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diff --git a/docs/manual/mod/mod_proxy.html.en b/docs/manual/mod/mod_proxy.html.en new file mode 100644 index 0000000..88e3562 --- /dev/null +++ b/docs/manual/mod/mod_proxy.html.en @@ -0,0 +1,2173 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head> +<meta content="text/html; charset=UTF-8" http-equiv="Content-Type" /> +<!-- + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + This file is generated from xml source: DO NOT EDIT + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + --> +<title>mod_proxy - Apache HTTP Server Version 2.4</title> +<link href="../style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" /> +<link href="../style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" /> +<link href="../style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" /><link rel="stylesheet" type="text/css" href="../style/css/prettify.css" /> +<script src="../style/scripts/prettify.min.js" type="text/javascript"> +</script> + +<link href="../images/favicon.ico" rel="shortcut icon" /></head> +<body> +<div id="page-header"> +<p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p> +<p class="apache">Apache HTTP Server Version 2.4</p> +<img alt="" src="../images/feather.png" /></div> +<div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div> +<div id="path"> +<a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.4</a> > <a href="./">Modules</a></div> +<div id="page-content"> +<div id="preamble"><h1>Apache Module mod_proxy</h1> +<div class="toplang"> +<p><span>Available Languages: </span><a href="../en/mod/mod_proxy.html" title="English"> en </a> | +<a href="../fr/mod/mod_proxy.html" hreflang="fr" rel="alternate" title="Français"> fr </a> | +<a href="../ja/mod/mod_proxy.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a></p> +</div> +<table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Multi-protocol proxy/gateway server</td></tr> +<tr><th><a href="module-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="module-dict.html#ModuleIdentifier">Module Identifier:</a></th><td>proxy_module</td></tr> +<tr><th><a href="module-dict.html#SourceFile">Source File:</a></th><td>mod_proxy.c</td></tr></table> +<h3>Summary</h3> + + <div class="warning"><h3>Warning</h3> + <p>Do not enable proxying with <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> until you have <a href="#access">secured your server</a>. Open proxy servers are dangerous both to your + network and to the Internet at large.</p> + </div> + + <p><code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> and related modules implement a + proxy/gateway for Apache HTTP Server, supporting a number of popular + protocols as well as several different load balancing algorithms. + Third-party modules can add support for additional protocols and + load balancing algorithms.</p> + + <p>A set of modules must be loaded into the server to provide the + necessary features. These modules can be included statically at + build time or dynamically via the + <code class="directive"><a href="../mod/mod_so.html#loadmodule">LoadModule</a></code> directive). + The set must include:</p> + + <ul> + <li><code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>, which provides basic proxy + capabilities</li> + + <li><code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code> and one or more + balancer modules if load balancing is required. (See + <code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code> for more information.)</li> + + <li>one or more proxy scheme, or protocol, modules: + + <table class="bordered"> + <tr><th>Protocol</th><th>Module</th></tr> + <tr><td>AJP13 (Apache JServe Protocol version + 1.3)</td><td><code class="module"><a href="../mod/mod_proxy_ajp.html">mod_proxy_ajp</a></code></td></tr> + <tr><td>CONNECT (for + SSL)</td><td><code class="module"><a href="../mod/mod_proxy_connect.html">mod_proxy_connect</a></code></td></tr> + <tr><td>FastCGI</td><td><code class="module"><a href="../mod/mod_proxy_fcgi.html">mod_proxy_fcgi</a></code></td></tr> + <tr><td>ftp</td><td><code class="module"><a href="../mod/mod_proxy_ftp.html">mod_proxy_ftp</a></code></td></tr> + <tr><td>HTTP/0.9, HTTP/1.0, and + HTTP/1.1</td><td><code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code></td></tr> + <tr><td>HTTP/2.0</td><td><code class="module"><a href="../mod/mod_proxy_http2.html">mod_proxy_http2</a></code></td></tr> + <tr><td>SCGI</td><td><code class="module"><a href="../mod/mod_proxy_scgi.html">mod_proxy_scgi</a></code></td></tr> + <tr><td>UWSGI</td><td><code class="module"><a href="../mod/mod_proxy_uwsgi.html">mod_proxy_uwsgi</a></code></td></tr> + <tr><td>WS and WSS (Web-sockets)</td><td><code class="module"><a href="../mod/mod_proxy_wstunnel.html">mod_proxy_wstunnel</a></code></td></tr> + </table> + </li> + </ul> + + <p>In addition, extended features are provided by other modules. + Caching is provided by <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code> and related + modules. The ability to contact remote servers using the SSL/TLS + protocol is provided by the <code>SSLProxy*</code> directives of + <code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code>. These additional modules will need + to be loaded and configured to take advantage of these features.