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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_connect</module></seealso>
87 <seealso><module>mod_proxy_fcgi</module></seealso>
88 <seealso><module>mod_proxy_ftp</module></seealso>
89 <seealso><module>mod_proxy_http</module></seealso>
90 <seealso><module>mod_proxy_scgi</module></seealso>
91 <seealso><module>mod_proxy_wstunnel</module></seealso>
92 <seealso><module>mod_proxy_balancer</module></seealso>
93 <seealso><module>mod_ssl</module></seealso>
95 <section id="forwardreverse"><title>Forward Proxies and Reverse
96 Proxies/Gateways</title>
97 <p>Apache HTTP Server can be configured in both a <dfn>forward</dfn> and
98 <dfn>reverse</dfn> proxy (also known as <dfn>gateway</dfn>) mode.</p>
100 <p>An ordinary <dfn>forward proxy</dfn> is an intermediate
101 server that sits between the client and the <em>origin
102 server</em>. In order to get content from the origin server,
103 the client sends a request to the proxy naming the origin server
104 as the target and the proxy then requests the content from the
105 origin server and returns it to the client. The client must be
106 specially configured to use the forward proxy to access other
109 <p>A typical usage of a forward proxy is to provide Internet
110 access to internal clients that are otherwise restricted by a
111 firewall. The forward proxy can also use caching (as provided
112 by <module>mod_cache</module>) to reduce network usage.</p>
114 <p>The forward proxy is activated using the <directive
115 module="mod_proxy">ProxyRequests</directive> directive. Because
116 forward proxies allow clients to access arbitrary sites through
117 your server and to hide their true origin, it is essential that
118 you <a href="#access">secure your server</a> so that only
119 authorized clients can access the proxy before activating a
122 <p>A <dfn>reverse proxy</dfn> (or <dfn>gateway</dfn>), by
123 contrast, appears to the client just like an ordinary web
124 server. No special configuration on the client is necessary.
125 The client makes ordinary requests for content in the name-space
126 of the reverse proxy. The reverse proxy then decides where to
127 send those requests, and returns the content as if it was itself
130 <p>A typical usage of a reverse proxy is to provide Internet
131 users access to a server that is behind a firewall. Reverse
132 proxies can also be used to balance load among several back-end
133 servers, or to provide caching for a slower back-end server.
134 In addition, reverse proxies can be used simply to bring
135 several servers into the same URL space.</p>
137 <p>A reverse proxy is activated using the <directive
138 module="mod_proxy">ProxyPass</directive> directive or the
139 <code>[P]</code> flag to the <directive
140 module="mod_rewrite">RewriteRule</directive> directive. It is
141 <strong>not</strong> necessary to turn <directive
142 module="mod_proxy">ProxyRequests</directive> on in order to
143 configure a reverse proxy.</p>
144 </section> <!-- /forwardreverse -->
146 <section id="examples"><title>Basic Examples</title>
148 <p>The examples below are only a very basic idea to help you
149 get started. Please read the documentation on the individual
152 <p>In addition, if you wish to have caching enabled, consult
153 the documentation from <module>mod_cache</module>.</p>
155 <example><title>Reverse Proxy</title>
156 <highlight language="config">
157 ProxyPass /foo http://foo.example.com/bar
158 ProxyPassReverse /foo http://foo.example.com/bar
162 <example><title>Forward Proxy</title>
163 <highlight language="config">
168 Require host internal.example.com
172 </section> <!-- /examples -->
174 <section id="handler"><title>Access via Handler</title>
176 <p>You can also force a request to be handled as a reverse-proxy
177 request, by creating a suitable Handler pass-thru. For example,
178 the below will pass all PHP scripts to the specified
179 reverse-proxy FCGI server:
182 <example><title>Reverse Proxy PHP scripts</title>
183 <highlight language="config">
184 <FilesMatch \.php$>
185 SetHandler "proxy:unix:/path/to/app.sock|fcgi://localhost/"
189 </section> <!-- /handler -->
192 <section id="workers"><title>Workers</title>
193 <p>The proxy manages the configuration of origin servers and their
194 communication parameters in objects called <dfn>workers</dfn>.
195 There are two built-in workers, the default forward proxy worker and the
196 default reverse proxy worker. Additional workers can be configured
199 <p>The two default workers have a fixed configuration
200 and will be used if no other worker matches the request.
201 They do not use HTTP Keep-Alive or connection pooling.
202 The TCP connections to the origin server will instead be
203 opened and closed for each request.</p>
205 <p>Explicitly configured workers are identified by their URL.
206 They are usually created and configured using
207 <directive module="mod_proxy">ProxyPass</directive> or
208 <directive module="mod_proxy">ProxyPassMatch</directive> when used
209 for a reverse proxy:</p>
211 <highlight language="config">
212 ProxyPass /example http://backend.example.com connectiontimeout=5 timeout=30
215 <p>This will create a worker associated with the origin server URL
216 <code>http://backend.example.com</code> and using the given timeout
217 values. When used in a forward proxy, workers are usually defined
218 via the <directive module="mod_proxy">ProxySet</directive> directive:</p>
220 <highlight language="config">
221 ProxySet http://backend.example.com connectiontimeout=5 timeout=30
224 <p>or alternatively using <directive module="mod_proxy">Proxy</directive>
225 and <directive module="mod_proxy">ProxySet</directive>:</p>
227 <highlight language="config">
228 <Proxy http://backend.example.com>
229 ProxySet connectiontimeout=5 timeout=30
233 <p>Using explicitly configured workers in the forward mode is
234 not very common, because forward proxies usually communicate with many
235 different origin servers. Creating explicit workers for some of the
236 origin servers can still be useful, if they are used very often.
237 Explicitly configured workers have no concept of forward or reverse
238 proxying by themselves. They encapsulate a common concept of
239 communication with origin servers. A worker created by
240 <directive module="mod_proxy">ProxyPass</directive> for use in a
241 reverse proxy will be also used for forward proxy requests whenever
242 the URL to the origin server matches the worker URL and vice versa.</p>
244 <p>The URL identifying a direct worker is the URL of its
245 origin server including any path components given:</p>
247 <highlight language="config">
248 ProxyPass /examples http://backend.example.com/examples
249 ProxyPass /docs http://backend.example.com/docs
252 <p>This example defines two different workers, each using a separate
253 connection pool and configuration.</p>
255 <note type="warning"><title>Worker Sharing</title>
256 <p>Worker sharing happens if the worker URLs overlap, which occurs when
257 the URL of some worker is a leading substring of the URL of another
258 worker defined later in the configuration file. In the following example</p>
260 <highlight language="config">
261 ProxyPass /apps http://backend.example.com/ timeout=60
262 ProxyPass /examples http://backend.example.com/examples timeout=10
265 <p>the second worker isn't actually created. Instead the first
266 worker is used. The benefit is, that there is only one connection pool,
267 so connections are more often reused. Note that all configuration attributes
268 given explicitly for the later worker will be ignored. This will be logged
269 as a warning. In the above example the resulting timeout value
270 for the URL <code>/examples</code> will be <code>60</code> instead
271 of <code>10</code>!</p>
273 <p>If you want to avoid worker sharing, sort your worker definitions
274 by URL length, starting with the longest worker URLs. If you want to maximize
275 worker sharing use the reverse sort order. See also the related warning about
276 ordering <directive module="mod_proxy">ProxyPass</directive> directives.</p>
278 </note> <!-- /worker_sharing -->
280 <p>Explicitly configured workers come in two flavors:
281 <dfn>direct workers</dfn> and <dfn>(load) balancer workers</dfn>.
282 They support many important configuration attributes which are
283 described below in the <directive module="mod_proxy">ProxyPass</directive>
284 directive. The same attributes can also be set using
285 <directive module="mod_proxy">ProxySet</directive>.</p>
287 <p>The set of options available for a direct worker
288 depends on the protocol, which is specified in the origin server URL.
289 Available protocols include <code>ajp</code>, <code>fcgi</code>,
290 <code>ftp</code>, <code>http</code> and <code>scgi</code>.</p>
292 <p>Balancer workers are virtual workers that use direct workers known
293 as their members to actually handle the requests. Each balancer can
294 have multiple members. When it handles a request, it chooses a member
295 based on the configured load balancing algorithm.</p>
297 <p>A balancer worker is created if its worker URL uses
298 <code>balancer</code> as the protocol scheme.
299 The balancer URL uniquely identifies the balancer worker.
300 Members are added to a balancer using
301 <directive module="mod_proxy">BalancerMember</directive>.</p>
303 </section> <!-- /workers -->
305 <section id="access"><title>Controlling access to your proxy</title>
306 <p>You can control who can access your proxy via the <directive
307 module="mod_proxy" type="section">Proxy</directive> control block as in
308 the following example:</p>
310 <highlight language="config">
316 <p>For more information on access control directives, see
317 <module>mod_authz_host</module>.</p>
319 <p>Strictly limiting access is essential if you are using a
320 forward proxy (using the <directive
321 module="mod_proxy">ProxyRequests</directive> directive).
322 Otherwise, your server can be used by any client to access
323 arbitrary hosts while hiding his or her true identity. This is
324 dangerous both for your network and for the Internet at large.
