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23 <modulesynopsis metafile="mod_proxy.xml.meta">
25 <name>mod_proxy</name>
26 <description>Multi-protocol proxy/gateway server</description>
27 <status>Extension</status>
28 <sourcefile>mod_proxy.c</sourcefile>
29 <identifier>proxy_module</identifier>
32 <note type="warning"><title>Warning</title>
33 <p>Do not enable proxying with <directive module="mod_proxy"
34 >ProxyRequests</directive> until you have <a href="#access"
35 >secured your server</a>. Open proxy servers are dangerous both to your
36 network and to the Internet at large.</p>
39 <p><module>mod_proxy</module> and related modules implement a
40 proxy/gateway for Apache HTTP Server, supporting a number of popular
41 protocols as well as several different load balancing algorithms.
42 Third-party modules can add support for additional protocols and
43 load balancing algorithms.</p>
45 <p>A set of modules must be loaded into the server to provide the
46 necessary features. These modules can be included statically at
47 build time or dynamically via the
48 <directive module="mod_so">LoadModule</directive> directive).
49 The set must include:</p>
52 <li><module>mod_proxy</module>, which provides basic proxy
55 <li><module>mod_proxy_balancer</module> and one or more
56 balancer modules if load balancing is required. (See
57 <module>mod_proxy_balancer</module> for more information.)</li>
59 <li>one or more proxy scheme, or protocol, modules:
62 <tr><th>Protocol</th><th>Module</th></tr>
63 <tr><td>AJP13 (Apache JServe Protocol version
64 1.3)</td><td><module>mod_proxy_ajp</module></td></tr>
66 SSL)</td><td><module>mod_proxy_connect</module></td></tr>
67 <tr><td>FastCGI</td><td><module>mod_proxy_fcgi</module></td></tr>
68 <tr><td>ftp</td><td><module>mod_proxy_ftp</module></td></tr>
69 <tr><td>HTTP/0.9, HTTP/1.0, and
70 HTTP/1.1</td><td><module>mod_proxy_http</module></td></tr>
71 <tr><td>SCGI</td><td><module>mod_proxy_scgi</module></td></tr>
72 <tr><td>WS and WSS (Web-sockets)</td><td><module>mod_proxy_wstunnel</module></td></tr>
77 <p>In addition, extended features are provided by other modules.
78 Caching is provided by <module>mod_cache</module> and related
79 modules. The ability to contact remote servers using the SSL/TLS
80 protocol is provided by the <code>SSLProxy*</code> directives of
81 <module>mod_ssl</module>. These additional modules will need
82 to be loaded and configured to take advantage of these features.</p>
84 <seealso><module>mod_cache</module></seealso>
85 <seealso><module>mod_proxy_ajp</module></seealso>
86 <seealso><module>mod_proxy_balancer</module></seealso>
87 <seealso><module>mod_proxy_connect</module></seealso>
88 <seealso><module>mod_proxy_fcgi</module></seealso>
89 <seealso><module>mod_proxy_ftp</module></seealso>
90 <seealso><module>mod_proxy_hcheck</module></seealso>
91 <seealso><module>mod_proxy_http</module></seealso>
92 <seealso><module>mod_proxy_scgi</module></seealso>
93 <seealso><module>mod_proxy_wstunnel</module></seealso>
94 <seealso><module>mod_ssl</module></seealso>
96 <section id="forwardreverse"><title>Forward Proxies and Reverse
97 Proxies/Gateways</title>
98 <p>Apache HTTP Server can be configured in both a <dfn>forward</dfn> and
99 <dfn>reverse</dfn> proxy (also known as <dfn>gateway</dfn>) mode.</p>
101 <p>An ordinary <dfn>forward proxy</dfn> is an intermediate
102 server that sits between the client and the <em>origin
103 server</em>. In order to get content from the origin server,
104 the client sends a request to the proxy naming the origin server
105 as the target. The proxy then requests the content from the
106 origin server and returns it to the client. The client must be
107 specially configured to use the forward proxy to access other
110 <p>A typical usage of a forward proxy is to provide Internet
111 access to internal clients that are otherwise restricted by a
112 firewall. The forward proxy can also use caching (as provided
113 by <module>mod_cache</module>) to reduce network usage.</p>
115 <p>The forward proxy is activated using the <directive
116 module="mod_proxy">ProxyRequests</directive> directive. Because
117 forward proxies allow clients to access arbitrary sites through
118 your server and to hide their true origin, it is essential that
119 you <a href="#access">secure your server</a> so that only
120 authorized clients can access the proxy before activating a
123 <p>A <dfn>reverse proxy</dfn> (or <dfn>gateway</dfn>), by
124 contrast, appears to the client just like an ordinary web
125 server. No special configuration on the client is necessary.
126 The client makes ordinary requests for content in the namespace
127 of the reverse proxy. The reverse proxy then decides where to
128 send those requests and returns the content as if it were itself
131 <p>A typical usage of a reverse proxy is to provide Internet
132 users access to a server that is behind a firewall. Reverse
133 proxies can also be used to balance load among several back-end
134 servers or to provide caching for a slower back-end server.
135 In addition, reverse proxies can be used simply to bring
136 several servers into the same URL space.</p>
138 <p>A reverse proxy is activated using the <directive
139 module="mod_proxy">ProxyPass</directive> directive or the
140 <code>[P]</code> flag to the <directive
141 module="mod_rewrite">RewriteRule</directive> directive. It is
142 <strong>not</strong> necessary to turn <directive
143 module="mod_proxy">ProxyRequests</directive> on in order to
144 configure a reverse proxy.</p>
145 </section> <!-- /forwardreverse -->
147 <section id="examples"><title>Basic Examples</title>
149 <p>The examples below are only a very basic idea to help you
150 get started. Please read the documentation on the individual
153 <p>In addition, if you wish to have caching enabled, consult
154 the documentation from <module>mod_cache</module>.</p>
156 <example><title>Reverse Proxy</title>
157 <highlight language="config">
158 ProxyPass "/foo" "http://foo.example.com/bar"
159 ProxyPassReverse "/foo" "http://foo.example.com/bar"
163 <example><title>Forward Proxy</title>
164 <highlight language="config">
169 Require host internal.example.com
173 </section> <!-- /examples -->
175 <section id="handler"><title>Access via Handler</title>
177 <p>You can also force a request to be handled as a reverse-proxy
178 request, by creating a suitable Handler pass-through. The example
179 configuration below will pass all requests for PHP scripts to the
180 specified FastCGI server using reverse proxy:
183 <example><title>Reverse Proxy PHP scripts</title>
184 <highlight language="config">
185 <FilesMatch "\.php$">
186 SetHandler "proxy:unix:/path/to/app.sock|fcgi://localhost/"
191 <p>This feature is available in Apache HTTP Server 2.4.10 and later.</p>
193 </section> <!-- /handler -->
195 <section id="workers"><title>Workers</title>
196 <p>The proxy manages the configuration of origin servers and their
197 communication parameters in objects called <dfn>workers</dfn>.
198 There are two built-in workers: the default forward proxy worker and the
199 default reverse proxy worker. Additional workers can be configured
202 <p>The two default workers have a fixed configuration
203 and will be used if no other worker matches the request.
204 They do not use HTTP Keep-Alive or connection pooling.
205 The TCP connections to the origin server will instead be
206 opened and closed for each request.</p>
208 <p>Explicitly configured workers are identified by their URL.
209 They are usually created and configured using
210 <directive module="mod_proxy">ProxyPass</directive> or
211 <directive module="mod_proxy">ProxyPassMatch</directive> when used
212 for a reverse proxy:</p>
214 <highlight language="config">
215 ProxyPass "/example" "http://backend.example.com" connectiontimeout=5 timeout=30
218 <p>This will create a worker associated with the origin server URL
219 <code>http://backend.example.com</code> that will use the given timeout
220 values. When used in a forward proxy, workers are usually defined
221 via the <directive module="mod_proxy">ProxySet</directive> directive:</p>
223 <highlight language="config">
224 ProxySet http://backend.example.com connectiontimeout=5 timeout=30
227 <p>or alternatively using <directive module="mod_proxy">Proxy</directive>
228 and <directive module="mod_proxy">ProxySet</directive>:</p>
230 <highlight language="config">
231 <Proxy http://backend.example.com>
232 ProxySet connectiontimeout=5 timeout=30
236 <p>Using explicitly configured workers in the forward mode is
237 not very common, because forward proxies usually communicate with many
238 different origin servers. Creating explicit workers for some of the
239 origin servers can still be useful if they are used very often.
240 Explicitly configured workers have no concept of forward or reverse
241 proxying by themselves. They encapsulate a common concept of
242 communication with origin servers. A worker created by
243 <directive module="mod_proxy">ProxyPass</directive> for use in a
244 reverse proxy will also be used for forward proxy requests whenever
245 the URL to the origin server matches the worker URL, and vice versa.</p>
247 <p>The URL identifying a direct worker is the URL of its
248 origin server including any path components given:</p>
250 <highlight language="config">
251 ProxyPass "/examples" "http://backend.example.com/examples"
252 ProxyPass "/docs" "http://backend.example.com/docs"
255 <p>This example defines two different workers, each using a separate
256 connection pool and configuration.</p>
258 <note type="warning"><title>Worker Sharing</title>
259 <p>Worker sharing happens if the worker URLs overlap, which occurs when
260 the URL of some worker is a leading substring of the URL of another
261 worker defined later in the configuration file. In the following example</p>
263 <highlight language="config">
264 ProxyPass "/apps" "http://backend.example.com/" timeout=60
265 ProxyPass "/examples" "http://backend.example.com/examples" timeout=10
268 <p>the second worker isn't actually created. Instead the first
269 worker is used. The benefit is, that there is only one connection pool,
270 so connections are more often reused. Note that all configuration attributes
271 given explicitly for the later worker will be ignored. This will be logged
272 as a warning. In the above example, the resulting timeout value
273 for the URL <code>/examples</code> will be <code>60</code> instead
274 of <code>10</code>!</p>
276 <p>If you want to avoid worker sharing, sort your worker definitions
277 by URL length, starting with the longest worker URLs. If you want to maximize
278 worker sharing, use the reverse sort order. See also the related warning about
279 ordering <directive module="mod_proxy">ProxyPass</directive> directives.</p>
281 </note> <!-- /worker_sharing -->
283 <p>Explicitly configured workers come in two flavors:
284 <dfn>direct workers</dfn> and <dfn>(load) balancer workers</dfn>.