</p> +</div> +<div id="quickview"><a href="https://www.apache.org/foundation/contributing.html" class="badge"><img src="https://www.apache.org/images/SupportApache-small.png" alt="Support Apache!" /></a><h3>Topics</h3> +<ul id="topics"> +<li><img alt="" src="../images/down.gif" /> <a href="#forwardreverse">Forward Proxies and Reverse + Proxies/Gateways</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#examples">Basic Examples</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#handler">Access via Handler</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#workers">Workers</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#access">Controlling Access to Your Proxy</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#startup">Slow Startup</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#intranet">Intranet Proxy</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#envsettings">Protocol Adjustments</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#request-bodies">Request Bodies</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#x-headers">Reverse Proxy Request Headers</a></li> +</ul><h3 class="directives">Directives</h3> +<ul id="toc"> +<li><img alt="" src="../images/down.gif" /> <a href="#balancergrowth">BalancerGrowth</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#balancerinherit">BalancerInherit</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#balancermember">BalancerMember</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#balancerpersist">BalancerPersist</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#noproxy">NoProxy</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxy"><Proxy></a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxy100continue">Proxy100Continue</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxyaddheaders">ProxyAddHeaders</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxybadheader">ProxyBadHeader</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxyblock">ProxyBlock</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxydomain">ProxyDomain</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxyerroroverride">ProxyErrorOverride</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxyiobuffersize">ProxyIOBufferSize</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxymatch"><ProxyMatch></a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxymaxforwards">ProxyMaxForwards</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxypass">ProxyPass</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxypassinherit">ProxyPassInherit</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxypassinterpolateenv">ProxyPassInterpolateEnv</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxypassmatch">ProxyPassMatch</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxypassreverse">ProxyPassReverse</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxypassreversecookiedomain">ProxyPassReverseCookieDomain</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxypassreversecookiepath">ProxyPassReverseCookiePath</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxypreservehost">ProxyPreserveHost</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxyreceivebuffersize">ProxyReceiveBufferSize</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxyremote">ProxyRemote</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxyremotematch">ProxyRemoteMatch</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxyrequests">ProxyRequests</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxyset">ProxySet</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxysourceaddress">ProxySourceAddress</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxystatus">ProxyStatus</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxytimeout">ProxyTimeout</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#proxyvia">ProxyVia</a></li> +</ul> +<h3>Bugfix checklist</h3><ul class="seealso"><li><a href="https://www.apache.org/dist/httpd/CHANGES_2.4">httpd changelog</a></li><li><a href="https://bz.apache.org/bugzilla/buglist.cgi?bug_status=__open__&list_id=144532&product=Apache%20httpd-2&query_format=specific&order=changeddate%20DESC%2Cpriority%2Cbug_severity&component=mod_proxy">Known issues</a></li><li><a href="https://bz.apache.org/bugzilla/enter_bug.cgi?product=Apache%20httpd-2&component=mod_proxy">Report a bug</a></li></ul><h3>See also</h3> +<ul class="seealso"> +<li><code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code></li> +<li><code class="module"><a href="../mod/mod_proxy_ajp.html">mod_proxy_ajp</a></code></li> +<li><code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code></li> +<li><code class="module"><a href="../mod/mod_proxy_connect.html">mod_proxy_connect</a></code></li> +<li><code class="module"><a href="../mod/mod_proxy_fcgi.html">mod_proxy_fcgi</a></code></li> +<li><code class="module"><a href="../mod/mod_proxy_ftp.html">mod_proxy_ftp</a></code></li> +<li><code class="module"><a href="../mod/mod_proxy_hcheck.html">mod_proxy_hcheck</a></code></li> +<li><code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code></li> +<li><code class="module"><a href="../mod/mod_proxy_scgi.html">mod_proxy_scgi</a></code></li> +<li><code class="module"><a href="../mod/mod_proxy_wstunnel.html">mod_proxy_wstunnel</a></code></li> +<li><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></li> +<li><a href="#comments_section">Comments</a></li></ul></div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="forwardreverse" id="forwardreverse">Forward Proxies and Reverse + Proxies/Gateways</a></h2> + <p>Apache HTTP Server can be configured in both a <dfn>forward</dfn> and + <dfn>reverse</dfn> proxy (also known as <dfn>gateway</dfn>) mode.