325 When using a reverse proxy (using the <directive
326 module="mod_proxy">ProxyPass</directive> directive with
327 <code>ProxyRequests Off</code>), access control is less
328 critical because clients can only contact the hosts that you
329 have specifically configured.</p>
331 <p><strong>See Also</strong> the <a href="mod_proxy_http.html#env"
332 >Proxy-Chain-Auth</a> environment variable.</p>
334 </section> <!-- /access -->
336 <section id="startup"><title>Slow Startup</title>
337 <p>If you're using the <directive module="mod_proxy"
338 >ProxyBlock</directive> directive, hostnames' IP addresses are looked up
339 and cached during startup for later match test. This may take a few
340 seconds (or more) depending on the speed with which the hostname lookups
342 </section> <!-- /startup -->
344 <section id="intranet"><title>Intranet Proxy</title>
345 <p>An Apache httpd proxy server situated in an intranet needs to forward
346 external requests through the company's firewall (for this, configure
347 the <directive module="mod_proxy">ProxyRemote</directive> directive
348 to forward the respective <var>scheme</var> to the firewall proxy).
349 However, when it has to
350 access resources within the intranet, it can bypass the firewall when
351 accessing hosts. The <directive module="mod_proxy">NoProxy</directive>
352 directive is useful for specifying which hosts belong to the intranet and
353 should be accessed directly.</p>
355 <p>Users within an intranet tend to omit the local domain name from their
356 WWW requests, thus requesting "http://somehost/" instead of
357 <code>http://somehost.example.com/</code>. Some commercial proxy servers
358 let them get away with this and simply serve the request, implying a
359 configured local domain. When the <directive module="mod_proxy"
360 >ProxyDomain</directive> directive is used and the server is <a
361 href="#proxyrequests">configured for proxy service</a>, Apache httpd can return
362 a redirect response and send the client to the correct, fully qualified,
363 server address. This is the preferred method since the user's bookmark
364 files will then contain fully qualified hosts.</p>
365 </section> <!-- /intranet -->
367 <section id="envsettings"><title>Protocol Adjustments</title>
368 <p>For circumstances where <module>mod_proxy</module> is sending
369 requests to an origin server that doesn't properly implement
370 keepalives or HTTP/1.1, there are two <a
371 href="../env.html">environment variables</a> that can force the
372 request to use HTTP/1.0 with no keepalive. These are set via the
373 <directive module="mod_env">SetEnv</directive> directive.</p>
375 <p>These are the <code>force-proxy-request-1.0</code> and
376 <code>proxy-nokeepalive</code> notes.</p>
378 <highlight language="config">
379 <Location /buggyappserver/>
380 ProxyPass http://buggyappserver:7001/foo/
381 SetEnv force-proxy-request-1.0 1
382 SetEnv proxy-nokeepalive 1
386 </section> <!-- /envsettings -->
388 <section id="request-bodies"><title>Request Bodies</title>
390 <p>Some request methods such as POST include a request body.
391 The HTTP protocol requires that requests which include a body
392 either use chunked transfer encoding or send a
393 <code>Content-Length</code> request header. When passing these
394 requests on to the origin server, <module>mod_proxy_http</module>
395 will always attempt to send the <code>Content-Length</code>. But
396 if the body is large and the original request used chunked
397 encoding, then chunked encoding may also be used in the upstream
398 request. You can control this selection using <a
399 href="../env.html">environment variables</a>. Setting
400 <code>proxy-sendcl</code> ensures maximum compatibility with
401 upstream servers by always sending the
402 <code>Content-Length</code>, while setting
403 <code>proxy-sendchunked</code> minimizes resource usage by using
404 chunked encoding.</p>
406 <p>Under some circumstances, the server must spool request bodies
407 to disk to satisfy the requested handling of request bodies. For
408 example, this spooling will occur if the original body was sent with
409 chunked encoding (and is large), but the administrator has
410 asked for backend requests to be sent with Content-Length or as HTTP/1.0.
411 This spooling can also occur if the request body already has a
412 Content-Length header, but the server is configured to filter incoming
415 <p><directive module="core">LimitRequestBody</directive> only applies to
416 request bodies that the server will spool to disk</p>
418 </section> <!-- /request-bodies -->
420 <section id="x-headers"><title>Reverse Proxy Request Headers</title>
422 <p>When acting in a reverse-proxy mode (using the <directive
423 module="mod_proxy">ProxyPass</directive> directive, for example),
424 <module>mod_proxy_http</module> adds several request headers in
425 order to pass information to the origin server. These headers
429 <dt><code>X-Forwarded-For</code></dt>
430 <dd>The IP address of the client.</dd>
431 <dt><code>X-Forwarded-Host</code></dt>
432 <dd>The original host requested by the client in the <code>Host</code>
433 HTTP request header.</dd>
434 <dt><code>X-Forwarded-Server</code></dt>
435 <dd>The hostname of the proxy server.</dd>
438 <p>Be careful when using these headers on the origin server, since
439 they will contain more than one (comma-separated) value if the
440 original request already contained one of these headers. For
441 example, you can use <code>%{X-Forwarded-For}i</code> in the log
442 format string of the origin server to log the original clients IP
443 address, but you may get more than one address if the request
444 passes through several proxies.</p>
446 <p>See also the <directive
447 module="mod_proxy">ProxyPreserveHost</directive> and <directive
448 module="mod_proxy">ProxyVia</directive> directives, which control
449 other request headers.</p>
451 </section> <!--/x-headers -->
454 <directivesynopsis type="section">
456 <description>Container for directives applied to proxied resources</description>
457 <syntax><Proxy <var>wildcard-url</var>> ...</Proxy></syntax>
458 <contextlist><context>server config</context><context>virtual host</context>
462 <p>Directives placed in <directive type="section">Proxy</directive>
463 sections apply only to matching proxied content. Shell-style wildcards are
466 <p>For example, the following will allow only hosts in
467 <code>yournetwork.example.com</code> to access content via your proxy
470 <highlight language="config">
472 Require host yournetwork.example.com
476 <p>The following example will process all files in the <code>foo</code>
477 directory of <code>example.com</code> through the <code>INCLUDES</code>
478 filter when they are sent through the proxy server:</p>
480 <highlight language="config">
481 <Proxy http://example.com/foo/*>
482 SetOutputFilter INCLUDES
486 <note><title>Differences from the Location configuration section</title>
487 <p>A backend URL matches the configuration section if it begins with the
488 the <var>wildcard-url</var> string, even if the last path segment in the
489 directive only matches a prefix of the backend URL. For example,
490 <Proxy http://example.com/foo> matches all of
491 http://example.com/foo, http://example.com/foo/bar, and
492 http://example.com/foobar. The matching of the final URL differs
493 from the behavior of the <directive type="section" module="core"
494 >Location</directive> section, which for purposes of this note
495 treats the final path component as if it ended in a slash.</p>
496 <p>For more control over the matching, see <directive type="section"
497 >ProxyMatch</directive>.</p>
501 <seealso><directive type="section" module="mod_proxy">ProxyMatch</directive></seealso>
505 <name>ProxyBadHeader</name>
506 <description>Determines how to handle bad header lines in a
507 response</description>
508 <syntax>ProxyBadHeader IsError|Ignore|StartBody</syntax>
509 <default>ProxyBadHeader IsError</default>
510 <contextlist><context>server config</context><context>virtual host</context>
514 <p>The <directive>ProxyBadHeader</directive> directive determines the
515 behaviour of <module>mod_proxy</module> if it receives syntactically invalid
516 response header lines (<em>i.e.</em> containing no colon) from the origin
517 server. The following arguments are possible:</p>
520 <dt><code>IsError</code></dt>
521 <dd>Abort the request and end up with a 502 (Bad Gateway) response. This is
522 the default behaviour.</dd>
524 <dt><code>Ignore</code></dt>
525 <dd>Treat bad header lines as if they weren't sent.</dd>
527 <dt><code>StartBody</code></dt>
528 <dd>When receiving the first bad header line, finish reading the headers and
529 treat the remainder as body. This helps to work around buggy backend servers
530 which forget to insert an empty line between the headers and the body.</dd>
535 <directivesynopsis type="section">
536 <name>ProxyMatch</name>
537 <description>Container for directives applied to regular-expression-matched
538 proxied resources</description>
539 <syntax><ProxyMatch <var>regex</var>> ...</ProxyMatch></syntax>
540 <contextlist><context>server config</context><context>virtual host</context>
544 <p>The <directive type="section">ProxyMatch</directive> directive is
545 identical to the <directive module="mod_proxy"
546 type="section">Proxy</directive> directive, except it matches URLs
547 using <glossary ref="regex">regular expressions</glossary>.</p>
549 <p>From 2.5.0 onwards, named groups and backreferences are captured and
550 written to the environment with the corresponding name prefixed with
551 "MATCH_" and in upper case. This allows elements of URLs to be referenced
552 from within <a href="../expr.html">expressions</a> and modules like
553 <module>mod_rewrite</module>. In order to prevent confusion, numbered
554 (unnamed) backreferences are ignored. Use named groups instead.</p>
556 <highlight language="config">
557 <ProxyMatch ^http://(?<sitename>[^/]+)>
558 require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example
562 <seealso><directive type="section" module="mod_proxy">Proxy</directive></seealso>
566 <name>ProxyPreserveHost</name>
567 <description>Use incoming Host HTTP request header for proxy