285 They support many important configuration attributes which are
286 described below in the <directive module="mod_proxy">ProxyPass</directive>
287 directive. The same attributes can also be set using
288 <directive module="mod_proxy">ProxySet</directive>.</p>
290 <p>The set of options available for a direct worker
291 depends on the protocol which is specified in the origin server URL.
292 Available protocols include <code>ajp</code>, <code>fcgi</code>,
293 <code>ftp</code>, <code>http</code> and <code>scgi</code>.</p>
295 <p>Balancer workers are virtual workers that use direct workers known
296 as their members to actually handle the requests. Each balancer can
297 have multiple members. When it handles a request, it chooses a member
298 based on the configured load balancing algorithm.</p>
300 <p>A balancer worker is created if its worker URL uses
301 <code>balancer</code> as the protocol scheme.
302 The balancer URL uniquely identifies the balancer worker.
303 Members are added to a balancer using
304 <directive module="mod_proxy">BalancerMember</directive>.</p>
306 <note><title>DNS resolution for origin domains</title>
307 <p>DNS resolution happens when the socket to
308 the origin domain is created for the first time.
309 When connection pooling is used, each backend domain is resolved
310 only once per child process, and reused for all further connections
311 until the child is recycled. This information should to be considered
312 while planning DNS maintenance tasks involving backend domains.
313 Please also check <directive module="mod_proxy">ProxyPass</directive>
314 parameters for more details about connection reuse.
318 </section> <!-- /workers -->
320 <section id="access"><title>Controlling Access to Your Proxy</title>
321 <p>You can control who can access your proxy via the <directive
322 module="mod_proxy" type="section">Proxy</directive> control block as in
323 the following example:</p>
325 <highlight language="config">
331 <p>For more information on access control directives, see
332 <module>mod_authz_host</module>.</p>
334 <p>Strictly limiting access is essential if you are using a
335 forward proxy (using the <directive
336 module="mod_proxy">ProxyRequests</directive> directive).
337 Otherwise, your server can be used by any client to access
338 arbitrary hosts while hiding his or her true identity. This is
339 dangerous both for your network and for the Internet at large.
340 When using a reverse proxy (using the <directive
341 module="mod_proxy">ProxyPass</directive> directive with
342 <code>ProxyRequests Off</code>), access control is less
343 critical because clients can only contact the hosts that you
344 have specifically configured.</p>
346 <p><strong>See Also</strong> the <a href="mod_proxy_http.html#env"
347 >Proxy-Chain-Auth</a> environment variable.</p>
349 </section> <!-- /access -->
351 <section id="startup"><title>Slow Startup</title>
352 <p>If you're using the <directive module="mod_proxy"
353 >ProxyBlock</directive> directive, hostnames' IP addresses are looked up
354 and cached during startup for later match test. This may take a few
355 seconds (or more) depending on the speed with which the hostname lookups
357 </section> <!-- /startup -->
359 <section id="intranet"><title>Intranet Proxy</title>
360 <p>An Apache httpd proxy server situated in an intranet needs to forward
361 external requests through the company's firewall (for this, configure
362 the <directive module="mod_proxy">ProxyRemote</directive> directive
363 to forward the respective <var>scheme</var> to the firewall proxy).
364 However, when it has to
365 access resources within the intranet, it can bypass the firewall when
366 accessing hosts. The <directive module="mod_proxy">NoProxy</directive>
367 directive is useful for specifying which hosts belong to the intranet and
368 should be accessed directly.</p>
370 <p>Users within an intranet tend to omit the local domain name from their
371 WWW requests, thus requesting "http://somehost/" instead of
372 <code>http://somehost.example.com/</code>. Some commercial proxy servers
373 let them get away with this and simply serve the request, implying a
374 configured local domain. When the <directive module="mod_proxy"
375 >ProxyDomain</directive> directive is used and the server is <a
376 href="#proxyrequests">configured for proxy service</a>, Apache httpd can return
377 a redirect response and send the client to the correct, fully qualified,
378 server address. This is the preferred method since the user's bookmark
379 files will then contain fully qualified hosts.</p>
380 </section> <!-- /intranet -->
382 <section id="envsettings"><title>Protocol Adjustments</title>
383 <p>For circumstances where <module>mod_proxy</module> is sending
384 requests to an origin server that doesn't properly implement
385 keepalives or HTTP/1.1, there are two <a
386 href="../env.html">environment variables</a> that can force the
387 request to use HTTP/1.0 with no keepalive. These are set via the
388 <directive module="mod_env">SetEnv</directive> directive.</p>
390 <p>These are the <code>force-proxy-request-1.0</code> and
391 <code>proxy-nokeepalive</code> notes.</p>
393 <highlight language="config">
394 <Location "/buggyappserver/">
395 ProxyPass "http://buggyappserver:7001/foo/"
396 SetEnv force-proxy-request-1.0 1
397 SetEnv proxy-nokeepalive 1
401 </section> <!-- /envsettings -->
403 <section id="request-bodies"><title>Request Bodies</title>
405 <p>Some request methods such as POST include a request body.
406 The HTTP protocol requires that requests which include a body
407 either use chunked transfer encoding or send a
408 <code>Content-Length</code> request header. When passing these
409 requests on to the origin server, <module>mod_proxy_http</module>
410 will always attempt to send the <code>Content-Length</code>. But
411 if the body is large and the original request used chunked
412 encoding, then chunked encoding may also be used in the upstream
413 request. You can control this selection using <a
414 href="../env.html">environment variables</a>. Setting
415 <code>proxy-sendcl</code> ensures maximum compatibility with
416 upstream servers by always sending the
417 <code>Content-Length</code>, while setting
418 <code>proxy-sendchunked</code> minimizes resource usage by using
419 chunked encoding.</p>
421 <p>Under some circumstances, the server must spool request bodies
422 to disk to satisfy the requested handling of request bodies. For
423 example, this spooling will occur if the original body was sent with
424 chunked encoding (and is large), but the administrator has
425 asked for backend requests to be sent with Content-Length or as HTTP/1.0.
426 This spooling can also occur if the request body already has a
427 Content-Length header, but the server is configured to filter incoming
430 <p><directive module="core">LimitRequestBody</directive> only applies to
431 request bodies that the server will spool to disk</p>
433 </section> <!-- /request-bodies -->
435 <section id="x-headers"><title>Reverse Proxy Request Headers</title>
437 <p>When acting in a reverse-proxy mode (using the <directive
438 module="mod_proxy">ProxyPass</directive> directive, for example),
439 <module>mod_proxy_http</module> adds several request headers in
440 order to pass information to the origin server. These headers
444 <dt><code>X-Forwarded-For</code></dt>
445 <dd>The IP address of the client.</dd>
446 <dt><code>X-Forwarded-Host</code></dt>
447 <dd>The original host requested by the client in the <code>Host</code>
448 HTTP request header.</dd>
449 <dt><code>X-Forwarded-Server</code></dt>
450 <dd>The hostname of the proxy server.</dd>
453 <p>Be careful when using these headers on the origin server, since
454 they will contain more than one (comma-separated) value if the
455 original request already contained one of these headers. For
456 example, you can use <code>%{X-Forwarded-For}i</code> in the log
457 format string of the origin server to log the original clients IP
458 address, but you may get more than one address if the request
459 passes through several proxies.</p>
461 <p>See also the <directive
462 module="mod_proxy">ProxyPreserveHost</directive> and <directive
463 module="mod_proxy">ProxyVia</directive> directives, which control
464 other request headers.</p>
466 <p>Note: If you need to specify custom request headers to be
467 added to the forwarded request, use the
468 <directive module="mod_headers">RequestHeader</directive>
471 </section> <!--/x-headers -->
474 <directivesynopsis type="section">
476 <description>Container for directives applied to proxied resources</description>
477 <syntax><Proxy <var>wildcard-url</var>> ...</Proxy></syntax>
478 <contextlist><context>server config</context><context>virtual host</context>
482 <p>Directives placed in <directive type="section">Proxy</directive>
483 sections apply only to matching proxied content. Shell-style wildcards are
486 <p>For example, the following will allow only hosts in
487 <code>yournetwork.example.com</code> to access content via your proxy
490 <highlight language="config">
492 Require host yournetwork.example.com
496 <p>The following example will process all files in the <code>foo</code>
497 directory of <code>example.com</code> through the <code>INCLUDES</code>
498 filter when they are sent through the proxy server:</p>
500 <highlight language="config">
501 <Proxy http://example.com/foo/*>
502 SetOutputFilter INCLUDES
506 <p>The next example will allow web clients from the specified IP
507 addresses to issue <code>CONNECT</code> requests to access the
508 <code>https://www.example.com/</code> SSL server if
509 <module>mod_proxy_connect</module> is enabled.