</p> + + <p>An ordinary <dfn>forward proxy</dfn> is an intermediate + server that sits between the client and the <em>origin + server</em>. In order to get content from the origin server, + the client sends a request to the proxy naming the origin server + as the target. The proxy then requests the content from the + origin server and returns it to the client. The client must be + specially configured to use the forward proxy to access other + sites.</p> + + <p>A typical usage of a forward proxy is to provide Internet + access to internal clients that are otherwise restricted by a + firewall. The forward proxy can also use caching (as provided + by <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code>) to reduce network usage.</p> + + <p>The forward proxy is activated using the <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> directive. Because + forward proxies allow clients to access arbitrary sites through + your server and to hide their true origin, it is essential that + you <a href="#access">secure your server</a> so that only + authorized clients can access the proxy before activating a + forward proxy.</p> + + <p>A <dfn>reverse proxy</dfn> (or <dfn>gateway</dfn>), by + contrast, appears to the client just like an ordinary web + server. No special configuration on the client is necessary. + The client makes ordinary requests for content in the namespace + of the reverse proxy. The reverse proxy then decides where to + send those requests and returns the content as if it were itself + the origin.</p> + + <p>A typical usage of a reverse proxy is to provide Internet + users access to a server that is behind a firewall. Reverse + proxies can also be used to balance load among several back-end + servers or to provide caching for a slower back-end server. + In addition, reverse proxies can be used simply to bring + several servers into the same URL space.</p> + + <p>A reverse proxy is activated using the <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive or the + <code>[P]</code> flag to the <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> directive. It is + <strong>not</strong> necessary to turn <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> on in order to + configure a reverse proxy.</p> + </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="examples" id="examples">Basic Examples</a></h2> + + <p>The examples below are only a very basic idea to help you + get started. Please read the documentation on the individual + directives.</p> + + <p>In addition, if you wish to have caching enabled, consult + the documentation from <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code>.</p> + + <div class="example"><h3>Reverse Proxy</h3><pre class="prettyprint lang-config">ProxyPass "/foo" "http://foo.example.com/bar" +ProxyPassReverse "/foo" "http://foo.example.com/bar"</pre> +</div> + + <div class="example"><h3>Forward Proxy</h3><pre class="prettyprint lang-config">ProxyRequests On +ProxyVia On + +<Proxy "*"> + Require host internal.example.com +</Proxy></pre> +</div> + <div class="example"><h3><a id="wsupgrade" name="wsupgrade">Websocket Upgrade (2.4.47 and later)</a></h3><pre class="prettyprint lang-config">ProxyPass "/some/ws/capable/path/" "http://example.com/some/ws/capable/path/" upgrade=websocket</pre> +</div> + </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="handler" id="handler">Access via Handler</a></h2> + + <p>You can also force a request to be handled as a reverse-proxy + request, by creating a suitable Handler pass-through. The example + configuration below will pass all requests for PHP scripts to the + specified FastCGI server using reverse proxy: + </p> + + <div class="example"><h3>Reverse Proxy PHP scripts</h3><pre class="prettyprint lang-config"><FilesMatch "\.php$"> + # Unix sockets require 2.4.7 or later + SetHandler "proxy:unix:/path/to/app.sock|fcgi://localhost/" +</FilesMatch></pre> +</div> + + <p>This feature is available in Apache HTTP Server 2.4.10 and later.</p> + + </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="workers" id="workers">Workers</a></h2> + <p>The proxy manages the configuration of origin servers and their + communication parameters in objects called <dfn>workers</dfn>. + There are two built-in workers: the default forward proxy worker and the + default reverse proxy worker. Additional workers can be configured + explicitly.</p> + + <p>The two default workers have a fixed configuration + and will be used if no other worker matches the request. + They do not use HTTP Keep-Alive or connection reuse. + The TCP connections to the origin server will instead be + opened and closed for each request.