568 request</description>
569 <syntax>ProxyPreserveHost On|Off</syntax>
570 <default>ProxyPreserveHost Off</default>
571 <contextlist><context>server config</context><context>virtual host</context>
572 <context>directory</context>
574 <compatibility>Usable in directory
575 context in 2.3.3 and later.</compatibility>
578 <p>When enabled, this option will pass the Host: line from the incoming
579 request to the proxied host, instead of the hostname specified in the
580 <directive>ProxyPass</directive> line.</p>
582 <p>This option should normally be turned <code>Off</code>. It is mostly
583 useful in special configurations like proxied mass name-based virtual
584 hosting, where the original Host header needs to be evaluated by the
590 <name>ProxyRequests</name>
591 <description>Enables forward (standard) proxy requests</description>
592 <syntax>ProxyRequests On|Off</syntax>
593 <default>ProxyRequests Off</default>
594 <contextlist><context>server config</context><context>virtual host</context>
598 <p>This allows or prevents Apache httpd from functioning as a forward proxy
599 server. (Setting ProxyRequests to <code>Off</code> does not disable use of
600 the <directive module="mod_proxy">ProxyPass</directive> directive.)</p>
602 <p>In a typical reverse proxy or gateway configuration, this
603 option should be set to
604 <code>Off</code>.</p>
606 <p>In order to get the functionality of proxying HTTP or FTP sites, you
607 need also <module>mod_proxy_http</module> or <module>mod_proxy_ftp</module>
608 (or both) present in the server.</p>
610 <p>In order to get the functionality of (forward) proxying HTTPS sites, you
611 need <module>mod_proxy_connect</module> enabled in the server.</p>
613 <note type="warning"><title>Warning</title>
614 <p>Do not enable proxying with <directive
615 module="mod_proxy">ProxyRequests</directive> until you have <a
616 href="#access">secured your server</a>. Open proxy servers are dangerous
617 both to your network and to the Internet at large.</p>
620 <seealso><a href="#forwardreverse">Forward and Reverse Proxies/Gateways</a></seealso>
624 <name>ProxyRemote</name>
625 <description>Remote proxy used to handle certain requests</description>
626 <syntax>ProxyRemote <var>match</var> <var>remote-server</var></syntax>
627 <contextlist><context>server config</context><context>virtual host</context>
631 <p>This defines remote proxies to this proxy. <var>match</var> is either the
632 name of a URL-scheme that the remote server supports, or a partial URL
633 for which the remote server should be used, or <code>*</code> to indicate
634 the server should be contacted for all requests. <var>remote-server</var> is
635 a partial URL for the remote server. Syntax:</p>
638 <dfn>remote-server</dfn> =
639 <var>scheme</var>://<var>hostname</var>[:<var>port</var>]
642 <p><var>scheme</var> is effectively the protocol that should be used to
643 communicate with the remote server; only <code>http</code> and <code>https</code>
644 are supported by this module. When using <code>https</code>, the requests
645 are forwarded through the remote proxy using the HTTP CONNECT method.</p>
647 <example><title>Example</title>
648 <highlight language="config">
649 ProxyRemote http://goodguys.example.com/ http://mirrorguys.example.com:8000
650 ProxyRemote * http://cleverproxy.localdomain
651 ProxyRemote ftp http://ftpproxy.mydomain:8080
655 <p>In the last example, the proxy will forward FTP requests, encapsulated
656 as yet another HTTP proxy request, to another proxy which can handle
659 <p>This option also supports reverse proxy configuration - a backend
660 webserver can be embedded within a virtualhost URL space even if that
661 server is hidden by another forward proxy.</p>
666 <name>ProxyRemoteMatch</name>
667 <description>Remote proxy used to handle requests matched by regular
668 expressions</description>
669 <syntax>ProxyRemoteMatch <var>regex</var> <var>remote-server</var></syntax>
670 <contextlist><context>server config</context><context>virtual host</context>
674 <p>The <directive>ProxyRemoteMatch</directive> is identical to the
675 <directive module="mod_proxy">ProxyRemote</directive> directive, except the
676 first argument is a <glossary ref="regex">regular expression</glossary>
677 match against the requested URL.</p>
682 <name>BalancerGrowth</name>
683 <description>Number of additional Balancers that can be added Post-configuration</description>
684 <syntax>BalancerGrowth <var>#</var></syntax>
685 <default>BalancerGrowth 5</default>
686 <contextlist><context>server config</context><context>virtual host</context></contextlist>
687 <compatibility>BalancerGrowth is only available in Apache HTTP Server 2.3.13
688 and later.</compatibility>
690 <p>This directive allows for growth potential in the number of
691 Balancers available for a virtualhost in addition to the
692 number pre-configured. It only takes effect if there is at
693 least 1 pre-configured Balancer.</p>
698 <name>BalancerPersist</name>
699 <description>Attempt to persist changes made by the Balancer Manager across restarts.</description>
700 <syntax>BalancerPersist On|Off</syntax>
701 <default>BalancerPersist Off</default>
702 <contextlist><context>server config</context><context>virtual host</context></contextlist>
703 <compatibility>BalancerPersist is only available in Apache HTTP Server 2.4.4 and later.</compatibility>
705 <p>This directive will cause the shared memory storage associated
706 with the balancers and balancer members to be persisted across
707 restarts. This allows these local changes to not be lost during the
708 normal restart/graceful state transitions.</p>
713 <name>ProxyPassInherit</name>
714 <description>Inherit ProxyPass directives defined from the main server</description>
715 <syntax>ProxyPassInherit On|Off</syntax>
716 <default>ProxyPassInherit On</default>
717 <contextlist><context>server config</context><context>virtual host</context></contextlist>
718 <compatibility>ProxyPassInherit is only available in Apache HTTP Server 2.5.0 and later.
719 and later.</compatibility>
721 <p>This directive will cause the current server/vhost to "inherit"
722 <directive module="mod_proxy">ProxyPass</directive>
723 directives defined in the main server. This can cause issues and
724 inconsistent behavior if using the Balancer Manager for dynamic changes
725 and so should be disabled if using that feature.</p>
726 <p>The setting in the global server defines the default for all vhosts.</p>
727 <p>Disabling ProxyPassInherit also disables <directive module="mod_proxy">BalancerInherit</directive>.</p>
732 <name>BalancerInherit</name>
733 <description>Inherit proxy Balancers/Workers defined from the main server</description>
734 <syntax>BalancerInherit On|Off</syntax>
735 <default>BalancerInherit On</default>
736 <contextlist><context>server config</context><context>virtual host</context></contextlist>
737 <compatibility>BalancerInherit is only available in Apache HTTP Server 2.4.5 and later.</compatibility>
739 <p>This directive will cause the current server/vhost to "inherit"
740 Balancers and Workers defined in the main server. This can cause issues and
741 inconsistent behavior if using the Balancer Manager for dynamic changes
742 and so should be disabled if using that feature.</p>
743 <p>The setting in the global server defines the default for all vhosts.</p>
744 <p>Disabling <directive module="mod_proxy">ProxyPassInherit</directive> also disables BalancerInherit.</p>
749 <name>BalancerMember</name>
750 <description>Add a member to a load balancing group</description>
751 <syntax>BalancerMember [<var>balancerurl</var>] <var>url</var> [<var
752 >key=value [key=value ...]]</var></syntax>
753 <contextlist><context>directory</context>
756 <p>This directive adds a member to a load balancing group. It could be used
757 within a <code><Proxy <var>balancer://</var>...></code> container
758 directive, and can take any of the key value pair parameters available to
759 <directive module="mod_proxy">ProxyPass</directive> directives.</p>
760 <p>One additional parameter is available only to <directive
761 module="mod_proxy">BalancerMember</directive> directives:
762 <var>loadfactor</var>. This is the member load factor - a number between 1
763 (default) and 100, which defines the weighted load to be applied to the
764 member in question.</p>
765 <p>The balancerurl is only needed when not in <code><Proxy <var>balancer://</var>...></code>
766 container directive. It corresponds to the url of a balancer defined in
767 <directive module="mod_proxy">ProxyPass</directive> directive.</p>
768 <p>The path component of the balancer URL in any
769 <code><Proxy <var>balancer://</var>...></code> container directive
771 <p>Trailing slashes should typically be removed from the URL of a
772 <code>BalancerMember</code>.</p>
777 <name>ProxySet</name>
778 <description>Set various Proxy balancer or member parameters</description>
779 <syntax>ProxySet <var>url</var> <var>key=value [key=value ...]</var></syntax>
780 <contextlist><context>directory</context>
783 <p>This directive is used as an alternate method of setting any of the
784 parameters available to Proxy balancers and workers normally done via the
785 <directive module="mod_proxy">ProxyPass</directive> directive. If used
786 within a <code><Proxy <var>balancer url|worker url</var>></code>
787 container directive, the <var>url</var> argument is not required. As a side
788 effect the respective balancer or worker gets created. This can be useful
789 when doing reverse proxying via a
790 <directive module="mod_rewrite">RewriteRule</directive> instead of a
791 <directive module="mod_proxy">ProxyPass</directive> directive.</p>
794 <highlight language="config">
795 <Proxy balancer://hotcluster>
796 BalancerMember http://www2.example.com:8080 loadfactor=1
797 BalancerMember http://www3.example.com:8080 loadfactor=2
798 ProxySet lbmethod=bytraffic
803 <highlight language="config">
804 <Proxy http://backend>
805 ProxySet keepalive=On
809 <highlight language="config">
810 ProxySet balancer://foo lbmethod=bytraffic timeout=15
813 <highlight language="config">
814 ProxySet ajp://backend:7001 timeout=15