512 <highlight language="config">
513 <Proxy www.example.com:443>
514 Require ip 192.168.0.0/16
518 <note><title>Differences from the Location configuration section</title>
519 <p>A backend URL matches the configuration section if it begins with the
520 the <var>wildcard-url</var> string, even if the last path segment in the
521 directive only matches a prefix of the backend URL. For example,
522 <Proxy http://example.com/foo> matches all of
523 http://example.com/foo, http://example.com/foo/bar, and
524 http://example.com/foobar. The matching of the final URL differs
525 from the behavior of the <directive type="section" module="core"
526 >Location</directive> section, which for purposes of this note
527 treats the final path component as if it ended in a slash.</p>
528 <p>For more control over the matching, see <directive type="section"
529 >ProxyMatch</directive>.</p>
533 <seealso><directive type="section" module="mod_proxy">ProxyMatch</directive></seealso>
537 <name>ProxyBadHeader</name>
538 <description>Determines how to handle bad header lines in a
539 response</description>
540 <syntax>ProxyBadHeader IsError|Ignore|StartBody</syntax>
541 <default>ProxyBadHeader IsError</default>
542 <contextlist><context>server config</context><context>virtual host</context>
546 <p>The <directive>ProxyBadHeader</directive> directive determines the
547 behavior of <module>mod_proxy</module> if it receives syntactically invalid
548 response header lines (<em>i.e.</em> containing no colon) from the origin
549 server. The following arguments are possible:</p>
552 <dt><code>IsError</code></dt>
553 <dd>Abort the request and end up with a 502 (Bad Gateway) response. This is
554 the default behavior.</dd>
556 <dt><code>Ignore</code></dt>
557 <dd>Treat bad header lines as if they weren't sent.</dd>
559 <dt><code>StartBody</code></dt>
560 <dd>When receiving the first bad header line, finish reading the headers and
561 treat the remainder as body. This helps to work around buggy backend servers
562 which forget to insert an empty line between the headers and the body.</dd>
567 <directivesynopsis type="section">
568 <name>ProxyMatch</name>
569 <description>Container for directives applied to regular-expression-matched
570 proxied resources</description>
571 <syntax><ProxyMatch <var>regex</var>> ...</ProxyMatch></syntax>
572 <contextlist><context>server config</context><context>virtual host</context>
576 <p>The <directive type="section">ProxyMatch</directive> directive is
577 identical to the <directive module="mod_proxy"
578 type="section">Proxy</directive> directive, except that it matches URLs
579 using <glossary ref="regex">regular expressions</glossary>.</p>
581 <p>From 2.4.8 onwards, named groups and backreferences are captured and
582 written to the environment with the corresponding name prefixed with
583 "MATCH_" and in upper case. This allows elements of URLs to be referenced
584 from within <a href="../expr.html">expressions</a> and modules like
585 <module>mod_rewrite</module>. In order to prevent confusion, numbered
586 (unnamed) backreferences are ignored. Use named groups instead.</p>
588 <highlight language="config">
589 <ProxyMatch ^http://(?<sitename>[^/]+)>
590 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
594 <seealso><directive type="section" module="mod_proxy">Proxy</directive></seealso>
598 <name>ProxyPreserveHost</name>
599 <description>Use incoming Host HTTP request header for proxy
600 request</description>
601 <syntax>ProxyPreserveHost On|Off</syntax>
602 <default>ProxyPreserveHost Off</default>
603 <contextlist><context>server config</context><context>virtual host</context>
604 <context>directory</context>
606 <compatibility>Usable in directory
607 context in 2.3.3 and later.</compatibility>
610 <p>When enabled, this option will pass the Host: line from the incoming
611 request to the proxied host, instead of the hostname specified in the
612 <directive module="mod_proxy">ProxyPass</directive> line.</p>
614 <p>This option should normally be turned <code>Off</code>. It is mostly
615 useful in special configurations like proxied mass name-based virtual
616 hosting, where the original Host header needs to be evaluated by the
622 <name>ProxyRequests</name>
623 <description>Enables forward (standard) proxy requests</description>
624 <syntax>ProxyRequests On|Off</syntax>
625 <default>ProxyRequests Off</default>
626 <contextlist><context>server config</context><context>virtual host</context>
630 <p>This allows or prevents Apache httpd from functioning as a forward proxy
631 server. (Setting ProxyRequests to <code>Off</code> does not disable use of
632 the <directive module="mod_proxy">ProxyPass</directive> directive.)</p>
634 <p>In a typical reverse proxy or gateway configuration, this
635 option should be set to
636 <code>Off</code>.</p>
638 <p>In order to get the functionality of proxying HTTP or FTP sites, you
639 need also <module>mod_proxy_http</module> or <module>mod_proxy_ftp</module>
640 (or both) present in the server.</p>
642 <p>In order to get the functionality of (forward) proxying HTTPS sites, you
643 need <module>mod_proxy_connect</module> enabled in the server.</p>
645 <note type="warning"><title>Warning</title>
646 <p>Do not enable proxying with <directive
647 module="mod_proxy">ProxyRequests</directive> until you have <a
648 href="#access">secured your server</a>. Open proxy servers are dangerous
649 both to your network and to the Internet at large.</p>
652 <seealso><a href="#forwardreverse">Forward and Reverse Proxies/Gateways</a></seealso>
656 <name>ProxyRemote</name>
657 <description>Remote proxy used to handle certain requests</description>
658 <syntax>ProxyRemote <var>match</var> <var>remote-server</var></syntax>
659 <contextlist><context>server config</context><context>virtual host</context>
663 <p>This defines remote proxies to this proxy. <var>match</var> is either the
664 name of a URL-scheme that the remote server supports, or a partial URL
665 for which the remote server should be used, or <code>*</code> to indicate
666 the server should be contacted for all requests. <var>remote-server</var> is
667 a partial URL for the remote server. Syntax:</p>
670 <dfn>remote-server</dfn> =
671 <var>scheme</var>://<var>hostname</var>[:<var>port</var>]
674 <p><var>scheme</var> is effectively the protocol that should be used to
675 communicate with the remote server; only <code>http</code> and <code>https</code>
676 are supported by this module. When using <code>https</code>, the requests
677 are forwarded through the remote proxy using the HTTP CONNECT method.</p>
679 <example><title>Example</title>
680 <highlight language="config">
681 ProxyRemote http://goodguys.example.com/ http://mirrorguys.example.com:8000
682 ProxyRemote * http://cleverproxy.localdomain
683 ProxyRemote ftp http://ftpproxy.mydomain:8080
687 <p>In the last example, the proxy will forward FTP requests, encapsulated
688 as yet another HTTP proxy request, to another proxy which can handle
691 <p>This option also supports reverse proxy configuration; a backend
692 webserver can be embedded within a virtualhost URL space even if that
693 server is hidden by another forward proxy.</p>
698 <name>ProxyRemoteMatch</name>
699 <description>Remote proxy used to handle requests matched by regular
700 expressions</description>
701 <syntax>ProxyRemoteMatch <var>regex</var> <var>remote-server</var></syntax>
702 <contextlist><context>server config</context><context>virtual host</context>
706 <p>The <directive>ProxyRemoteMatch</directive> is identical to the
707 <directive module="mod_proxy">ProxyRemote</directive> directive, except that
708 the first argument is a <glossary ref="regex">regular expression</glossary>
709 match against the requested URL.</p>
714 <name>BalancerGrowth</name>
715 <description>Number of additional Balancers that can be added Post-configuration</description>
716 <syntax>BalancerGrowth <var>#</var></syntax>
717 <default>BalancerGrowth 5</default>
718 <contextlist><context>server config</context><context>virtual host</context></contextlist>
719 <compatibility>BalancerGrowth is only available in Apache HTTP Server 2.3.13
720 and later.</compatibility>
722 <p>This directive allows for growth potential in the number of
723 Balancers available for a virtualhost in addition to the
724 number pre-configured. It only takes effect if there is at
725 least one pre-configured Balancer.</p>
730 <name>BalancerPersist</name>
731 <description>Attempt to persist changes made by the Balancer Manager across restarts.</description>
732 <syntax>BalancerPersist On|Off</syntax>
733 <default>BalancerPersist Off</default>
734 <contextlist><context>server config</context><context>virtual host</context></contextlist>
735 <compatibility>BalancerPersist is only available in Apache HTTP Server 2.4.4 and later.</compatibility>
737 <p>This directive will cause the shared memory storage associated
738 with the balancers and balancer members to be persisted across
739 restarts. This allows these local changes to not be lost during the
740 normal restart/graceful state transitions.</p>
745 <name>ProxyPassInherit</name>
746 <description>Inherit ProxyPass directives defined from the main server</description>
747 <syntax>ProxyPassInherit On|Off</syntax>
748 <default>ProxyPassInherit On</default>
749 <contextlist><context>server config</context><context>virtual host</context></contextlist>
750 <compatibility>ProxyPassInherit is only available in Apache HTTP Server 2.4.5 and later.