</p> + + <p>Explicitly configured workers are identified by their URL. + They are usually created and configured using + <code class="directive"><a href="#proxypass">ProxyPass</a></code> or + <code class="directive"><a href="#proxypassmatch">ProxyPassMatch</a></code> when used + for a reverse proxy:</p> + + <pre class="prettyprint lang-config">ProxyPass "/example" "http://backend.example.com" connectiontimeout=5 timeout=30</pre> + + + <p>This will create a worker associated with the origin server URL + <code>http://backend.example.com</code> that will use the given timeout + values. When used in a forward proxy, workers are usually defined + via the <code class="directive"><a href="#proxyset">ProxySet</a></code> directive:</p> + + <pre class="prettyprint lang-config">ProxySet "http://backend.example.com" connectiontimeout=5 timeout=30</pre> + + + <p>or alternatively using <code class="directive"><a href="#proxy">Proxy</a></code> + and <code class="directive"><a href="#proxyset">ProxySet</a></code>:</p> + + <pre class="prettyprint lang-config"><Proxy "http://backend.example.com"> + ProxySet connectiontimeout=5 timeout=30 +</Proxy></pre> + + + <p>Using explicitly configured workers in the forward mode is + not very common, because forward proxies usually communicate with many + different origin servers. Creating explicit workers for some of the + origin servers can still be useful if they are used very often. + Explicitly configured workers have no concept of forward or reverse + proxying by themselves. They encapsulate a common concept of + communication with origin servers. A worker created by + <code class="directive"><a href="#proxypass">ProxyPass</a></code> for use in a + reverse proxy will also be used for forward proxy requests whenever + the URL to the origin server matches the worker URL, and vice versa.</p> + + <p>The URL identifying a direct worker is the URL of its + origin server including any path components given:</p> + + <pre class="prettyprint lang-config">ProxyPass "/examples" "http://backend.example.com/examples" +ProxyPass "/docs" "http://backend.example.com/docs"</pre> + + + <p>This example defines two different workers, each using a separate + connection pool and configuration.</p> + + <div class="warning"><h3>Worker Sharing</h3> + <p>Worker sharing happens if the worker URLs overlap, which occurs when + the URL of some worker is a leading substring of the URL of another + worker defined later in the configuration file. In the following example</p> + + <pre class="prettyprint lang-config">ProxyPass "/apps" "http://backend.example.com/" timeout=60 +ProxyPass "/examples" "http://backend.example.com/examples" timeout=10</pre> + + + <p>the second worker isn't actually created. Instead the first + worker is used. The benefit is, that there is only one connection pool, + so connections are more often reused. Note that all configuration attributes + given explicitly for the later worker will be ignored. This will be logged + as a warning. In the above example, the resulting timeout value + for the URL <code>/examples</code> will be <code>60</code> instead + of <code>10</code>!</p> + + <p>If you want to avoid worker sharing, sort your worker definitions + by URL length, starting with the longest worker URLs. If you want to maximize + worker sharing, use the reverse sort order. See also the related warning about + ordering <code class="directive"><a href="#proxypass">ProxyPass</a></code> directives.</p> + + </div> + + <p>Explicitly configured workers come in two flavors: + <dfn>direct workers</dfn> and <dfn>(load) balancer workers</dfn>. + They support many important configuration attributes which are + described below in the <code class="directive"><a href="#proxypass">ProxyPass</a></code> + directive. The same attributes can also be set using + <code class="directive"><a href="#proxyset">ProxySet</a></code>.</p> + + <p>The set of options available for a direct worker + depends on the protocol which is specified in the origin server URL. + Available protocols include <code>ajp</code>, <code>fcgi</code>, + <code>ftp</code>, <code>http</code> and <code>scgi</code>.</p> + + <p>Balancer workers are virtual workers that use direct workers known + as their members to actually handle the requests. Each balancer can + have multiple members. When it handles a request, it chooses a member + based on the configured load balancing algorithm.</p> + + <p>A balancer worker is created if its worker URL uses + <code>balancer</code> as the protocol scheme. + The balancer URL uniquely identifies the balancer worker. + Members are added to a balancer using + <code class="directive"><a href="#balancermember">BalancerMember</a></code>.