817 <note type="warning"><title>Warning</title>
818 <p>Keep in mind that the same parameter key can have a different meaning
819 depending whether it is applied to a balancer or a worker as shown by the two
820 examples above regarding timeout.</p>
827 <name>ProxyPass</name>
828 <description>Maps remote servers into the local server URL-space</description>
829 <syntax>ProxyPass [<var>path</var>] !|<var>url</var> [<var>key=value</var>
830 <var>[key=value</var> ...]] [nocanon] [interpolate] [noquery]</syntax>
831 <contextlist><context>server config</context><context>virtual host</context>
832 <context>directory</context>
836 <p>This directive allows remote servers to be mapped into the
837 space of the local server; the local server does not act as a
838 proxy in the conventional sense, but appears to be a mirror of the
839 remote server. The local server is often called a <dfn>reverse
840 proxy</dfn> or <dfn>gateway</dfn>. The <var>path</var> is the name of
841 a local virtual path; <var>url</var> is a partial URL for the
842 remote server and cannot include a query string.</p>
844 <note><strong>Note: </strong>This directive cannot be used within a
845 <code><Directory></code> context.</note>
847 <note type="warning">The <directive
848 module="mod_proxy">ProxyRequests</directive> directive should
849 usually be set <strong>off</strong> when using
850 <directive>ProxyPass</directive>.</note>
852 <p>Support for using a Unix Domain Socket is available by using a url target
853 which prepends <code>unix:/path/lis.sock|</code>. For example, to proxy
854 HTTP and target the UDS at /home/www/socket you would use
855 <code>unix:/home/www.socket|http://localhost/whatever/</code>. Since
856 the socket is local, the hostname used (in this case <code>localhost</code>)
857 is moot, but it is passed as the Host: header value of the request.</p>
859 <note><strong>Note:</strong> The path associated with the <code>unix:</code>
860 URL is <directive>DefaultRuntimeDir</directive> aware.</note>
862 <note><strong>Note:</strong> <directive>RewriteRule</directive> requires
863 the <code>[P,NE]</code> option to prevent the <code>'|'</code> character
864 from being escaped.</note>
866 <p>Suppose the local server has address <code>http://example.com/</code>;
869 <highlight language="config">
870 <Location /mirror/foo/>
871 ProxyPass http://backend.example.com/
875 <p>will cause a local request for
876 <code>http://example.com/mirror/foo/bar</code> to be internally converted
877 into a proxy request to <code>http://backend.example.com/bar</code>.</p>
879 <p>The following alternative syntax is possible, however it can carry a
880 performance penalty when present in very large numbers. The advantage of
881 the below syntax is that it allows for dynamic control via the
882 <a href="mod_proxy_balancer.html#balancer_manager">Balancer Manager</a> interface:</p>
884 <highlight language="config">
885 ProxyPass /mirror/foo/ http://backend.example.com/
888 <note type="warning">
889 <p>If the first argument ends with a trailing <strong>/</strong>, the second
890 argument should also end with a trailing <strong>/</strong> and vice
891 versa. Otherwise the resulting requests to the backend may miss some
892 needed slashes and do not deliver the expected results.
896 <p>The <code>!</code> directive is useful in situations where you don't want
897 to reverse-proxy a subdirectory, <em>e.g.</em></p>
899 <highlight language="config">
900 <Location /mirror/foo/>
901 ProxyPass http://backend.example.com/
903 <Location /mirror/foo/i>
908 <highlight language="config">
909 ProxyPass /mirror/foo/i !
910 ProxyPass /mirror/foo http://backend.example.com
913 <p>will proxy all requests to <code>/mirror/foo</code> to
914 <code>backend.example.com</code> <em>except</em> requests made to
915 <code>/mirror/foo/i</code>.</p>
917 <note type="warning"><title>Ordering ProxyPass Directives</title>
918 <p>The configured <directive module="mod_proxy">ProxyPass</directive>
919 and <directive module="mod_proxy">ProxyPassMatch</directive>
920 rules are checked in the order of configuration. The first rule that
921 matches wins. So usually you should sort conflicting
922 <directive module="mod_proxy">ProxyPass</directive> rules starting with the
923 longest URLs first. Otherwise later rules for longer URLS will be hidden
924 by any earlier rule which uses a leading substring of the URL. Note that
925 there is some relation with worker sharing. In contrast, only one
926 <directive module="mod_proxy">ProxyPass</directive> directive can be placed
927 in a <directive module="core">Location</directive> block, and the most
928 specific location will take precedence.</p>
930 <p>For the same reasons exclusions must come <em>before</em> the
931 general <directive>ProxyPass</directive> directives.</p>
933 </note> <!-- /ordering_proxypass -->
935 <p>In Apache HTTP Server 2.1 and later, mod_proxy supports pooled
936 connections to a backend server. Connections created on demand
937 can be retained in a pool for future use. Limits on the pool size
938 and other settings can be coded on
939 the <directive>ProxyPass</directive> directive
940 using <code>key=value</code> parameters, described in the table
943 <p>By default, mod_proxy will allow and retain the maximum number of
944 connections that could be used simultaneously by that web server child
945 process. Use the <code>max</code> parameter to reduce the number from
946 the default. Use the <code>ttl</code> parameter to set an optional
947 time to live; connections which have been unused for at least
948 <code>ttl</code> seconds will be closed. <code>ttl</code> can be used
949 to avoid using a connection which is subject to closing because of the
950 backend server's keep-alive timeout.</p>
952 <p>The pool of connections is maintained per web server child
953 process, and <code>max</code> and other settings are not coordinated
954 among all child processes, except when only one child process is allowed
955 by configuration or MPM design.</p>
957 <example><title>Example</title>
958 <highlight language="config">
959 ProxyPass /example http://backend.example.com max=20 ttl=120 retry=300
963 <table border="2"><tr><th>BalancerMember parameters</th></tr></table>
965 <tr><th>Parameter</th>
967 <th>Description</th></tr>
970 <td>Minimum number of connection pool entries, unrelated to the
971 actual number of connections. This only needs to be modified from the
972 default for special circumstances where heap memory associated with the
973 backend connections should be preallocated or retained.</td></tr>
976 <td>Maximum number of connections that will be allowed to the
977 backend server. The default for this limit is the number of threads
978 per process in the active MPM. In the Prefork MPM, this is always 1,
979 while with other MPMs it is controlled by the
980 <directive>ThreadsPerChild</directive> directive.</td></tr>
983 <td>Retained connection pool entries above this limit are freed
984 during certain operations if they have been unused for longer than
985 the time to live, controlled by the <code>ttl</code> parameter. If
986 the connection pool entry has an associated connection, it will be
987 closed. This only needs to be modified from the default for special
988 circumstances where connection pool entries and any associated
989 connections which have exceeded the time to live need to be freed or
990 closed more aggressively.</td></tr>
993 <td>If set this will be the maximum time to wait for a free
994 connection in the connection pool, in milliseconds. If there are no free
995 connections in the pool the Apache httpd will return <code>SERVER_BUSY</code>
996 status to the client.
998 <tr><td>connectiontimeout</td>
1000 <td>Connect timeout in seconds.
1001 The number of seconds Apache httpd waits for the creation of a connection to
1002 the backend to complete. By adding a postfix of ms the timeout can be
1003 also set in milliseconds.
1005 <tr><td>disablereuse</td>
1007 <td>This parameter should be used when you want to force mod_proxy
1008 to immediately close a connection to the backend after being used, and
1009 thus, disable its persistent connection and pool for that backend.
1010 This helps in various situations where a firewall between Apache
1012 the backend server (regardless of protocol) tends to silently
1013 drop connections or when backends themselves may be under round-
1014 robin DNS. To disable connection pooling reuse,
1015 set this property value to <code>On</code>.
1017 <tr><td>flushpackets</td>
1019 <td>Determines whether the proxy module will auto-flush the output
1020 brigade after each "chunk" of data. 'off' means that it will flush
1021 only when needed, 'on' means after each chunk is sent and
1022 'auto' means poll/wait for a period of time and flush if
1023 no input has been received for 'flushwait' milliseconds.
1024 Currently this is in effect only for AJP.
1026 <tr><td>flushwait</td>
1028 <td>The time to wait for additional input, in milliseconds, before
1029 flushing the output brigade if 'flushpackets' is 'auto'.
1031 <tr><td>iobuffersize</td>
1033 <td>Adjusts the size of the internal scratchpad IO buffer. This allows you
1034 to override the <directive>ProxyIOBufferSize</directive> for a specific worker.
1035 This must be at least 512 or set to 0 for the system default of 8192.
1037 <tr><td>keepalive</td>
1039 <td><p>This parameter should be used when you have a firewall between your
1040 Apache httpd and the backend server, who tend to drop inactive connections.
1041 This flag will tell the Operating System to send <code>KEEP_ALIVE</code>
1042 messages on inactive connections and thus prevent the firewall to drop the connection.
1043 To enable keepalive set this property value to <code>On</code>. </p>
1044 <p>The frequency of initial and subsequent TCP keepalive probes
1045 depends on global OS settings, and may be as high as 2 hours. To be useful,
1046 the frequency configured in the OS must be smaller than the threshold used
1047 by the firewall.</p>
1051 <td>Sets the load balancer cluster set that the worker is a member
1052 of. The load balancer will try all members of a lower numbered
1053 lbset before trying higher numbered ones.
