 <div class="directive-section"><h2><a name="ProxyPreserveHost" id="ProxyPreserveHost">ProxyPreserveHost</a> <a name="proxypreservehost" id="proxypreservehost">Directive</a></h2>
1717 <table class="directive">
1718 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Use incoming Host HTTP request header for proxy
1720 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPreserveHost On|Off</code></td></tr>
1721 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyPreserveHost Off</code></td></tr>
1722 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1723 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1724 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1725 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Usable in directory
1726 context in 2.3.3 and later.</td></tr>
1728 <p>When enabled, this option will pass the Host: line from the incoming
1729 request to the proxied host, instead of the hostname specified in the
1730 <code class="directive">ProxyPass</code> line.</p>
1732 <p>This option should normally be turned <code>Off</code>. It is mostly
1733 useful in special configurations like proxied mass name-based virtual
1734 hosting, where the original Host header needs to be evaluated by the
1738 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1739 <div class="directive-section"><h2><a name="ProxyReceiveBufferSize" id="ProxyReceiveBufferSize">ProxyReceiveBufferSize</a> <a name="proxyreceivebuffersize" id="proxyreceivebuffersize">Directive</a></h2>
1740 <table class="directive">
1741 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Network buffer size for proxied HTTP and FTP
1742 connections</td></tr>
1743 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyReceiveBufferSize <var>bytes</var></code></td></tr>
1744 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyReceiveBufferSize 0</code></td></tr>
1745 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1746 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1747 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1749 <p>The <code class="directive">ProxyReceiveBufferSize</code> directive specifies an
1750 explicit (TCP/IP) network buffer size for proxied HTTP and FTP connections,
1751 for increased throughput. It has to be greater than <code>512</code> or set
1752 to <code>0</code> to indicate that the system's default buffer size should
1755 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">
1756 ProxyReceiveBufferSize 2048
1761 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1762 <div class="directive-section"><h2><a name="ProxyRemote" id="ProxyRemote">ProxyRemote</a> <a name="proxyremote" id="proxyremote">Directive</a></h2>
1763 <table class="directive">
1764 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Remote proxy used to handle certain requests</td></tr>
1765 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyRemote <var>match</var> <var>remote-server</var></code></td></tr>
1766 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1767 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1768 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1770 <p>This defines remote proxies to this proxy. <var>match</var> is either the
1771 name of a URL-scheme that the remote server supports, or a partial URL
1772 for which the remote server should be used, or <code>*</code> to indicate
1773 the server should be contacted for all requests. <var>remote-server</var> is
1774 a partial URL for the remote server. Syntax:</p>
1776 <div class="example"><p><code>
1777 <dfn>remote-server</dfn> =
1778 <var>scheme</var>://<var>hostname</var>[:<var>port</var>]
1781 <p><var>scheme</var> is effectively the protocol that should be used to
1782 communicate with the remote server; only <code>http</code> and <code>https</code>
1783 are supported by this module. When using <code>https</code>, the requests
1784 are forwarded through the remote proxy using the HTTP CONNECT method.</p>
1786 <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">
1787 ProxyRemote http://goodguys.example.com/ http://mirrorguys.example.com:8000
1788 ProxyRemote * http://cleverproxy.localdomain
1789 ProxyRemote ftp http://ftpproxy.mydomain:8080
1793 <p>In the last example, the proxy will forward FTP requests, encapsulated
1794 as yet another HTTP proxy request, to another proxy which can handle
1797 <p>This option also supports reverse proxy configuration - a backend
1798 webserver can be embedded within a virtualhost URL space even if that
1799 server is hidden by another forward proxy.</p>
1802 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1803 <div class="directive-section"><h2><a name="ProxyRemoteMatch" id="ProxyRemoteMatch">ProxyRemoteMatch</a> <a name="proxyremotematch" id="proxyremotematch">Directive</a></h2>
1804 <table class="directive">
1805 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Remote proxy used to handle requests matched by regular
1806 expressions</td></tr>
1807 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyRemoteMatch <var>regex</var> <var>remote-server</var></code></td></tr>
1808 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1809 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1810 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1812 <p>The <code class="directive">ProxyRemoteMatch</code> is identical to the
1813 <code class="directive"><a href="#proxyremote">ProxyRemote</a></code> directive, except the
1814 first argument is a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>
1815 match against the requested URL.</p>
1818 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1819 <div class="directive-section"><h2><a name="ProxyRequests" id="ProxyRequests">ProxyRequests</a> <a name="proxyrequests" id="proxyrequests">Directive</a></h2>
1820 <table class="directive">
1821 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables forward (standard) proxy requests</td></tr>
1822 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyRequests On|Off</code></td></tr>
1823 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyRequests Off</code></td></tr>
1824 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1825 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1826 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1828 <p>This allows or prevents Apache httpd from functioning as a forward proxy
1829 server. (Setting ProxyRequests to <code>Off</code> does not disable use of
1830 the <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.)</p>
1832 <p>In a typical reverse proxy or gateway configuration, this
1833 option should be set to
1834 <code>Off</code>.</p>
1836 <p>In order to get the functionality of proxying HTTP or FTP sites, you
1837 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>
1838 (or both) present in the server.</p>
1840 <p>In order to get the functionality of (forward) proxying HTTPS sites, you
1841 need <code class="module"><a href="../mod/mod_proxy_connect.html">mod_proxy_connect</a></code> enabled in the server.</p>
1843 <div class="warning"><h3>Warning</h3>
1844 <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
1845 both to your network and to the Internet at large.</p>