753 <p>This directive will cause the current server/vhost to "inherit"
754 <directive module="mod_proxy">ProxyPass</directive>
755 directives defined in the main server. This can cause issues and
756 inconsistent behavior if using the Balancer Manager for dynamic changes
757 and so should be disabled if using that feature.</p>
758 <p>The setting in the global server defines the default for all vhosts.</p>
759 <p>Disabling ProxyPassInherit also disables <directive module="mod_proxy">BalancerInherit</directive>.</p>
764 <name>BalancerInherit</name>
765 <description>Inherit proxy Balancers/Workers defined from the main server</description>
766 <syntax>BalancerInherit On|Off</syntax>
767 <default>BalancerInherit On</default>
768 <contextlist><context>server config</context><context>virtual host</context></contextlist>
769 <compatibility>BalancerInherit is only available in Apache HTTP Server 2.4.5 and later.</compatibility>
771 <p>This directive will cause the current server/vhost to "inherit"
772 Balancers and Workers defined in the main server. This can cause issues and
773 inconsistent behavior if using the Balancer Manager for dynamic changes
774 and so should be disabled if using that feature.</p>
775 <p>The setting in the global server defines the default for all vhosts.</p>
776 <p>Disabling <directive module="mod_proxy">ProxyPassInherit</directive> also disables BalancerInherit.</p>
781 <name>BalancerMember</name>
782 <description>Add a member to a load balancing group</description>
783 <syntax>BalancerMember [<var>balancerurl</var>] <var>url</var> [<var
784 >key=value [key=value ...]]</var></syntax>
785 <contextlist><context>directory</context>
788 <p>This directive adds a member to a load balancing group. It can be used
789 within a <code><Proxy <var>balancer://</var>...></code> container
790 directive and can take any of the key value pair parameters available to
791 <directive module="mod_proxy">ProxyPass</directive> directives.</p>
792 <p>One additional parameter is available only to <directive>BalancerMember</directive> directives:
793 <var>loadfactor</var>. This is the member load factor - a number between 1
794 (default) and 100, which defines the weighted load to be applied to the
795 member in question.</p>
796 <p>The <var>balancerurl</var> is only needed when not within a
797 <code><Proxy <var>balancer://</var>...></code>
798 container directive. It corresponds to the url of a balancer defined in
799 <directive module="mod_proxy">ProxyPass</directive> directive.</p>
800 <p>The path component of the balancer URL in any
801 <code><Proxy <var>balancer://</var>...></code> container directive
803 <p>Trailing slashes should typically be removed from the URL of a
804 <directive>BalancerMember</directive>.</p>
809 <name>ProxySet</name>
810 <description>Set various Proxy balancer or member parameters</description>
811 <syntax>ProxySet <var>url</var> <var>key=value [key=value ...]</var></syntax>
812 <contextlist><context>directory</context>
815 <p>This directive is used as an alternate method of setting any of the
816 parameters available to Proxy balancers and workers normally done via the
817 <directive module="mod_proxy">ProxyPass</directive> directive. If used
818 within a <code><Proxy <var>balancer url|worker url</var>></code>
819 container directive, the <var>url</var> argument is not required. As a side
820 effect the respective balancer or worker gets created. This can be useful
821 when doing reverse proxying via a
822 <directive module="mod_rewrite">RewriteRule</directive> instead of a
823 <directive module="mod_proxy">ProxyPass</directive> directive.</p>
826 <highlight language="config">
827 <Proxy balancer://hotcluster>
828 BalancerMember http://www2.example.com:8080 loadfactor=1
829 BalancerMember http://www3.example.com:8080 loadfactor=2
830 ProxySet lbmethod=bytraffic
835 <highlight language="config">
836 <Proxy http://backend>
837 ProxySet keepalive=On
841 <highlight language="config">
842 ProxySet balancer://foo lbmethod=bytraffic timeout=15
845 <highlight language="config">
846 ProxySet ajp://backend:7001 timeout=15
849 <note type="warning"><title>Warning</title>
850 <p>Keep in mind that the same parameter key can have a different meaning
851 depending whether it is applied to a balancer or a worker, as shown by
852 the two examples above regarding timeout.</p>
859 <name>ProxyPass</name>
860 <description>Maps remote servers into the local server URL-space</description>
861 <syntax>ProxyPass [<var>path</var>] !|<var>url</var> [<var>key=value</var>
862 <var>[key=value</var> ...]] [nocanon] [interpolate] [noquery]</syntax>
863 <contextlist><context>server config</context><context>virtual host</context>
864 <context>directory</context>
866 <compatibility>Unix Domain Socket (UDS) support added in 2.4.7</compatibility>
869 <p>This directive allows remote servers to be mapped into the
870 space of the local server. The local server does not act as a
871 proxy in the conventional sense but appears to be a mirror of the
872 remote server. The local server is often called a <dfn>reverse
873 proxy</dfn> or <dfn>gateway</dfn>. The <var>path</var> is the name of
874 a local virtual path; <var>url</var> is a partial URL for the
875 remote server and cannot include a query string.</p>
877 <note><strong>Note: </strong>This directive is not supported within
878 <directive type="section" module="core">Directory</directive> and
879 <directive type="section" module="core">Files</directive> containers.</note>
881 <note type="warning">The <directive
882 module="mod_proxy">ProxyRequests</directive> directive should
883 usually be set <strong>off</strong> when using
884 <directive>ProxyPass</directive>.</note>
886 <p>In 2.4.7 and later, support for using a Unix Domain Socket is available by using a target
887 which prepends <code>unix:/path/lis.sock|</code>. For example, to proxy
888 HTTP and target the UDS at /home/www/socket, you would use
889 <code>unix:/home/www.socket|http://localhost/whatever/</code>. Since
890 the socket is local, the hostname used (in this case <code>localhost</code>)
891 is moot, but it is passed as the Host: header value of the request.</p>
893 <note><strong>Note:</strong> The path associated with the <code>unix:</code>
894 URL is <directive>DefaultRuntimeDir</directive> aware.</note>
896 <note><strong>Note:</strong> <directive>RewriteRule</directive> requires
897 the <code>[P,NE]</code> option to prevent the <code>'|'</code> character
898 from being escaped.</note>
900 <p>When used inside a <directive type="section" module="core"
901 >Location</directive> section, the first argument is omitted and the local
902 directory is obtained from the <directive type="section" module="core"
903 >Location</directive>. The same will occur inside a
904 <directive type="section" module="core">LocationMatch</directive> section;
905 however, ProxyPass does not interpret the regexp as such, so it is necessary
906 to use <directive>ProxyPassMatch</directive> in this situation instead.</p>
908 <p>Suppose the local server has address <code>http://example.com/</code>;
911 <highlight language="config">
912 <Location "/mirror/foo/">
913 ProxyPass "http://backend.example.com/"
917 <p>will cause a local request for
918 <code>http://example.com/mirror/foo/bar</code> to be internally converted
919 into a proxy request to <code>http://backend.example.com/bar</code>.</p>
921 <p>If you require a more flexible reverse-proxy configuration, see the
922 <directive module="mod_rewrite">RewriteRule</directive> directive with the
923 <code>[P]</code> flag.</p>
925 <p>The following alternative syntax is possible; however, it can carry a
926 performance penalty when present in very large numbers. The advantage of
927 the below syntax is that it allows for dynamic control via the
928 <a href="mod_proxy_balancer.html#balancer_manager">Balancer Manager</a> interface:</p>
930 <highlight language="config">
931 ProxyPass "/mirror/foo/" "http://backend.example.com/"
934 <note type="warning">
935 <p>If the first argument ends with a trailing <strong>/</strong>, the second
936 argument should also end with a trailing <strong>/</strong>, and vice
937 versa. Otherwise, the resulting requests to the backend may miss some
938 needed slashes and do not deliver the expected results.
942 <p>The <code>!</code> directive is useful in situations where you don't want
943 to reverse-proxy a subdirectory, <em>e.g.</em></p>
945 <highlight language="config">
946 <Location "/mirror/foo/">
947 ProxyPass "http://backend.example.com/"
949 <Location "/mirror/foo/i">
954 <highlight language="config">
955 ProxyPass "/mirror/foo/i" "!"
956 ProxyPass "/mirror/foo" "http://backend.example.com"
959 <p>will proxy all requests to <code>/mirror/foo</code> to
960 <code>backend.example.com</code> <em>except</em> requests made to
961 <code>/mirror/foo/i</code>.</p>
963 <note type="warning"><title>Ordering ProxyPass Directives</title>
964 <p>The configured <directive module="mod_proxy">ProxyPass</directive>
965 and <directive module="mod_proxy">ProxyPassMatch</directive>
966 rules are checked in the order of configuration. The first rule that
967 matches wins. So usually you should sort conflicting
968 <directive module="mod_proxy">ProxyPass</directive> rules starting with the
969 longest URLs first. Otherwise, later rules for longer URLS will be hidden
970 by any earlier rule which uses a leading substring of the URL. Note that
971 there is some relation with worker sharing. In contrast, only one
972 <directive module="mod_proxy">ProxyPass</directive> directive can be placed
973 in a <directive module="core">Location</directive> block, and the most
974 specific location will take precedence.</p>
976 <p>For the same reasons, exclusions must come <em>before</em> the
977 general <directive>ProxyPass</directive> directives.</p>
979 </note> <!-- /ordering_proxypass -->
981 <p><strong>ProxyPass <code>key=value</code> Parameters</strong></p>
983 <p>In Apache HTTP Server 2.1 and later, mod_proxy supports pooled
984 connections to a backend server. Connections created on demand
985 can be retained in a pool for future use. Limits on the pool size
986 and other settings can be coded on
987 the <directive>ProxyPass</directive> directive
988 using <code>key=value</code> parameters, described in the tables
991 <p>By default, mod_proxy will allow and retain the maximum number of
992 connections that could be used simultaneously by that web server child
993 process. Use the <code>max</code> parameter to reduce the number from
994 the default. Use the <code>ttl</code> parameter to set an optional
995 time to live; connections which have been unused for at least
996 <code>ttl</code> seconds will be closed. <code>ttl</code> can be used
997 to avoid using a connection which is subject to closing because of the
998 backend server's keep-alive timeout.</p>
1000 <p>The pool of connections is maintained per web server child
1001 process, and <code>max</code> and other settings are not coordinated
1002 among all child processes, except when only one child process is allowed
1003 by configuration or MPM design.</p>
1005 <example><title>Example</title>
1006 <highlight language="config">
1007 ProxyPass "/example" "http://backend.example.com" max=20 ttl=120 retry=300
1011 <table border="2"><tr><th>BalancerMember parameters</th></tr></table>
1013 <tr><th>Parameter</th>
1015 <th>Description</th></tr>
1018 <td>Minimum number of connection pool entries, unrelated to the
1019 actual number of connections. This only needs to be modified from the
1020 default for special circumstances where heap memory associated with the
1021 backend connections should be preallocated or retained.</td></tr>
1024 <td>Maximum number of connections that will be allowed to the
1025 backend server. The default for this limit is the number of threads
1026 per process in the active MPM. In the Prefork MPM, this is always 1;
1027 while with other MPMs, it is controlled by the
1028 <directive>ThreadsPerChild</directive> directive.</td></tr>
1031 <td>Retained connection pool entries above this limit are freed
1032 during certain operations if they have been unused for longer than
1033 the time to live, controlled by the <code>ttl</code> parameter. If
1034 the connection pool entry has an associated connection, it will be
1035 closed. This only needs to be modified from the default for special
1036 circumstances where connection pool entries and any associated
1037 connections which have exceeded the time to live need to be freed or
1038 closed more aggressively.</td></tr>
1039 <tr><td>acquire</td>
1041 <td>If set, this will be the maximum time to wait for a free
1042 connection in the connection pool, in milliseconds. If there are no free
1043 connections in the pool, the Apache httpd will return <code>SERVER_BUSY</code>
1044 status to the client.