1057 <td>Ping property tells the webserver to "test" the connection to
1058 the backend before forwarding the request. For negative values
1059 the test is a simple socket check, for positive values it's
1060 a more functional check, dependent upon the protocol. For AJP, it causes
1061 <module>mod_proxy_ajp</module>to send a <code>CPING</code>
1062 request on the ajp13 connection (implemented on Tomcat 3.3.2+, 4.1.28+
1063 and 5.0.13+). For HTTP, it causes <module>mod_proxy_http</module>
1064 to send a <code>100-Continue</code> to the backend (only valid for
1065 HTTP/1.1 - for non HTTP/1.1 backends, this property has no
1066 effect). In both cases the parameter is the delay in seconds to wait
1068 This feature has been added to avoid problems with hung and
1070 This will increase the network traffic during the normal operation
1071 which could be an issue, but it will lower the
1072 traffic in case some of the cluster nodes are down or busy.
1073 By adding a postfix of ms the delay can be also set in
1076 <tr><td>receivebuffersize</td>
1078 <td>Adjusts the size of the explicit (TCP/IP) network buffer size for
1079 proxied connections. This allows you to override the
1080 <directive>ProxyReceiveBufferSize</directive> for a specific worker.
1081 This must be at least 512 or set to 0 for the system default.
1083 <tr><td>redirect</td>
1085 <td>Redirection Route of the worker. This value is usually
1086 set dynamically to enable safe removal of the node from
1087 the cluster. If set all requests without session id will be
1088 redirected to the BalancerMember that has route parameter
1089 equal as this value.
1093 <td>Connection pool worker retry timeout in seconds.
1094 If the connection pool worker to the backend server is in the error state,
1095 Apache httpd will not forward any requests to that server until the timeout
1096 expires. This enables to shut down the backend server for maintenance,
1097 and bring it back online later. A value of 0 means always retry workers
1098 in an error state with no timeout.
1102 <td>Route of the worker when used inside load balancer.
1103 The route is a value appended to session id.
1107 <td>Single letter value defining the initial status of
1110 <tr><td>D: Worker is disabled and will not accept any requests.</td></tr>
1111 <tr><td>S: Worker is administratively stopped.</td></tr>
1112 <tr><td>I: Worker is in ignore-errors mode, and will always be considered available.</td></tr>
1113 <tr><td>H: Worker is in hot-standby mode and will only be used if no other
1114 viable workers are available.</td></tr>
1115 <tr><td>E: Worker is in an error state.</td></tr>
1116 <tr><td>N: Worker is in drain mode, and will only accept existing sticky sessions
1117 destined for itself and ignore all other requests.</td></tr>
1119 can be set (which is the default) by prepending with '+' or
1120 cleared by prepending with '-'.
1121 Thus, a setting of 'S-E' sets this worker to Stopped and
1122 clears the in-error flag.
1124 <tr><td>timeout</td>
1125 <td><directive module="mod_proxy">ProxyTimeout</directive></td>
1126 <td>Connection timeout in seconds.
1127 The number of seconds Apache httpd waits for data sent by / to the backend.
1131 <td>Time to live for inactive connections and associated connection
1132 pool entries, in seconds. Once reaching this limit, a
1133 connection will not be used again; it will be closed at some
1139 <p>If the Proxy directive scheme starts with the
1140 <code>balancer://</code> (eg: <code>balancer://cluster</code>,
1141 any path information is ignored) then a virtual worker that does not really
1142 communicate with the backend server will be created. Instead it is responsible
1143 for the management of several "real" workers. In that case the special set of
1144 parameters can be add to this virtual worker. See <module>mod_proxy_balancer</module>
1145 for more information about how the balancer works.
1147 <table border="2"><tr><th>Balancer parameters</th></tr></table>
1149 <tr><th>Parameter</th>
1151 <th>Description</th></tr>
1152 <tr><td>lbmethod</td>
1154 <td>Balancer load-balance method. Select the load-balancing scheduler
1155 method to use. Either <code>byrequests</code>, to perform weighted
1156 request counting, <code>bytraffic</code>, to perform weighted
1157 traffic byte count balancing, or <code>bybusyness</code>, to perform
1158 pending request balancing. Default is <code>byrequests</code>.
1160 <tr><td>maxattempts</td>
1161 <td>One less than the number of workers, or 1 with a single worker.</td>
1162 <td>Maximum number of failover attempts before giving up.
1164 <tr><td>nofailover</td>
1166 <td>If set to <code>On</code> the session will break if the worker is in
1167 error state or disabled. Set this value to On if backend servers do not
1168 support session replication.
1170 <tr><td>stickysession</td>
1172 <td>Balancer sticky session name. The value is usually set to something
1173 like <code>JSESSIONID</code> or <code>PHPSESSIONID</code>,
1174 and it depends on the backend application server that support sessions.
1175 If the backend application server uses different name for cookies
1176 and url encoded id (like servlet containers) use | to to separate them.
1177 The first part is for the cookie the second for the path.<br />
1178 Available in Apache HTTP Server 2.4.4 and later.
1180 <tr><td>stickysessionsep</td>
1182 <td>Sets the separation symbol in the session cookie. Some backend application servers
1183 do not use the '.' as the symbol. For example the Oracle Weblogic server uses
1184 '!'. The correct symbol can be set using this option. The setting of 'Off'
1185 signifies that no symbol is used.
1187 <tr><td>scolonpathdelim</td>
1189 <td>If set to <code>On</code> the semi-colon character ';' will be
1190 used as an additional sticky session path delimiter/separator. This
1191 is mainly used to emulate mod_jk's behavior when dealing with paths such
1192 as <code>JSESSIONID=6736bcf34;foo=aabfa</code>
1194 <tr><td>timeout</td>
1196 <td>Balancer timeout in seconds. If set this will be the maximum time
1197 to wait for a free worker. Default is not to wait.
1199 <tr><td>failonstatus</td>
1201 <td>A single or comma-separated list of HTTP status codes. If set this will
1202 force the worker into error state when the backend returns any status code
1203 in the list. Worker recovery behaves the same as other worker errors.
1205 <tr><td>failontimeout</td>
1207 <td>If set, an IO read timeout after a request is sent to the backend will
1208 force the worker into error state. Worker recovery behaves the same as other
1209 worker errors.<br />
1210 Available in Apache HTTP Server 2.4.5 and later.
1213 <td><auto></td>
1214 <td>The protective nonce used in the <code>balancer-manager</code> application page.
1215 The default is to use an automatically determined UUID-based
1216 nonce, to provide for further protection for the page. If set,
1217 then the nonce is set to that value. A setting of <code>None</code>
1218 disables all nonce checking.
1219 <note><title>Note</title>
1220 <p>In addition to the nonce, the <code>balancer-manager</code> page
1221 should be protected via an ACL.</p>
1226 <td>Number of additional BalancerMembers to allow to be added
1227 to this balancer in addition to those defined at configuration.
1229 <tr><td>forcerecovery</td>
1231 <td>Force the immediate recovery of all workers without considering the
1232 retry parameter of the workers if all workers of a balancer are
1233 in error state. There might be cases where an already overloaded backend
1234 can get into deeper trouble if the recovery of all workers is enforced
1235 without considering the retry parameter of each worker. In this case
1236 set to <code>Off</code>.<br />
1237 Available in Apache HTTP Server 2.4.2 and later.
1241 <p>A sample balancer setup</p>
1242 <highlight language="config">
1243 ProxyPass /special-area http://special.example.com smax=5 max=10
1244 ProxyPass / balancer://mycluster/ stickysession=JSESSIONID|jsessionid nofailover=On
1245 <Proxy balancer://mycluster>
1246 BalancerMember ajp://1.2.3.4:8009
1247 BalancerMember ajp://1.2.3.5:8009 loadfactor=20
1248 # Less powerful server, don't send as many requests there,
1249 BalancerMember ajp://1.2.3.6:8009 loadfactor=5
1253 <p>Setting up a hot-standby, that will only be used if no other
1254 members are available</p>
1255 <highlight language="config">
1256 ProxyPass / balancer://hotcluster/
1257 <Proxy balancer://hotcluster>
1258 BalancerMember ajp://1.2.3.4:8009 loadfactor=1
1259 BalancerMember ajp://1.2.3.5:8009 loadfactor=2
1260 # The server below is on hot standby
1261 BalancerMember ajp://1.2.3.6:8009 status=+H
1262 ProxySet lbmethod=bytraffic
1266 <p>Normally, mod_proxy will canonicalise ProxyPassed URLs.
1267 But this may be incompatible with some backends, particularly those
1268 that make use of <var>PATH_INFO</var>. The optional <var>nocanon</var>
1269 keyword suppresses this, and passes the URL path "raw" to the
1270 backend. Note that may affect the security of your backend, as it
1271 removes the normal limited protection against URL-based attacks
1272 provided by the proxy.</p>
1274 <p>Normally, mod_proxy will include the query string when
1275 generating the <var>SCRIPT_FILENAME</var> environment variable.