</p> + + <div class="note"><h3>DNS resolution for origin domains</h3> + <p>DNS resolution happens when the socket to + the origin domain is created for the first time. + When connection reuse is enabled, each backend domain is resolved + only once per child process, and cached for all further connections + until the child is recycled. This information should to be considered + while planning DNS maintenance tasks involving backend domains. + Please also check <code class="directive"><a href="#proxypass">ProxyPass</a></code> + parameters for more details about connection reuse. + </p> + </div> + + </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="access" id="access">Controlling Access to Your Proxy</a></h2> + <p>You can control who can access your proxy via the <code class="directive"><a href="#proxy"><Proxy></a></code> control block as in + the following example:</p> + + <pre class="prettyprint lang-config"><Proxy "*"> + Require ip 192.168.0 +</Proxy></pre> + + + <p>For more information on access control directives, see + <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code>.</p> + + <p>Strictly limiting access is essential if you are using a + forward proxy (using the <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> directive). + Otherwise, your server can be used by any client to access + arbitrary hosts while hiding his or her true identity. This is + dangerous both for your network and for the Internet at large. + When using a reverse proxy (using the <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive with + <code>ProxyRequests Off</code>), access control is less + critical because clients can only contact the hosts that you + have specifically configured.</p> + + <p><strong>See Also</strong> the <a href="mod_proxy_http.html#env">Proxy-Chain-Auth</a> environment variable.</p> + + </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="startup" id="startup">Slow Startup</a></h2> + <p>If you're using the <code class="directive"><a href="#proxyblock">ProxyBlock</a></code> directive, hostnames' IP addresses are looked up + and cached during startup for later match test. This may take a few + seconds (or more) depending on the speed with which the hostname lookups + occur.</p> + </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="intranet" id="intranet">Intranet Proxy</a></h2> + <p>An Apache httpd proxy server situated in an intranet needs to forward + external requests through the company's firewall (for this, configure + the <code class="directive"><a href="#proxyremote">ProxyRemote</a></code> directive + to forward the respective <var>scheme</var> to the firewall proxy). + However, when it has to + access resources within the intranet, it can bypass the firewall when + accessing hosts. The <code class="directive"><a href="#noproxy">NoProxy</a></code> + directive is useful for specifying which hosts belong to the intranet and + should be accessed directly.</p> + + <p>Users within an intranet tend to omit the local domain name from their + WWW requests, thus requesting "http://somehost/" instead of + <code>http://somehost.example.com/</code>. Some commercial proxy servers + let them get away with this and simply serve the request, implying a + configured local domain. When the <code class="directive"><a href="#proxydomain">ProxyDomain</a></code> directive is used and the server is <a href="#proxyrequests">configured for proxy service</a>, Apache httpd can return + a redirect response and send the client to the correct, fully qualified, + server address. This is the preferred method since the user's bookmark + files will then contain fully qualified hosts.</p> + </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="envsettings" id="envsettings">Protocol Adjustments</a></h2> + <p>For circumstances where <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> is sending + requests to an origin server that doesn't properly implement + keepalives or HTTP/1.1, there are two <a href="../env.html">environment variables</a> that can force the + request to use HTTP/1.0 with no keepalive. These are set via the + <code class="directive"><a href="../mod/mod_env.html#setenv">SetEnv</a></code> directive.</p> + + <p>These are the <code>force-proxy-request-1.0</code> and + <code>proxy-nokeepalive</code> notes.</p> + + <pre class="prettyprint lang-config"><Location "/buggyappserver/"> + ProxyPass "http://buggyappserver:7001/foo/" + SetEnv force-proxy-request-1.0 1 + SetEnv proxy-nokeepalive 1 +</Location></pre> + + + <p> In 2.4.26 and later, the "no-proxy" environment variable can be set to disable + <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> processing the current request. + This variable should be set with <code class="directive"><a href="../mod/mod_setenvif.html#setenvif">SetEnvIf</a></code>, as <code class="directive"><a href="../mod/mod_env.html#setenv">SetEnv</a></code> + is not evaluated early enough.</p> + + </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="request-bodies" id="request-bodies">Request Bodies</a></h2> + + <p>Some request methods such as POST include a request body. + The HTTP protocol requires that requests which include a body + either use chunked transfer encoding or send a + <code>Content-Length</code> request header. When passing these + requests on to the origin server, <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code> + will always attempt to send the <code>Content-Length</code>. But + if the body is large and the original request used chunked + encoding, then chunked encoding may also be used in the upstream + request. You can control this selection using <a href="../env.html">environment variables</a>. Setting + <code>proxy-sendcl</code> ensures maximum compatibility with + upstream servers by always sending the + <code>Content-Length</code>, while setting + <code>proxy-sendchunked</code> minimizes resource usage by using + chunked encoding.