1850 <li><a href="#forwardreverse">Forward and Reverse Proxies/Gateways</a></li>
1853 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1854 <div class="directive-section"><h2><a name="ProxySet" id="ProxySet">ProxySet</a> <a name="proxyset" id="proxyset">Directive</a></h2>
1855 <table class="directive">
1856 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Set various Proxy balancer or member parameters</td></tr>
1857 <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>
1858 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
1859 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1860 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1862 <p>This directive is used as an alternate method of setting any of the
1863 parameters available to Proxy balancers and workers normally done via the
1864 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive. If used
1865 within a <code><Proxy <var>balancer url|worker url</var>></code>
1866 container directive, the <var>url</var> argument is not required. As a side
1867 effect the respective balancer or worker gets created. This can be useful
1868 when doing reverse proxying via a
1869 <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> instead of a
1870 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.</p>
1872 <div class="example"><pre class="prettyprint lang-config">
1873 <Proxy balancer://hotcluster>
1874 BalancerMember http://www2.example.com:8080 loadfactor=1
1875 BalancerMember http://www3.example.com:8080 loadfactor=2
1876 ProxySet lbmethod=bytraffic
1881 <pre class="prettyprint lang-config">
1882 <Proxy http://backend>
1883 ProxySet keepalive=On
1888 <pre class="prettyprint lang-config">
1889 ProxySet balancer://foo lbmethod=bytraffic timeout=15
1893 <pre class="prettyprint lang-config">
1894 ProxySet ajp://backend:7001 timeout=15
1898 <div class="warning"><h3>Warning</h3>
1899 <p>Keep in mind that the same parameter key can have a different meaning
1900 depending whether it is applied to a balancer or a worker as shown by the two
1901 examples above regarding timeout.</p>
1906 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1907 <div class="directive-section"><h2><a name="ProxySourceAddress" id="ProxySourceAddress">ProxySourceAddress</a> <a name="proxysourceaddress" id="proxysourceaddress">Directive</a></h2>
1908 <table class="directive">
1909 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Set local IP address for outgoing proxy connections</td></tr>
1910 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxySourceAddress <var>address</var></code></td></tr>
1911 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1912 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1913 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1914 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in version 2.3.9 and later</td></tr>
1916 <p>This directive allows to set a specific local address to bind to when connecting
1917 to a backend server.</p>
1920 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1921 <div class="directive-section"><h2><a name="ProxyStatus" id="ProxyStatus">ProxyStatus</a> <a name="proxystatus" id="proxystatus">Directive</a></h2>
1922 <table class="directive">
1923 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Show Proxy LoadBalancer status in mod_status</td></tr>
1924 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyStatus Off|On|Full</code></td></tr>
1925 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyStatus Off</code></td></tr>
1926 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1927 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1928 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1930 <p>This directive determines whether or not proxy
1931 loadbalancer status data is displayed via the <code class="module"><a href="../mod/mod_status.html">mod_status</a></code>
1932 server-status page.</p>
1933 <div class="note"><h3>Note</h3>
1934 <p><strong>Full</strong> is synonymous with <strong>On</strong></p>
1939 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1940 <div class="directive-section"><h2><a name="ProxyTimeout" id="ProxyTimeout">ProxyTimeout</a> <a name="proxytimeout" id="proxytimeout">Directive</a></h2>
1941 <table class="directive">
1942 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Network timeout for proxied requests</td></tr>
1943 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyTimeout <var>seconds</var></code></td></tr>
1944 <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>
1945 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1946 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1947 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1949 <p>This directive allows a user to specifiy a timeout on proxy requests.
1950 This is useful when you have a slow/buggy appserver which hangs, and you
1951 would rather just return a timeout and fail gracefully instead of waiting
1952 however long it takes the server to return.</p>
1955 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1956 <div class="directive-section"><h2><a name="ProxyVia" id="ProxyVia">ProxyVia</a> <a name="proxyvia" id="proxyvia">Directive</a></h2>
1957 <table class="directive">
1958 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Information provided in the <code>Via</code> HTTP response
1959 header for proxied requests</td></tr>
1960 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyVia On|Off|Full|Block</code></td></tr>
1961 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyVia Off</code></td></tr>
1962 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1963 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1964 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1966 <p>This directive controls the use of the <code>Via:</code> HTTP
1967 header by the proxy. Its intended use is to control the flow of
1968 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
1969 14.45 for an explanation of <code>Via:</code> header lines.</p>
1972 <li>If set to <code>Off</code>, which is the default, no special processing
1973 is performed. If a request or reply contains a <code>Via:</code> header,
1974 it is passed through unchanged.</li>
1976 <li>If set to <code>On</code>, each request and reply will get a
1977 <code>Via:</code> header line added for the current host.</li>
1979 <li>If set to <code>Full</code>, each generated <code>Via:</code> header
1980 line will additionally have the Apache httpd server version shown as a
1981 <code>Via:</code> comment field.</li>
1983 <li>If set to <code>Block</code>, every proxy request will have all its
1984 <code>Via:</code> header lines removed. No new <code>Via:</code> header will
1990 <div class="bottomlang">
1991 <p><span>Available Languages: </span><a href="../en/mod/mod_proxy.html" title="English"> en </a> |
1992 <a href="../fr/mod/mod_proxy.html" hreflang="fr" rel="alternate" title="Français"> fr </a> |
1993 <a href="../ja/mod/mod_proxy.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a></p>
1994 </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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