1276 The optional <var>noquery</var> keyword (available in
1277 httpd 2.4.1 and later) prevents this.</p>
1279 <p>When used inside a <directive type="section" module="core"
1280 >Location</directive> section, the first argument is omitted and the local
1281 directory is obtained from the <directive type="section" module="core"
1282 >Location</directive>. The same will occur inside a
1283 <directive type="section" module="core">LocationMatch</directive> section,
1284 however ProxyPass does not interpret the regexp as such, so it is necessary
1285 to use <directive>ProxyPassMatch</directive> in this situation instead.</p>
1287 <p>This directive is not supported in <directive type="section" module="core"
1288 >Directory</directive> or <directive type="section" module="core"
1289 >Files</directive> sections.</p>
1291 <p>If you require a more flexible reverse-proxy configuration, see the
1292 <directive module="mod_rewrite">RewriteRule</directive> directive with the
1293 <code>[P]</code> flag.</p>
1295 <p>The optional <var>interpolate</var> keyword, in combination with
1296 <directive>ProxyPassInterpolateEnv</directive> causes the ProxyPass
1297 to interpolate environment variables, using the syntax
1298 <var>${VARNAME}</var>. Note that many of the standard CGI-derived
1299 environment variables will not exist when this interpolation happens,
1300 so you may still have to resort to <module>mod_rewrite</module>
1301 for complex rules. Also note that interpolation is not supported
1302 within the scheme portion of a URL. Dynamic determination of the
1303 scheme can be accomplished with <module>mod_rewrite</module> as in the
1304 following example.</p>
1306 <highlight language="config">
1309 RewriteCond %{HTTPS} =off
1310 RewriteRule . - [E=protocol:http]
1311 RewriteCond %{HTTPS} =on
1312 RewriteRule . - [E=protocol:https]
1314 RewriteRule ^/mirror/foo/(.*) %{ENV:protocol}://backend.example.com/$1 [P]
1315 ProxyPassReverse /mirror/foo/ http://backend.example.com/
1316 ProxyPassReverse /mirror/foo/ https://backend.example.com/
1319 </directivesynopsis>
1322 <name>ProxyPassMatch</name>
1323 <description>Maps remote servers into the local server URL-space using regular expressions</description>
1324 <syntax>ProxyPassMatch [<var>regex</var>] !|<var>url</var> [<var>key=value</var>
1325 <var>[key=value</var> ...]]</syntax>
1326 <contextlist><context>server config</context><context>virtual host</context>
1327 <context>directory</context>
1331 <p>This directive is equivalent to <directive module="mod_proxy">ProxyPass</directive>,
1332 but makes use of regular expressions, instead of simple prefix matching. The
1333 supplied regular expression is matched against the <var>url</var>, and if it
1334 matches, the server will substitute any parenthesized matches into the given
1335 string and use it as a new <var>url</var>.</p>
1337 <note><strong>Note: </strong>This directive cannot be used within a
1338 <code><Directory></code> context.</note>
1340 <p>Suppose the local server has address <code>http://example.com/</code>;
1343 <highlight language="config">
1344 ProxyPassMatch ^(/.*\.gif)$ http://backend.example.com$1
1347 <p>will cause a local request for
1348 <code>http://example.com/foo/bar.gif</code> to be internally converted
1349 into a proxy request to <code>http://backend.example.com/foo/bar.gif</code>.</p>
1350 <note><title>Note</title>
1351 <p>The URL argument must be parsable as a URL <em>before</em> regexp
1352 substitutions (as well as after). This limits the matches you can use.
1353 For instance, if we had used</p>
1354 <highlight language="config">
1355 ProxyPassMatch ^(/.*\.gif)$ http://backend.example.com:8000$1
1357 <p>in our previous example, it would fail with a syntax error
1358 at server startup. This is a bug (PR 46665 in the ASF bugzilla),
1359 and the workaround is to reformulate the match:</p>
1360 <highlight language="config">
1361 ProxyPassMatch ^/(.*\.gif)$ http://backend.example.com:8000/$1
1364 <p>The <code>!</code> directive is useful in situations where you don't want
1365 to reverse-proxy a subdirectory.</p>
1367 <p>When used inside a <directive type="section" module="core"
1368 >LocationMatch</directive> section, the first argument is omitted and the
1369 regexp is obtained from the <directive type="section" module="core"
1370 >LocationMatch</directive>.</p>
1372 <p>If you require a more flexible reverse-proxy configuration, see the
1373 <directive module="mod_rewrite">RewriteRule</directive> directive with the
1374 <code>[P]</code> flag.</p>
1376 <note type="warning">
1377 <title>Security Warning</title>
1378 <p>Take care when constructing the target URL of the rule, considering
1379 the security impact from allowing the client influence over the set of
1380 URLs to which your server will act as a proxy. Ensure that the scheme
1381 and hostname part of the URL is either fixed, or does not allow the
1382 client undue influence.</p>
1385 </directivesynopsis>
1388 <name>ProxyPassReverse</name>
1389 <description>Adjusts the URL in HTTP response headers sent from a reverse
1390 proxied server</description>
1391 <syntax>ProxyPassReverse [<var>path</var>] <var>url</var>
1392 [<var>interpolate</var>]</syntax>
1393 <contextlist><context>server config</context><context>virtual host</context>
1394 <context>directory</context>
1398 <p>This directive lets Apache httpd adjust the URL in the <code>Location</code>,
1399 <code>Content-Location</code> and <code>URI</code> headers on HTTP
1400 redirect responses. This is essential when Apache httpd is used as a
1401 reverse proxy (or gateway) to avoid by-passing the reverse proxy
1402 because of HTTP redirects on the backend servers which stay behind
1403 the reverse proxy.</p>
1405 <p>Only the HTTP response headers specifically mentioned above
1406 will be rewritten. Apache httpd will not rewrite other response
1407 headers, nor will it by default rewrite URL references inside HTML pages.
1408 This means that if the proxied content contains absolute URL
1409 references, they will by-pass the proxy. To rewrite HTML content to
1410 match the proxy, you must load and enable <module>mod_proxy_html</module>.
1413 <p><var>path</var> is the name of a local virtual path. <var>url</var> is a
1414 partial URL for the remote server - the same way they are used for the
1415 <directive module="mod_proxy">ProxyPass</directive> directive.</p>
1417 <p>For example, suppose the local server has address
1418 <code>http://example.com/</code>; then</p>
1420 <highlight language="config">
1421 ProxyPass /mirror/foo/ http://backend.example.com/
1422 ProxyPassReverse /mirror/foo/ http://backend.example.com/
1423 ProxyPassReverseCookieDomain backend.example.com public.example.com
1424 ProxyPassReverseCookiePath / /mirror/foo/
1427 <p>will not only cause a local request for the
1428 <code>http://example.com/mirror/foo/bar</code> to be internally converted
1429 into a proxy request to <code>http://backend.example.com/bar</code>
1430 (the functionality <code>ProxyPass</code> provides here). It also takes care
1431 of redirects the server <code>backend.example.com</code> sends: when
1432 <code>http://backend.example.com/bar</code> is redirected by him to
1433 <code>http://backend.example.com/quux</code> Apache httpd adjusts this to
1434 <code>http://example.com/mirror/foo/quux</code> before forwarding the HTTP
1435 redirect response to the client. Note that the hostname used for
1436 constructing the URL is chosen in respect to the setting of the <directive
1437 module="core">UseCanonicalName</directive> directive.</p>
1439 <p>Note that this <directive>ProxyPassReverse</directive> directive can
1440 also be used in conjunction with the proxy pass-through feature
1441 (<code>RewriteRule ... [P]</code>) from <module>mod_rewrite</module>
1442 because it doesn't depend on a corresponding <directive module="mod_proxy"
1443 >ProxyPass</directive> directive.</p>
1445 <p>The optional <var>interpolate</var> keyword, used together with
1446 <directive>ProxyPassInterpolateEnv</directive>, enables interpolation
1447 of environment variables specified using the format <var>${VARNAME}</var>.
1448 Note that interpolation is not supported within the scheme portion of a
1451 <p>When used inside a <directive type="section" module="core"
1452 >Location</directive> section, the first argument is omitted and the local
1453 directory is obtained from the <directive type="section" module="core"
1454 >Location</directive>. The same occurs inside a <directive type="section"
1455 module="core">LocationMatch</directive> section, but will probably not work as
1456 intended, as ProxyPassReverse will interpret the regexp literally as a
1457 path; if needed in this situation, specify the ProxyPassReverse outside
1458 the section, or in a separate <directive type="section" module="core"
1459 >Location</directive> section.</p>
1461 <p>This directive is not supported in <directive type="section" module="core"
1462 >Directory</directive> or <directive type="section" module="core"
1463 >Files</directive> sections.</p>
1465 </directivesynopsis>
1468 <name>ProxyPassReverseCookieDomain</name>
1469 <description>Adjusts the Domain string in Set-Cookie headers from a reverse-
1470 proxied server</description>
1471 <syntax>ProxyPassReverseCookieDomain <var>internal-domain</var>
1472 <var>public-domain</var> [<var>interpolate</var>]</syntax>
1473 <contextlist><context>server config</context><context>virtual host</context>
1474 <context>directory</context>
1477 <p>Usage is basically similar to
1478 <directive module="mod_proxy">ProxyPassReverse</directive>, but instead of
1479 rewriting headers that are a URL, this rewrites the <code>domain</code>
1480 string in <code>Set-Cookie</code> headers.</p>
1482 </directivesynopsis>
1486 <name>ProxyPassReverseCookiePath</name>
1487 <description>Adjusts the Path string in Set-Cookie headers from a reverse-
1488 proxied server</description>
1489 <syntax>ProxyPassReverseCookiePath <var>internal-path</var>
1490 <var>public-path</var> [<var>interpolate</var>]</syntax>
1491 <contextlist><context>server config</context><context>virtual host</context>
1492 <context>directory</context>
1496 Useful in conjunction with
1497 <directive module="mod_proxy">ProxyPassReverse</directive>
1498 in situations where backend URL paths are mapped to public paths on the
1499 reverse proxy. This directive rewrites the <code>path</code> string in
1500 <code>Set-Cookie</code> headers. If the beginning of the cookie path matches
1501 <var>internal-path</var>, the cookie path will be replaced with
1502 <var>public-path</var>.