1046 <tr><td>connectiontimeout</td>
1048 <td>Connect timeout in seconds.
1049 The number of seconds Apache httpd waits for the creation of a connection to
1050 the backend to complete. By adding a postfix of ms, the timeout can be
1051 also set in milliseconds.
1053 <tr><td>disablereuse</td>
1055 <td>This parameter should be used when you want to force mod_proxy
1056 to immediately close a connection to the backend after being used, and
1057 thus, disable its persistent connection and pool for that backend.
1058 This helps in various situations where a firewall between Apache
1060 the backend server (regardless of protocol) tends to silently
1061 drop connections or when backends themselves may be under round-
1062 robin DNS. To disable connection pooling reuse,
1063 set this property value to <code>On</code>.
1065 <tr><td>enablereuse</td>
1067 <td>This is the inverse of 'disablereuse' above, provided as a
1068 convenience for scheme handlers that require opt-in for connection
1069 reuse (such as <module>mod_proxy_fcgi</module>).
1071 <tr><td>flushpackets</td>
1073 <td>Determines whether the proxy module will auto-flush the output
1074 brigade after each "chunk" of data. 'off' means that it will flush
1075 only when needed; 'on' means after each chunk is sent; and
1076 'auto' means poll/wait for a period of time and flush if
1077 no input has been received for 'flushwait' milliseconds.
1078 Currently, this is in effect only for AJP.
1080 <tr><td>flushwait</td>
1082 <td>The time to wait for additional input, in milliseconds, before
1083 flushing the output brigade if 'flushpackets' is 'auto'.
1085 <tr><td>iobuffersize</td>
1087 <td>Adjusts the size of the internal scratchpad IO buffer. This allows you
1088 to override the <directive>ProxyIOBufferSize</directive> for a specific worker.
1089 This must be at least 512 or set to 0 for the system default of 8192.
1091 <tr><td>keepalive</td>
1093 <td><p>This parameter should be used when you have a firewall between your
1094 Apache httpd and the backend server, which tends to drop inactive connections.
1095 This flag will tell the Operating System to send <code>KEEP_ALIVE</code>
1096 messages on inactive connections and thus prevent the firewall
1097 from dropping the connection.
1098 To enable keepalive, set this property value to <code>On</code>. </p>
1099 <p>The frequency of initial and subsequent TCP keepalive probes
1100 depends on global OS settings, and may be as high as 2 hours. To be useful,
1101 the frequency configured in the OS must be smaller than the threshold used
1102 by the firewall.</p>
1106 <td>Sets the load balancer cluster set that the worker is a member
1107 of. The load balancer will try all members of a lower numbered
1108 lbset before trying higher numbered ones.
1112 <td>Ping property tells the webserver to "test" the connection to
1113 the backend before forwarding the request. For negative values,
1114 the test is a simple socket check; for positive values, it's
1115 a more functional check, dependent upon the protocol. For AJP, it causes
1116 <module>mod_proxy_ajp</module> to send a <code>CPING</code>
1117 request on the ajp13 connection (implemented on Tomcat 3.3.2+, 4.1.28+
1118 and 5.0.13+). For HTTP, it causes <module>mod_proxy_http</module>
1119 to send a <code>100-Continue</code> to the backend (only valid for
1120 HTTP/1.1 - for non HTTP/1.1 backends, this property has no
1121 effect). In both cases, the parameter is the delay in seconds to wait
1123 This feature has been added to avoid problems with hung and
1125 This will increase the network traffic during the normal operation
1126 which could be an issue, but it will lower the
1127 traffic in case some of the cluster nodes are down or busy.
1128 By adding a postfix of ms, the delay can be also set in
1131 <tr><td>receivebuffersize</td>
1133 <td>Adjusts the size of the explicit (TCP/IP) network buffer size for
1134 proxied connections. This allows you to override the
1135 <directive>ProxyReceiveBufferSize</directive> for a specific worker.
1136 This must be at least 512 or set to 0 for the system default.
1138 <tr><td>redirect</td>
1140 <td>Redirection Route of the worker. This value is usually
1141 set dynamically to enable safe removal of the node from
1142 the cluster. If set, all requests without session id will be
1143 redirected to the BalancerMember that has route parameter
1144 equal to this value.
1148 <td>Connection pool worker retry timeout in seconds.
1149 If the connection pool worker to the backend server is in the error state,
1150 Apache httpd will not forward any requests to that server until the timeout
1151 expires. This enables to shut down the backend server for maintenance
1152 and bring it back online later. A value of 0 means always retry workers
1153 in an error state with no timeout.
1157 <td>Route of the worker when used inside load balancer.
1158 The route is a value appended to session id.
1162 <td>Single letter value defining the initial status of
1165 <tr><td><code>D</code></td><td>Worker is disabled and will not accept any requests; will be
1166 automatically retried.</td></tr>
1167 <tr><td><code>S</code></td><td>Worker is administratively stopped; will not accept requests
1168 and will not be automatically retried</td></tr>
1169 <tr><td><code>I</code></td><td>Worker is in ignore-errors mode and will always be considered available.</td></tr>
1170 <tr><td><code>H</code></td><td>Worker is in hot-standby mode and will only be used if no other
1171 viable workers are available.</td></tr>
1172 <tr><td><code>E</code></td><td>Worker is in an error state.</td></tr>
1173 <tr><td><code>N</code></td><td>Worker is in drain mode and will only accept existing sticky sessions
1174 destined for itself and ignore all other requests.</td></tr>
1176 Status can be set (which is the default) by prepending with '+' or
1177 cleared by prepending with '-'.
1178 Thus, a setting of 'S-E' sets this worker to Stopped and
1179 clears the in-error flag.
1181 <tr><td>timeout</td>
1182 <td><directive module="mod_proxy">ProxyTimeout</directive></td>
1183 <td>Connection timeout in seconds.
1184 The number of seconds Apache httpd waits for data sent by / to the backend.
1188 <td>Time to live for inactive connections and associated connection
1189 pool entries, in seconds. Once reaching this limit, a
1190 connection will not be used again; it will be closed at some
1193 <tr><td>flusher</td>
1195 <td><p>Name of the provider used by <module>mod_proxy_fdpass</module>.
1196 See the documentation of this module for more details.</p>
1201 <p>If the Proxy directive scheme starts with the
1202 <code>balancer://</code> (eg: <code>balancer://cluster</code>,
1203 any path information is ignored), then a virtual worker that does not really
1204 communicate with the backend server will be created. Instead, it is responsible
1205 for the management of several "real" workers. In that case, the special set of
1206 parameters can be added to this virtual worker. See <module>mod_proxy_balancer</module>
1207 for more information about how the balancer works.
1209 <table border="2"><tr><th>Balancer parameters</th></tr></table>
1211 <tr><th>Parameter</th>
1213 <th>Description</th></tr>
1214 <tr><td>lbmethod</td>
1216 <td>Balancer load-balance method. Select the load-balancing scheduler
1217 method to use. Either <code>byrequests</code>, to perform weighted
1218 request counting; <code>bytraffic</code>, to perform weighted
1219 traffic byte count balancing; or <code>bybusyness</code>, to perform
1220 pending request balancing. The default is <code>byrequests</code>.
1222 <tr><td>maxattempts</td>
1223 <td>One less than the number of workers, or 1 with a single worker.</td>
1224 <td>Maximum number of failover attempts before giving up.
1226 <tr><td>nofailover</td>
1228 <td>If set to <code>On</code>, the session will break if the worker is in
1229 error state or disabled. Set this value to <code>On</code> if backend
1230 servers do not support session replication.
1232 <tr><td>stickysession</td>
1234 <td>Balancer sticky session name. The value is usually set to something
1235 like <code>JSESSIONID</code> or <code>PHPSESSIONID</code>,
1236 and it depends on the backend application server that support sessions.
1237 If the backend application server uses different names for cookies
1238 and url encoded id (like servlet containers), use | to separate them.
1239 The first part is for the cookie; the second is for the path.<br />
1240 Available in Apache HTTP Server 2.4.4 and later.
1242 <tr><td>stickysessionsep</td>
1244 <td>Sets the separation symbol in the session cookie. Some backend application servers
1245 do not use the '.' as the symbol. For example, the Oracle Weblogic server uses
1246 '!'. The correct symbol can be set using this option. The setting of 'Off'
1247 signifies that no symbol is used.
1249 <tr><td>scolonpathdelim</td>
1251 <td>If set to <code>On</code>, the semi-colon character ';' will be
1252 used as an additional sticky session path delimiter/separator. This
1253 is mainly used to emulate mod_jk's behavior when dealing with paths such
1254 as <code>JSESSIONID=6736bcf34;foo=aabfa</code>
1256 <tr><td>timeout</td>
1258 <td>Balancer timeout in seconds. If set, this will be the maximum time
1259 to wait for a free worker. The default is to not wait.
1261 <tr><td>failonstatus</td>
1263 <td>A single or comma-separated list of HTTP status codes. If set, this will
1264 force the worker into error state when the backend returns any status code
1265 in the list. Worker recovery behaves the same as other worker errors.
1267 <tr><td>failontimeout</td>
1269 <td>If set, an IO read timeout after a request is sent to the backend will
1270 force the worker into error state. Worker recovery behaves the same as other
1271 worker errors.<br />
1272 Available in Apache HTTP Server 2.4.5 and later.
1275 <td><auto></td>
1276 <td>The protective nonce used in the <code>balancer-manager</code> application page.
1277 The default is to use an automatically determined UUID-based
1278 nonce, to provide for further protection for the page. If set,
1279 then the nonce is set to that value. A setting of <code>None</code>
1280 disables all nonce checking.
1281 <note><title>Note</title>
1282 <p>In addition to the nonce, the <code>balancer-manager</code> page
1283 should be protected via an ACL.</p>
1288 <td>Number of additional BalancerMembers to allow to be added
1289 to this balancer in addition to those defined at configuration.