</p> + + <p>Under some circumstances, the server must spool request bodies + to disk to satisfy the requested handling of request bodies. For + example, this spooling will occur if the original body was sent with + chunked encoding (and is large), but the administrator has + asked for backend requests to be sent with Content-Length or as HTTP/1.0. + This spooling can also occur if the request body already has a + Content-Length header, but the server is configured to filter incoming + request bodies.</p> + + </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="x-headers" id="x-headers">Reverse Proxy Request Headers</a></h2> + + <p>When acting in a reverse-proxy mode (using the <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive, for example), + <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code> adds several request headers in + order to pass information to the origin server. These headers + are:</p> + + <dl> + <dt><code>X-Forwarded-For</code></dt> + <dd>The IP address of the client.</dd> + <dt><code>X-Forwarded-Host</code></dt> + <dd>The original host requested by the client in the <code>Host</code> + HTTP request header.</dd> + <dt><code>X-Forwarded-Server</code></dt> + <dd>The hostname of the proxy server.</dd> + </dl> + + <p>Be careful when using these headers on the origin server, since + they will contain more than one (comma-separated) value if the + original request already contained one of these headers. For + example, you can use <code>%{X-Forwarded-For}i</code> in the log + format string of the origin server to log the original clients IP + address, but you may get more than one address if the request + passes through several proxies.</p> + + <p>See also the <code class="directive"><a href="#proxypreservehost">ProxyPreserveHost</a></code> and <code class="directive"><a href="#proxyvia">ProxyVia</a></code> directives, which control + other request headers.</p> + + <p>Note: If you need to specify custom request headers to be + added to the forwarded request, use the + <code class="directive"><a href="../mod/mod_headers.html#requestheader">RequestHeader</a></code> + directive.</p> + + </div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="BalancerGrowth" id="BalancerGrowth">BalancerGrowth</a> <a name="balancergrowth" id="balancergrowth">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of additional Balancers that can be added Post-configuration</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>BalancerGrowth <var>#</var></code></td></tr> +<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>BalancerGrowth 5</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>BalancerGrowth is only available in Apache HTTP Server 2.3.13 + and later.</td></tr> +</table> + <p>This directive allows for growth potential in the number of + Balancers available for a virtualhost in addition to the + number pre-configured. It only takes effect if there is at + least one pre-configured Balancer.</p> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="BalancerInherit" id="BalancerInherit">BalancerInherit</a> <a name="balancerinherit" id="balancerinherit">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Inherit ProxyPassed Balancers/Workers from the main server</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>BalancerInherit On|Off</code></td></tr> +<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>BalancerInherit On</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>BalancerInherit is only available in Apache HTTP Server 2.4.5 and later.</td></tr> +</table> + <p>This directive will cause the current server/vhost to "inherit" ProxyPass + Balancers and Workers defined in the main server. This can cause issues and + inconsistent behavior if using the Balancer Manager and so should be disabled + if using that feature.</p> + <p>The setting in the global server defines the default for all vhosts.</p> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="BalancerMember" id="BalancerMember">BalancerMember</a> <a name="balancermember" id="balancermember">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Add a member to a load balancing group</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>BalancerMember [<var>balancerurl</var>] <var>url</var> [<var>key=value [key=value ...]]</var></code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>BalancerMember is only available in Apache HTTP Server 2.2 + and later.</td></tr> +</table> + <p>This directive adds a member to a load balancing group. It can be used + within a <code><Proxy <var>balancer://</var>...></code> container + directive and can take any of the key value pair parameters available to + <code class="directive"><a href="#proxypass">ProxyPass</a></code> directives.</p> + <p>One additional parameter is available only to <code class="directive">BalancerMember</code> directives: + <var>loadfactor</var>. This is the member load factor - a decimal number between 1.0 + (default) and 100.0, which defines the weighted load to be applied to the + member in question.