1504 In the example given with
1505 <directive module="mod_proxy">ProxyPassReverse</directive>, the directive:
1507 <highlight language="config">
1508 ProxyPassReverseCookiePath / /mirror/foo/
1511 will rewrite a cookie with backend path <code>/</code> (or
1512 <code>/example</code> or, in fact, anything) to <code>/mirror/foo/</code>.
1515 </directivesynopsis>
1518 <name>ProxyBlock</name>
1519 <description>Disallow proxy requests to certain hosts</description>
1520 <syntax>ProxyBlock *|<var>hostname</var>|<var>partial-hostname</var> [<var>hostname</var>|<var>partial-hostname</var>]...</syntax>
1521 <contextlist><context>server config</context><context>virtual host</context>
1525 <p>The <directive>ProxyBlock</directive> directive can be used to
1526 block FTP or HTTP access to certain hosts via the proxy, based on
1527 a full or partial hostname match, or, if applicable, an IP address
1530 <p>Each of the arguments to the <directive>ProxyBlock</directive>
1531 directive can be either <code>*</code> or a alphanumeric string.
1532 At startup, the module will attempt to resolve every alphanumeric
1533 string from a DNS name to a set of IP addresses, but any DNS errors
1536 <p>If an asterisk "<code>*</code>" argument is specified,
1537 <module>mod_proxy</module> will deny access to all FTP or HTTP
1540 <p>Otherwise, for any request for an HTTP or FTP resource via the
1541 proxy, <module>mod_proxy</module> will check the hostname of the
1542 request URI against each specified string. If a partial string
1543 match is found, access is denied. If no matches against hostnames
1544 are found, and a remote (forward) proxy is configured using
1545 <directive>ProxyRemote</directive> or
1546 <directive>ProxyRemoteMatch</directive>, access is allowed. If no
1547 remote (forward) proxy is configured, the IP address of the
1548 hostname from the URI is compared against all resolved IP
1549 addresses determined at startup. Access is denied if any match is
1552 <p>Note that the DNS lookups may slow down the startup time of the
1555 <example><title>Example</title>
1556 <highlight language="config">
1557 ProxyBlock news.example.com auctions.example.com friends.example.com
1561 <p>Note that <code>example</code> would also be sufficient to match any
1564 <p>Hosts would also be matched if referenced by IP address.</p>
1566 <p>Note also that</p>
1568 <highlight language="config">
1572 <p>blocks connections to all sites.</p>
1574 </directivesynopsis>
1577 <name>ProxyReceiveBufferSize</name>
1578 <description>Network buffer size for proxied HTTP and FTP
1579 connections</description>
1580 <syntax>ProxyReceiveBufferSize <var>bytes</var></syntax>
1581 <default>ProxyReceiveBufferSize 0</default>
1582 <contextlist><context>server config</context><context>virtual host</context>
1586 <p>The <directive>ProxyReceiveBufferSize</directive> directive specifies an
1587 explicit (TCP/IP) network buffer size for proxied HTTP and FTP connections,
1588 for increased throughput. It has to be greater than <code>512</code> or set
1589 to <code>0</code> to indicate that the system's default buffer size should
1592 <example><title>Example</title>
1593 <highlight language="config">
1594 ProxyReceiveBufferSize 2048
1598 </directivesynopsis>
1601 <name>ProxyIOBufferSize</name>
1602 <description>Determine size of internal data throughput buffer</description>
1603 <syntax>ProxyIOBufferSize <var>bytes</var></syntax>
1604 <default>ProxyIOBufferSize 8192</default>
1605 <contextlist><context>server config</context><context>virtual host</context>
1609 <p>The <directive>ProxyIOBufferSize</directive> directive adjusts the size
1610 of the internal buffer, which is used as a scratchpad for the data between
1611 input and output. The size must be at least <code>512</code>.</p>
1613 <p>In almost every case there's no reason to change that value.</p>
1615 <p>If used with AJP this directive sets the maximum AJP packet size in
1616 bytes. Values larger than 65536 are set to 65536. If you change it from
1617 the default, you must also change the <code>packetSize</code> attribute of
1618 your AJP connector on the Tomcat side! The attribute
1619 <code>packetSize</code> is only available in Tomcat <code>5.5.20+</code>
1620 and <code>6.0.2+</code></p>
1622 <p>Normally it is not necessary to change the maximum packet size.
1623 Problems with the default value have been reported when sending
1624 certificates or certificate chains.</p>
1627 </directivesynopsis>
1630 <name>ProxyMaxForwards</name>
1631 <description>Maximium number of proxies that a request can be forwarded
1632 through</description>
1633 <syntax>ProxyMaxForwards <var>number</var></syntax>
1634 <default>ProxyMaxForwards -1</default>
1635 <contextlist><context>server config</context><context>virtual host</context>
1639 <p>The <directive>ProxyMaxForwards</directive> directive specifies the
1640 maximum number of proxies through which a request may pass, if there's no
1641 <code>Max-Forwards</code> header supplied with the request. This may
1642 be set to prevent infinite proxy loops, or a DoS attack.</p>
1644 <example><title>Example</title>
1645 <highlight language="config">
1650 <p>Note that setting <directive>ProxyMaxForwards</directive> is a
1651 violation of the HTTP/1.1 protocol (RFC2616), which forbids a Proxy
1652 setting <code>Max-Forwards</code> if the Client didn't set it.
1653 Earlier Apache httpd versions would always set it. A negative
1654 <directive>ProxyMaxForwards</directive> value, including the
1655 default -1, gives you protocol-compliant behaviour, but may
1656 leave you open to loops.</p>
1658 </directivesynopsis>
1661 <name>NoProxy</name>
1662 <description>Hosts, domains, or networks that will be connected to
1663 directly</description>
1664 <syntax>NoProxy <var>host</var> [<var>host</var>] ...</syntax>
1665 <contextlist><context>server config</context><context>virtual host</context>
1669 <p>This directive is only useful for Apache httpd proxy servers within
1670 intranets. The <directive>NoProxy</directive> directive specifies a
1671 list of subnets, IP addresses, hosts and/or domains, separated by
1672 spaces. A request to a host which matches one or more of these is
1673 always served directly, without forwarding to the configured
1674 <directive module="mod_proxy">ProxyRemote</directive> proxy server(s).</p>
1676 <example><title>Example</title>
1677 <highlight language="config">
1678 ProxyRemote * http://firewall.example.com:81
1679 NoProxy .example.com 192.168.112.0/21
1683 <p>The <var>host</var> arguments to the <directive>NoProxy</directive>
1684 directive are one of the following type list:</p>
1687 <!-- ===================== Domain ======================= -->
1688 <dt><var><a name="domain" id="domain">Domain</a></var></dt>
1690 <p>A <dfn>Domain</dfn> is a partially qualified DNS domain name, preceded
1691 by a period. It represents a list of hosts which logically belong to the
1692 same DNS domain or zone (<em>i.e.</em>, the suffixes of the hostnames are
1693 all ending in <var>Domain</var>).</p>
1695 <example><title>Examples</title>
1699 <p>To distinguish <var>Domain</var>s from <var><a href="#hostname"
1700 >Hostname</a></var>s (both syntactically and semantically; a DNS domain can
1701 have a DNS A record, too!), <var>Domain</var>s are always written with a
1704 <note><title>Note</title>
1705 <p>Domain name comparisons are done without regard to the case, and
1706 <var>Domain</var>s are always assumed to be anchored in the root of the
1707 DNS tree, therefore two domains <code>.ExAmple.com</code> and
1708 <code>.example.com.</code> (note the trailing period) are considered
1709 equal. Since a domain comparison does not involve a DNS lookup, it is much
1710 more efficient than subnet comparison.</p>
1713 <!-- ===================== SubNet ======================= -->
1714 <dt><var><a name="subnet" id="subnet">SubNet</a></var></dt>
1716 <p>A <dfn>SubNet</dfn> is a partially qualified internet address in
1717 numeric (dotted quad) form, optionally followed by a slash and the netmask,
1718 specified as the number of significant bits in the <var>SubNet</var>. It is
1719 used to represent a subnet of hosts which can be reached over a common
1720 network interface. In the absence of the explicit net mask it is assumed
1721 that omitted (or zero valued) trailing digits specify the mask. (In this
1722 case, the netmask can only be multiples of 8 bits wide.) Examples:</p>
1725 <dt><code>192.168</code> or <code>192.168.0.0</code></dt>
1726 <dd>the subnet 192.168.0.0 with an implied netmask of 16 valid bits
1727 (sometimes used in the netmask form <code>255.255.0.0</code>)</dd>
1728 <dt><code>192.168.112.0/21</code></dt>
1729 <dd>the subnet <code>192.168.112.0/21</code> with a netmask of 21
1730 valid bits (also used in the form <code>255.255.248.0</code>)</dd>
1733 <p>As a degenerate case, a <em>SubNet</em> with 32 valid bits is the
1734 equivalent to an <var><a href="#ipaddr">IPAddr</a></var>, while a <var>SubNet</var> with zero
1735 valid bits (<em>e.g.</em>, 0.0.0.0/0) is the same as the constant