1291 <tr><td>forcerecovery</td>
1293 <td>Force the immediate recovery of all workers without considering the
1294 retry parameter of the workers if all workers of a balancer are
1295 in error state. There might be cases where an already overloaded backend
1296 can get into deeper trouble if the recovery of all workers is enforced
1297 without considering the retry parameter of each worker. In this case,
1298 set to <code>Off</code>.<br />
1299 Available in Apache HTTP Server 2.4.2 and later.
1303 <p>A sample balancer setup:</p>
1304 <highlight language="config">
1305 ProxyPass "/special-area" "http://special.example.com" smax=5 max=10
1306 ProxyPass "/" "balancer://mycluster/" stickysession=JSESSIONID|jsessionid nofailover=On
1307 <Proxy balancer://mycluster>
1308 BalancerMember ajp://1.2.3.4:8009
1309 BalancerMember ajp://1.2.3.5:8009 loadfactor=20
1310 # Less powerful server, don't send as many requests there,
1311 BalancerMember ajp://1.2.3.6:8009 loadfactor=5
1315 <p>Setting up a hot-standby that will only be used if no other
1316 members are available:</p>
1317 <highlight language="config">
1318 ProxyPass "/" "balancer://hotcluster/"
1319 <Proxy balancer://hotcluster>
1320 BalancerMember ajp://1.2.3.4:8009 loadfactor=1
1321 BalancerMember ajp://1.2.3.5:8009 loadfactor=2
1322 # The server below is on hot standby
1323 BalancerMember ajp://1.2.3.6:8009 status=+H
1324 ProxySet lbmethod=bytraffic
1328 <p><strong>Additional ProxyPass Keywords</strong></p>
1330 <p>Normally, mod_proxy will canonicalise ProxyPassed URLs.
1331 But this may be incompatible with some backends, particularly those
1332 that make use of <var>PATH_INFO</var>. The optional <var>nocanon</var>
1333 keyword suppresses this and passes the URL path "raw" to the
1334 backend. Note that this keyword may affect the security of your backend,
1335 as it removes the normal limited protection against URL-based attacks
1336 provided by the proxy.</p>
1338 <p>Normally, mod_proxy will include the query string when
1339 generating the <var>SCRIPT_FILENAME</var> environment variable.
1340 The optional <var>noquery</var> keyword (available in
1341 httpd 2.4.1 and later) prevents this.</p>
1343 <p>The optional <var>interpolate</var> keyword, in combination with
1344 <directive>ProxyPassInterpolateEnv</directive>, causes the ProxyPass
1345 to interpolate environment variables, using the syntax
1346 <var>${VARNAME}</var>. Note that many of the standard CGI-derived
1347 environment variables will not exist when this interpolation happens,
1348 so you may still have to resort to <module>mod_rewrite</module>
1349 for complex rules. Also note that interpolation is not supported
1350 within the scheme portion of a URL. Dynamic determination of the
1351 scheme can be accomplished with <module>mod_rewrite</module> as in the
1352 following example.</p>
1354 <highlight language="config">
1357 RewriteCond %{HTTPS} =off
1358 RewriteRule . - [E=protocol:http]
1359 RewriteCond %{HTTPS} =on
1360 RewriteRule . - [E=protocol:https]
1362 RewriteRule ^/mirror/foo/(.*) %{ENV:protocol}://backend.example.com/$1 [P]
1363 ProxyPassReverse "/mirror/foo/" "http://backend.example.com/"
1364 ProxyPassReverse "/mirror/foo/" "https://backend.example.com/"
1367 </directivesynopsis>
1370 <name>ProxyPassMatch</name>
1371 <description>Maps remote servers into the local server URL-space using regular expressions</description>
1372 <syntax>ProxyPassMatch [<var>regex</var>] !|<var>url</var> [<var>key=value</var>
1373 <var>[key=value</var> ...]]</syntax>
1374 <contextlist><context>server config</context><context>virtual host</context>
1375 <context>directory</context>
1379 <p>This directive is equivalent to <directive module="mod_proxy">ProxyPass</directive>
1380 but makes use of regular expressions instead of simple prefix matching. The
1381 supplied regular expression is matched against the <var>url</var>, and if it
1382 matches, the server will substitute any parenthesized matches into the given
1383 string and use it as a new <var>url</var>.</p>
1385 <note><strong>Note: </strong>This directive cannot be used within a
1386 <code><Directory></code> context.</note>
1388 <p>Suppose the local server has address <code>http://example.com/</code>;
1391 <highlight language="config">
1392 ProxyPassMatch "^/(.*\.gif)$" "http://backend.example.com/$1"
1395 <p>will cause a local request for
1396 <code>http://example.com/foo/bar.gif</code> to be internally converted
1397 into a proxy request to <code>http://backend.example.com/foo/bar.gif</code>.</p>
1398 <note><title>Note</title>
1399 <p>The URL argument must be parsable as a URL <em>before</em> regexp
1400 substitutions (as well as after). This limits the matches you can use.
1401 For instance, if we had used</p>
1402 <highlight language="config">
1403 ProxyPassMatch "^(/.*\.gif)$" "http://backend.example.com:8000$1"
1405 <p>in our previous example, it would fail with a syntax error
1406 at server startup. This is a bug (PR 46665 in the ASF bugzilla),
1407 and the workaround is to reformulate the match:</p>
1408 <highlight language="config">
1409 ProxyPassMatch "^/(.*\.gif)$" "http://backend.example.com:8000/$1"
1412 <p>The <code>!</code> directive is useful in situations where you don't want
1413 to reverse-proxy a subdirectory.</p>
1415 <p>When used inside a <directive type="section" module="core"
1416 >LocationMatch</directive> section, the first argument is omitted and the
1417 regexp is obtained from the <directive type="section" module="core"
1418 >LocationMatch</directive>.</p>
1420 <p>If you require a more flexible reverse-proxy configuration, see the
1421 <directive module="mod_rewrite">RewriteRule</directive> directive with the
1422 <code>[P]</code> flag.</p>
1425 <title>Default Substitution</title>
1426 <p>When the URL parameter doesn't use any backreferences into the regular
1427 expression, the original URL will be appended to the URL parameter.
1431 <note type="warning">
1432 <title>Security Warning</title>
1433 <p>Take care when constructing the target URL of the rule, considering
1434 the security impact from allowing the client influence over the set of
1435 URLs to which your server will act as a proxy. Ensure that the scheme
1436 and hostname part of the URL is either fixed or does not allow the
1437 client undue influence.</p>
1440 </directivesynopsis>
1443 <name>ProxyPassReverse</name>
1444 <description>Adjusts the URL in HTTP response headers sent from a reverse
1445 proxied server</description>
1446 <syntax>ProxyPassReverse [<var>path</var>] <var>url</var>
1447 [<var>interpolate</var>]</syntax>
1448 <contextlist><context>server config</context><context>virtual host</context>
1449 <context>directory</context>
1453 <p>This directive lets Apache httpd adjust the URL in the <code>Location</code>,
1454 <code>Content-Location</code> and <code>URI</code> headers on HTTP
1455 redirect responses. This is essential when Apache httpd is used as a
1456 reverse proxy (or gateway) to avoid bypassing the reverse proxy
1457 because of HTTP redirects on the backend servers which stay behind
1458 the reverse proxy.</p>
1460 <p>Only the HTTP response headers specifically mentioned above
1461 will be rewritten. Apache httpd will not rewrite other response
1462 headers, nor will it by default rewrite URL references inside HTML pages.
1463 This means that if the proxied content contains absolute URL
1464 references, they will bypass the proxy. To rewrite HTML content to
1465 match the proxy, you must load and enable <module>mod_proxy_html</module>.
1468 <p><var>path</var> is the name of a local virtual path; <var>url</var> is a
1469 partial URL for the remote server. These parameters are used the same way as
1470 for the <directive module="mod_proxy">ProxyPass</directive> directive.</p>
1472 <p>For example, suppose the local server has address
1473 <code>http://example.com/</code>; then</p>
1475 <highlight language="config">
1476 ProxyPass "/mirror/foo/" "http://backend.example.com/"
1477 ProxyPassReverse "/mirror/foo/" "http://backend.example.com/"
1478 ProxyPassReverseCookieDomain backend.example.com public.example.com
1479 ProxyPassReverseCookiePath "/" "/mirror/foo/"
1482 <p>will not only cause a local request for the
1483 <code>http://example.com/mirror/foo/bar</code> to be internally converted
1484 into a proxy request to <code>http://backend.example.com/bar</code>
1485 (the functionality which <code>ProxyPass</code> provides here).
1486 It also takes care of redirects which the server <code>backend.example.com</code> sends
1487 when redirecting <code>http://backend.example.com/bar</code> to
1488 <code>http://backend.example.com/quux</code> . Apache httpd adjusts this to
1489 <code>http://example.com/mirror/foo/quux</code> before forwarding the HTTP
1490 redirect response to the client. Note that the hostname used for
1491 constructing the URL is chosen in respect to the setting of the <directive
1492 module="core">UseCanonicalName</directive> directive.</p>
1494 <p>Note that this <directive>ProxyPassReverse</directive> directive can
1495 also be used in conjunction with the proxy feature
1496 (<code>RewriteRule ... [P]</code>) from <module>mod_rewrite</module>
1497 because it doesn't depend on a corresponding <directive module="mod_proxy"
1498 >ProxyPass</directive> directive.</p>
1500 <p>The optional <var>interpolate</var> keyword, used together with
1501 <directive>ProxyPassInterpolateEnv</directive>, enables interpolation
1502 of environment variables specified using the format <var>${VARNAME}</var>.
1503 Note that interpolation is not supported within the scheme portion of a
1506 <p>When used inside a <directive type="section" module="core"
1507 >Location</directive> section, the first argument is omitted and the local
1508 directory is obtained from the <directive type="section" module="core"
1509 >Location</directive>. The same occurs inside a <directive type="section"
1510 module="core">LocationMatch</directive> section, but will probably not work as
1511 intended, as ProxyPassReverse will interpret the regexp literally as a
1512 path; if needed in this situation, specify the ProxyPassReverse outside
1513 the section or in a separate <directive type="section" module="core"
1514 >Location</directive> section.</p>
1516 <p>This directive is not supported in <directive type="section" module="core"
1517 >Directory</directive> or <directive type="section" module="core"
1518 >Files</directive> sections.</p>
1520 </directivesynopsis>
1523 <name>ProxyPassReverseCookieDomain</name>
1524 <description>Adjusts the Domain string in Set-Cookie headers from a reverse-
1525 proxied server</description>
1526 <syntax>ProxyPassReverseCookieDomain <var>internal-domain</var>
1527 <var>public-domain</var> [<var>interpolate</var>]</syntax>
1528 <contextlist><context>server config</context><context>virtual host</context>
1529 <context>directory</context>
1532 <p>Usage is basically similar to
1533 <directive module="mod_proxy">ProxyPassReverse</directive>, but instead of
1534 rewriting headers that are a URL, this rewrites the <code>domain</code>
1535 string in <code>Set-Cookie</code> headers.</p>
1537 </directivesynopsis>
1541 <name>ProxyPassReverseCookiePath</name>
1542 <description>Adjusts the Path string in Set-Cookie headers from a reverse-
1543 proxied server</description>
1544 <syntax>ProxyPassReverseCookiePath <var>internal-path</var>
1545 <var>public-path</var> [<var>interpolate</var>]</syntax>
1546 <contextlist><context>server config</context><context>virtual host</context>
1547 <context>directory</context>
1551 Useful in conjunction with
1552 <directive module="mod_proxy">ProxyPassReverse</directive>
1553 in situations where backend URL paths are mapped to public paths on the
1554 reverse proxy. This directive rewrites the <code>path</code> string in
1555 <code>Set-Cookie</code> headers. If the beginning of the cookie path matches
1556 <var>internal-path</var>, the cookie path will be replaced with
1557 <var>public-path</var>.
1559 In the example given with
1560 <directive module="mod_proxy">ProxyPassReverse</directive>, the directive:
1562 <highlight language="config">
1563 ProxyPassReverseCookiePath "/" "/mirror/foo/"
1566 will rewrite a cookie with backend path <code>/</code> (or
1567 <code>/example</code> or, in fact, anything) to <code>/mirror/foo/</code>.
1570 </directivesynopsis>
1573 <name>ProxyBlock</name>
1574 <description>Disallow proxy requests to certain hosts</description>
1575 <syntax>ProxyBlock *|<var>hostname</var>|<var>partial-hostname</var> [<var>hostname</var>|<var>partial-hostname</var>]...</syntax>
1576 <contextlist><context>server config</context><context>virtual host</context>
1580 <p>The <directive>ProxyBlock</directive> directive can be used to
1581 block FTP or HTTP access to certain hosts via the proxy, based on
1582 a full or partial hostname match, or, if applicable, an IP address
1585 <p>Each of the arguments to the <directive>ProxyBlock</directive>
1586 directive can be either <code>*</code> or a alphanumeric string.
1587 At startup, the module will attempt to resolve every alphanumeric
1588 string from a DNS name to a set of IP addresses, but any DNS errors
1591 <p>If an asterisk "<code>*</code>" argument is specified,
1592 <module>mod_proxy</module> will deny access to all FTP or HTTP
1595 <p>Otherwise, for any request for an HTTP or FTP resource via the
1596 proxy, <module>mod_proxy</module> will check the hostname of the
1597 request URI against each specified string. If a partial string
1598 match is found, access is denied. If no matches against hostnames
1599 are found, and a remote (forward) proxy is configured using
1600 <directive>ProxyRemote</directive> or
1601 <directive>ProxyRemoteMatch</directive>, access is allowed. If no
1602 remote (forward) proxy is configured, the IP address of the
1603 hostname from the URI is compared against all resolved IP
1604 addresses determined at startup. Access is denied if any match is
1607 <p>Note that the DNS lookups may slow down the startup time of the
1610 <example><title>Example</title>
1611 <highlight language="config">
1612 ProxyBlock news.example.com auctions.example.com friends.example.com
1616 <p>Note that <code>example</code> would also be sufficient to match any
1619 <p>Hosts would also be matched if referenced by IP address.</p>
1621 <p>Note also that</p>
1623 <highlight language="config">
1627 <p>blocks connections to all sites.</p>
1629 </directivesynopsis>
1632 <name>ProxyReceiveBufferSize</name>
1633 <description>Network buffer size for proxied HTTP and FTP
1634 connections</description>
1635 <syntax>ProxyReceiveBufferSize <var>bytes</var></syntax>
1636 <default>ProxyReceiveBufferSize 0</default>
1637 <contextlist><context>server config</context><context>virtual host</context>
1641 <p>The <directive>ProxyReceiveBufferSize</directive> directive specifies an
1642 explicit (TCP/IP) network buffer size for proxied HTTP and FTP connections,
1643 for increased throughput. It has to be greater than <code>512</code> or set
1644 to <code>0</code> to indicate that the system's default buffer size should
1647 <example><title>Example</title>
1648 <highlight language="config">
1649 ProxyReceiveBufferSize 2048
1653 </directivesynopsis>
1656 <name>ProxyIOBufferSize</name>
1657 <description>Determine size of internal data throughput buffer</description>
1658 <syntax>ProxyIOBufferSize <var>bytes</var></syntax>
1659 <default>ProxyIOBufferSize 8192</default>
1660 <contextlist><context>server config</context><context>virtual host</context>
1664 <p>The <directive>ProxyIOBufferSize</directive> directive adjusts the size
1665 of the internal buffer which is used as a scratchpad for the data between
1666 input and output. The size must be at least <code>512</code>.</p>
1668 <p>In almost every case, there's no reason to change that value.</p>
1670 <p>If used with AJP, this directive sets the maximum AJP packet size in
1671 bytes. Values larger than 65536 are set to 65536. If you change it from
1672 the default, you must also change the <code>packetSize</code> attribute of
1673 your AJP connector on the Tomcat side! The attribute
1674 <code>packetSize</code> is only available in Tomcat <code>5.5.20+</code>
1675 and <code>6.0.2+</code></p>
1677 <p>Normally it is not necessary to change the maximum packet size.
1678 Problems with the default value have been reported when sending
1679 certificates or certificate chains.</p>
1682 </directivesynopsis>
1685 <name>ProxyMaxForwards</name>
1686 <description>Maximium number of proxies that a request can be forwarded
1687 through</description>
1688 <syntax>ProxyMaxForwards <var>number</var></syntax>
1689 <default>ProxyMaxForwards -1</default>
1690 <contextlist><context>server config</context><context>virtual host</context>
1694 <p>The <directive>ProxyMaxForwards</directive> directive specifies the
1695 maximum number of proxies through which a request may pass if there's no
1696 <code>Max-Forwards</code> header supplied with the request. This may
1697 be set to prevent infinite proxy loops or a DoS attack.</p>
1699 <example><title>Example</title>
1700 <highlight language="config">
1705 <p>Note that setting <directive>ProxyMaxForwards</directive> is a
1706 violation of the HTTP/1.1 protocol (RFC2616), which forbids a Proxy
1707 setting <code>Max-Forwards</code> if the Client didn't set it.