1736 <var>_Default_</var>, matching any IP address.</p></dd>
1738 <!-- ===================== IPAddr ======================= -->
1739 <dt><var><a name="ipaddr" id="ipaddr">IPAddr</a></var></dt>
1741 <p>A <dfn>IPAddr</dfn> represents a fully qualified internet address in
1742 numeric (dotted quad) form. Usually, this address represents a host, but
1743 there need not necessarily be a DNS domain name connected with the
1745 <example><title>Example</title>
1749 <note><title>Note</title>
1750 <p>An <var>IPAddr</var> does not need to be resolved by the DNS system, so
1751 it can result in more effective apache performance.</p>
1754 <!-- ===================== Hostname ======================= -->
1755 <dt><var><a name="hostname" id="hostname">Hostname</a></var></dt>
1757 <p>A <dfn>Hostname</dfn> is a fully qualified DNS domain name which can
1758 be resolved to one or more <var><a href="#ipaddr">IPAddrs</a></var> via the
1759 DNS domain name service. It represents a logical host (in contrast to
1760 <var><a href="#domain">Domain</a></var>s, see above) and must be resolvable
1761 to at least one <var><a href="#ipaddr">IPAddr</a></var> (or often to a list
1762 of hosts with different <var><a href="#ipaddr">IPAddr</a></var>s).</p>
1764 <example><title>Examples</title>
1765 prep.ai.example.edu<br />
1769 <note><title>Note</title>
1770 <p>In many situations, it is more effective to specify an <var><a
1771 href="#ipaddr">IPAddr</a></var> in place of a <var>Hostname</var> since a
1772 DNS lookup can be avoided. Name resolution in Apache httpd can take a remarkable
1773 deal of time when the connection to the name server uses a slow PPP
1775 <p><var>Hostname</var> comparisons are done without regard to the case,
1776 and <var>Hostname</var>s are always assumed to be anchored in the root
1777 of the DNS tree, therefore two hosts <code>WWW.ExAmple.com</code>
1778 and <code>www.example.com.</code> (note the trailing period) are
1779 considered equal.</p>
1783 <seealso><a href="../dns-caveats.html">DNS Issues</a></seealso>
1784 </directivesynopsis>
1787 <name>ProxyTimeout</name>
1788 <description>Network timeout for proxied requests</description>
1789 <syntax>ProxyTimeout <var>seconds</var></syntax>
1790 <default>Value of <directive module="core">Timeout</directive></default>
1791 <contextlist><context>server config</context><context>virtual host</context>
1795 <p>This directive allows a user to specifiy a timeout on proxy requests.
1796 This is useful when you have a slow/buggy appserver which hangs, and you
1797 would rather just return a timeout and fail gracefully instead of waiting
1798 however long it takes the server to return.</p>
1800 </directivesynopsis>
1803 <name>ProxyDomain</name>
1804 <description>Default domain name for proxied requests</description>
1805 <syntax>ProxyDomain <var>Domain</var></syntax>
1806 <contextlist><context>server config</context><context>virtual host</context>
1810 <p>This directive is only useful for Apache httpd proxy servers within
1811 intranets. The <directive>ProxyDomain</directive> directive specifies
1812 the default domain which the apache proxy server will belong to. If a
1813 request to a host without a domain name is encountered, a redirection
1814 response to the same host with the configured <var>Domain</var> appended
1815 will be generated.</p>
1817 <example><title>Example</title>
1818 <highlight language="config">
1819 ProxyRemote * http://firewall.example.com:81<br />
1820 NoProxy .example.com 192.168.112.0/21<br />
1821 ProxyDomain .example.com
1825 </directivesynopsis>
1828 <name>ProxyVia</name>
1829 <description>Information provided in the <code>Via</code> HTTP response
1830 header for proxied requests</description>
1831 <syntax>ProxyVia On|Off|Full|Block</syntax>
1832 <default>ProxyVia Off</default>
1833 <contextlist><context>server config</context><context>virtual host</context>
1837 <p>This directive controls the use of the <code>Via:</code> HTTP
1838 header by the proxy. Its intended use is to control the flow of
1839 proxy requests along a chain of proxy servers. See <a
1840 href="http://www.ietf.org/rfc/rfc2616.txt">RFC 2616</a> (HTTP/1.1), section
1841 14.45 for an explanation of <code>Via:</code> header lines.</p>
1844 <li>If set to <code>Off</code>, which is the default, no special processing
1845 is performed. If a request or reply contains a <code>Via:</code> header,
1846 it is passed through unchanged.</li>
1848 <li>If set to <code>On</code>, each request and reply will get a
1849 <code>Via:</code> header line added for the current host.</li>
1851 <li>If set to <code>Full</code>, each generated <code>Via:</code> header
1852 line will additionally have the Apache httpd server version shown as a
1853 <code>Via:</code> comment field.</li>
1855 <li>If set to <code>Block</code>, every proxy request will have all its
1856 <code>Via:</code> header lines removed. No new <code>Via:</code> header will
1860 </directivesynopsis>
1863 <name>ProxyErrorOverride</name>
1864 <description>Override error pages for proxied content</description>
1865 <syntax>ProxyErrorOverride On|Off</syntax>
1866 <default>ProxyErrorOverride Off</default>
1867 <contextlist><context>server config</context><context>virtual host</context>
1868 <context>directory</context>
1872 <p>This directive is useful for reverse-proxy setups, where you want to
1873 have a common look and feel on the error pages seen by the end user.
1874 This also allows for included files (via
1875 <module>mod_include</module>'s SSI) to get
1876 the error code and act accordingly (default behavior would display
1877 the error page of the proxied server, turning this on shows the SSI
1880 <p>This directive does not affect the processing of informational (1xx),
1881 normal success (2xx), or redirect (3xx) responses.</p>
1883 </directivesynopsis>
1886 <name>ProxyPassInterpolateEnv</name>
1887 <description>Enable Environment Variable interpolation in Reverse Proxy configurations</description>
1888 <syntax>ProxyPassInterpolateEnv On|Off</syntax>
1889 <default>ProxyPassInterpolateEnv Off</default>
1890 <contextlist><context>server config</context>
1891 <context>virtual host</context>
1892 <context>directory</context>
1896 <p>This directive, together with the <var>interpolate</var> argument to
1897 <directive>ProxyPass</directive>, <directive>ProxyPassReverse</directive>,
1898 <directive>ProxyPassReverseCookieDomain</directive> and
1899 <directive>ProxyPassReverseCookiePath</directive>
1900 enables reverse proxies to be dynamically
1901 configured using environment variables, which may be set by
1902 another module such as <module>mod_rewrite</module>.
1903 It affects the <directive>ProxyPass</directive>,
1904 <directive>ProxyPassReverse</directive>,
1905 <directive>ProxyPassReverseCookieDomain</directive>, and
1906 <directive>ProxyPassReverseCookiePath</directive> directives,
1907 and causes them to substitute the value of an environment
1908 variable <code>varname</code> for the string <code>${varname}</code>
1909 in configuration directives (if the <var>interpolate</var> option is set).</p>
1910 <p>Keep this turned off (for server performance) unless you need it!</p>
1912 </directivesynopsis>
1915 <name>ProxyStatus</name>
1916 <description>Show Proxy LoadBalancer status in mod_status</description>
1917 <syntax>ProxyStatus Off|On|Full</syntax>
1918 <default>ProxyStatus Off</default>
1919 <contextlist><context>server config</context>
1920 <context>virtual host</context>
1924 <p>This directive determines whether or not proxy
1925 loadbalancer status data is displayed via the <module>mod_status</module>
1926 server-status page.</p>
1927 <note><title>Note</title>
1928 <p><strong>Full</strong> is synonymous with <strong>On</strong></p>
1932 </directivesynopsis>
1935 <name>ProxyAddHeaders</name>
1936 <description>Add proxy information in X-Forwarded-* headers</description>
1937 <syntax>ProxyAddHeaders Off|On</syntax>
1938 <default>ProxyAddHeaders On</default>
1939 <contextlist><context>server config</context>
1940 <context>virtual host</context>
1941 <context>directory</context>
1943 <compatibility>Available in version 2.3.10 and later</compatibility>
1946 <p>This directive determines whether or not proxy related information should be passed to the
1947 backend server through X-Forwarded-For, X-Forwarded-Host and X-Forwarded-Server HTTP headers.</p>
1948 <note><title>Effectiveness</title>
1949 <p>This option is of use only for HTTP proxying, as handled by <module>mod_proxy_http</module>.</p>
1952 </directivesynopsis>
1955 <name>ProxySourceAddress</name>
1956 <description>Set local IP address for outgoing proxy connections</description>
1957 <syntax>ProxySourceAddress <var>address</var></syntax>
1958 <contextlist><context>server config</context>
1959 <context>virtual host</context>
1961 <compatibility>Available in version 2.3.9 and later</compatibility>
1964 <p>This directive allows to set a specific local address to bind to when connecting
1965 to a backend server.</p>
1967 </directivesynopsis>