1708 Earlier Apache httpd versions would always set it. A negative
1709 <directive>ProxyMaxForwards</directive> value, including the
1710 default -1, gives you protocol-compliant behavior but may
1711 leave you open to loops.</p>
1713 </directivesynopsis>
1716 <name>NoProxy</name>
1717 <description>Hosts, domains, or networks that will be connected to
1718 directly</description>
1719 <syntax>NoProxy <var>host</var> [<var>host</var>] ...</syntax>
1720 <contextlist><context>server config</context><context>virtual host</context>
1724 <p>This directive is only useful for Apache httpd proxy servers within
1725 intranets. The <directive>NoProxy</directive> directive specifies a
1726 list of subnets, IP addresses, hosts and/or domains, separated by
1727 spaces. A request to a host which matches one or more of these is
1728 always served directly, without forwarding to the configured
1729 <directive module="mod_proxy">ProxyRemote</directive> proxy server(s).</p>
1731 <example><title>Example</title>
1732 <highlight language="config">
1733 ProxyRemote * http://firewall.example.com:81
1734 NoProxy .example.com 192.168.112.0/21
1738 <p>The <var>host</var> arguments to the <directive>NoProxy</directive>
1739 directive are one of the following type list:</p>
1742 <!-- ===================== Domain ======================= -->
1743 <dt><var><a name="domain" id="domain">Domain</a></var></dt>
1745 <p>A <dfn>Domain</dfn> is a partially qualified DNS domain name, preceded
1746 by a period. It represents a list of hosts which logically belong to the
1747 same DNS domain or zone (<em>i.e.</em>, the suffixes of the hostnames are
1748 all ending in <var>Domain</var>).</p>
1750 <example><title>Examples</title>
1754 <p>To distinguish <var>Domain</var>s from <var><a href="#hostname"
1755 >Hostname</a></var>s (both syntactically and semantically; a DNS domain can
1756 have a DNS A record, too!), <var>Domain</var>s are always written with a
1759 <note><title>Note</title>
1760 <p>Domain name comparisons are done without regard to the case, and
1761 <var>Domain</var>s are always assumed to be anchored in the root of the
1762 DNS tree; therefore, the two domains <code>.ExAmple.com</code> and
1763 <code>.example.com.</code> (note the trailing period) are considered
1764 equal. Since a domain comparison does not involve a DNS lookup, it is much
1765 more efficient than subnet comparison.</p>
1768 <!-- ===================== SubNet ======================= -->
1769 <dt><var><a name="subnet" id="subnet">SubNet</a></var></dt>
1771 <p>A <dfn>SubNet</dfn> is a partially qualified internet address in
1772 numeric (dotted quad) form, optionally followed by a slash and the netmask,
1773 specified as the number of significant bits in the <var>SubNet</var>. It is
1774 used to represent a subnet of hosts which can be reached over a common
1775 network interface. In the absence of the explicit net mask it is assumed
1776 that omitted (or zero valued) trailing digits specify the mask. (In this
1777 case, the netmask can only be multiples of 8 bits wide.) Examples:</p>
1780 <dt><code>192.168</code> or <code>192.168.0.0</code></dt>
1781 <dd>the subnet 192.168.0.0 with an implied netmask of 16 valid bits
1782 (sometimes used in the netmask form <code>255.255.0.0</code>)</dd>
1783 <dt><code>192.168.112.0/21</code></dt>
1784 <dd>the subnet <code>192.168.112.0/21</code> with a netmask of 21
1785 valid bits (also used in the form <code>255.255.248.0</code>)</dd>
1788 <p>As a degenerate case, a <em>SubNet</em> with 32 valid bits is the
1789 equivalent to an <var><a href="#ipaddr">IPAddr</a></var>, while a <var>SubNet</var> with zero
1790 valid bits (<em>e.g.</em>, 0.0.0.0/0) is the same as the constant
1791 <var>_Default_</var>, matching any IP address.</p></dd>
1793 <!-- ===================== IPAddr ======================= -->
1794 <dt><var><a name="ipaddr" id="ipaddr">IPAddr</a></var></dt>
1796 <p>A <dfn>IPAddr</dfn> represents a fully qualified internet address in
1797 numeric (dotted quad) form. Usually, this address represents a host, but
1798 there need not necessarily be a DNS domain name connected with the
1800 <example><title>Example</title>
1804 <note><title>Note</title>
1805 <p>An <var>IPAddr</var> does not need to be resolved by the DNS system, so
1806 it can result in more effective apache performance.</p>
1809 <!-- ===================== Hostname ======================= -->
1810 <dt><var><a name="hostname" id="hostname">Hostname</a></var></dt>
1812 <p>A <dfn>Hostname</dfn> is a fully qualified DNS domain name which can
1813 be resolved to one or more <var><a href="#ipaddr">IPAddrs</a></var> via the
1814 DNS domain name service. It represents a logical host (in contrast to
1815 <var><a href="#domain">Domain</a></var>s, see above) and must be resolvable
1816 to at least one <var><a href="#ipaddr">IPAddr</a></var> (or often to a list
1817 of hosts with different <var><a href="#ipaddr">IPAddr</a></var>s).</p>
1819 <example><title>Examples</title>
1820 prep.ai.example.edu<br />
1824 <note><title>Note</title>
1825 <p>In many situations, it is more effective to specify an <var><a
1826 href="#ipaddr">IPAddr</a></var> in place of a <var>Hostname</var> since a
1827 DNS lookup can be avoided. Name resolution in Apache httpd can take a remarkable
1828 deal of time when the connection to the name server uses a slow PPP
1830 <p><var>Hostname</var> comparisons are done without regard to the case,
1831 and <var>Hostname</var>s are always assumed to be anchored in the root
1832 of the DNS tree; therefore, the two hosts <code>WWW.ExAmple.com</code>
1833 and <code>www.example.com.</code> (note the trailing period) are
1834 considered equal.</p>
1838 <seealso><a href="../dns-caveats.html">DNS Issues</a></seealso>
1839 </directivesynopsis>
1842 <name>ProxyTimeout</name>
1843 <description>Network timeout for proxied requests</description>
1844 <syntax>ProxyTimeout <var>seconds</var></syntax>
1845 <default>Value of <directive module="core">Timeout</directive></default>
1846 <contextlist><context>server config</context><context>virtual host</context>
1850 <p>This directive allows a user to specifiy a timeout on proxy requests.
1851 This is useful when you have a slow/buggy appserver which hangs, and you
1852 would rather just return a timeout and fail gracefully instead of waiting
1853 however long it takes the server to return.</p>
1855 </directivesynopsis>
1858 <name>ProxyDomain</name>
1859 <description>Default domain name for proxied requests</description>
1860 <syntax>ProxyDomain <var>Domain</var></syntax>
1861 <contextlist><context>server config</context><context>virtual host</context>
1865 <p>This directive is only useful for Apache httpd proxy servers within
1866 intranets. The <directive>ProxyDomain</directive> directive specifies
1867 the default domain which the apache proxy server will belong to. If a
1868 request to a host without a domain name is encountered, a redirection
1869 response to the same host with the configured <var>Domain</var> appended
1870 will be generated.</p>
1872 <example><title>Example</title>
1873 <highlight language="config">
1874 ProxyRemote "*" "http://firewall.example.com:81"
1875 NoProxy ".example.com" "192.168.112.0/21"
1876 ProxyDomain ".example.com"
1880 </directivesynopsis>
1883 <name>ProxyVia</name>
1884 <description>Information provided in the <code>Via</code> HTTP response
1885 header for proxied requests</description>
1886 <syntax>ProxyVia On|Off|Full|Block</syntax>
1887 <default>ProxyVia Off</default>
1888 <contextlist><context>server config</context><context>virtual host</context>
1892 <p>This directive controls the use of the <code>Via:</code> HTTP
1893 header by the proxy. Its intended use is to control the flow of
1894 proxy requests along a chain of proxy servers. See <a
1895 href="http://www.ietf.org/rfc/rfc2616.txt">RFC 2616</a> (HTTP/1.1), section
1896 14.45 for an explanation of <code>Via:</code> header lines.</p>
1899 <li>If set to <code>Off</code>, which is the default, no special processing
1900 is performed. If a request or reply contains a <code>Via:</code> header,
1901 it is passed through unchanged.</li>
1903 <li>If set to <code>On</code>, each request and reply will get a
1904 <code>Via:</code> header line added for the current host.</li>
1906 <li>If set to <code>Full</code>, each generated <code>Via:</code> header
1907 line will additionally have the Apache httpd server version shown as a
1908 <code>Via:</code> comment field.</li>
1910 <li>If set to <code>Block</code>, every proxy request will have all its
1911 <code>Via:</code> header lines removed. No new <code>Via:</code> header will
1915 </directivesynopsis>
1918 <name>ProxyErrorOverride</name>
1919 <description>Override error pages for proxied content</description>
1920 <syntax>ProxyErrorOverride On|Off</syntax>
1921 <default>ProxyErrorOverride Off</default>
1922 <contextlist><context>server config</context><context>virtual host</context>
1923 <context>directory</context>
1927 <p>This directive is useful for reverse-proxy setups where you want to
1928 have a common look and feel on the error pages seen by the end user.
1929 This also allows for included files (via
1930 <module>mod_include</module>'s SSI) to get
1931 the error code and act accordingly. (Default behavior would display
1932 the error page of the proxied server. Turning this on shows the SSI
1935 <p>This directive does not affect the processing of informational (1xx),
1936 normal success (2xx), or redirect (3xx) responses.</p>
1938 </directivesynopsis>
1941 <name>ProxyPassInterpolateEnv</name>
1942 <description>Enable Environment Variable interpolation in Reverse Proxy configurations</description>
1943 <syntax>ProxyPassInterpolateEnv On|Off</syntax>
1944 <default>ProxyPassInterpolateEnv Off</default>
1945 <contextlist><context>server config</context>
1946 <context>virtual host</context>
1947 <context>directory</context>
1951 <p>This directive, together with the <var>interpolate</var> argument to
1952 <directive>ProxyPass</directive>, <directive>ProxyPassReverse</directive>,
1953 <directive>ProxyPassReverseCookieDomain</directive>, and
1954 <directive>ProxyPassReverseCookiePath</directive>,
1955 enables reverse proxies to be dynamically
1956 configured using environment variables which may be set by
1957 another module such as <module>mod_rewrite</module>.
1958 It affects the <directive>ProxyPass</directive>,
1959 <directive>ProxyPassReverse</directive>,
1960 <directive>ProxyPassReverseCookieDomain</directive>, and
1961 <directive>ProxyPassReverseCookiePath</directive> directives
1962 and causes them to substitute the value of an environment
1963 variable <code>varname</code> for the string <code>${varname}</code>
1964 in configuration directives if the <var>interpolate</var> option is set.</p>
1965 <p>Keep this turned off (for server performance) unless you need it!</p>
1967 </directivesynopsis>
1970 <name>ProxyStatus</name>
1971 <description>Show Proxy LoadBalancer status in mod_status</description>
1972 <syntax>ProxyStatus Off|On|Full</syntax>
1973 <default>ProxyStatus Off</default>
1974 <contextlist><context>server config</context>
1975 <context>virtual host</context>
1979 <p>This directive determines whether or not proxy
1980 loadbalancer status data is displayed via the <module>mod_status</module>
1981 server-status page.</p>
1982 <note><title>Note</title>
1983 <p><strong>Full</strong> is synonymous with <strong>On</strong></p>
1987 </directivesynopsis>
1990 <name>ProxyAddHeaders</name>
1991 <description>Add proxy information in X-Forwarded-* headers</description>
1992 <syntax>ProxyAddHeaders Off|On</syntax>
1993 <default>ProxyAddHeaders On</default>
1994 <contextlist><context>server config</context>
1995 <context>virtual host</context>
1996 <context>directory</context>
1998 <compatibility>Available in version 2.3.10 and later</compatibility>
2001 <p>This directive determines whether or not proxy related information should be passed to the
2002 backend server through X-Forwarded-For, X-Forwarded-Host and X-Forwarded-Server HTTP headers.</p>
2003 <note><title>Effectiveness</title>
2004 <p>This option is of use only for HTTP proxying, as handled by <module>mod_proxy_http</module>.</p>
2007 </directivesynopsis>
2010 <name>ProxySourceAddress</name>
2011 <description>Set local IP address for outgoing proxy connections</description>
2012 <syntax>ProxySourceAddress <var>address</var></syntax>
2013 <contextlist><context>server config</context>
2014 <context>virtual host</context>
2016 <compatibility>Available in version 2.3.9 and later</compatibility>
2019 <p>This directive allows to set a specific local address to bind to when connecting
2020 to a backend server.</p>
2022 </directivesynopsis>