</p> + <p>The <var>balancerurl</var> is only needed when not within a + <code><Proxy <var>balancer://</var>...></code> + container directive. It corresponds to the url of a balancer defined in + <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.</p> + <p>The path component of the balancer URL in any + <code><Proxy <var>balancer://</var>...></code> container directive + is ignored.</p> + <p>Trailing slashes should typically be removed from the URL of a + <code class="directive">BalancerMember</code>.</p> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="BalancerPersist" id="BalancerPersist">BalancerPersist</a> <a name="balancerpersist" id="balancerpersist">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Attempt to persist changes made by the Balancer Manager across restarts.</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>BalancerPersist On|Off</code></td></tr> +<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>BalancerPersist Off</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>BalancerPersist is only available in Apache HTTP Server 2.4.4 and later.</td></tr> +</table> + <p>This directive will cause the shared memory storage associated + with the balancers and balancer members to be persisted across + restarts. This allows these local changes to not be lost during the + normal restart/graceful state transitions.</p> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="NoProxy" id="NoProxy">NoProxy</a> <a name="noproxy" id="noproxy">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Hosts, domains, or networks that will be connected to +directly</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>NoProxy <var>host</var> [<var>host</var>] ...</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +</table> + <p>This directive is only useful for Apache httpd proxy servers within + intranets. The <code class="directive">NoProxy</code> directive specifies a + list of subnets, IP addresses, hosts and/or domains, separated by + spaces. A request to a host which matches one or more of these is + always served directly, without forwarding to the configured + <code class="directive"><a href="#proxyremote">ProxyRemote</a></code> proxy server(s).</p> + + <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">ProxyRemote "*" "http://firewall.example.com:81" +NoProxy ".example.com" "192.168.112.0/21"</pre> +</div> + + <p>The <var>host</var> arguments to the <code class="directive">NoProxy</code> + directive are one of the following type list:</p> + + <dl> + + <dt><var><a name="domain" id="domain">Domain</a></var></dt> + <dd> + <p>A <dfn>Domain</dfn> is a partially qualified DNS domain name, preceded + by a period. It represents a list of hosts which logically belong to the + same DNS domain or zone (<em>i.e.</em>, the suffixes of the hostnames are + all ending in <var>Domain</var>).</p> + + <div class="example"><h3>Examples</h3><p><code> + .com .example.org. + </code></p></div> + + <p>To distinguish <var>Domain</var>s from <var><a href="#hostname">Hostname</a></var>s (both syntactically and semantically; a DNS domain can + have a DNS A record, too!), <var>Domain</var>s are always written with a + leading period.</p> + + <div class="note"><h3>Note</h3> + <p>Domain name comparisons are done without regard to the case, and + <var>Domain</var>s are always assumed to be anchored in the root of the + DNS tree; therefore, the two domains <code>.ExAmple.com</code> and + <code>.example.com.</code> (note the trailing period) are considered + equal. Since a domain comparison does not involve a DNS lookup, it is much + more efficient than subnet comparison.</p> + </div></dd> + + + <dt><var><a name="subnet" id="subnet">SubNet</a></var></dt> + <dd> + <p>A <dfn>SubNet</dfn> is a partially qualified internet address in + numeric (dotted quad) form, optionally followed by a slash and the netmask, + specified as the number of significant bits in the <var>SubNet</var>. It is + used to represent a subnet of hosts which can be reached over a common + network interface. In the absence of the explicit net mask it is assumed + that omitted (or zero valued) trailing digits specify the mask. (In this + case, the netmask can only be multiples of 8 bits wide.) Examples:</p> + + <dl> + <dt><code>192.168</code> or <code>192.168.0.0</code></dt> + <dd>the subnet 192.168.0.0 with an implied netmask of 16 valid bits + (sometimes used in the netmask form <code>255.255.0.0</code>)</dd> + <dt><code>192.168.112.0/21</code></dt> + <dd>the subnet <code>192.168.112.0/21</code> with a netmask of 21 + valid bits (also used in the form <code>255.255.248.0</code>)</dd> + </dl> + + <p>As a degenerate case, a <em>SubNet</em> with 32 valid bits is the + equivalent to an <var><a href="#ipaddr">IPAddr</a></var>, while a <var>SubNet</var> with zero + valid bits (<em>e.g.</em>, 0.0.0.0/0) is the same as the constant + <var>_Default_</var>, matching any IP address.</p></dd> + + + <dt><var><a name="ipaddr" id="ipaddr">IPAddr</a></var></dt> + <dd> + <p>A <dfn>IPAddr</dfn> represents a fully qualified internet address in + numeric (dotted quad) form. Usually, this address represents a host, but + there need not necessarily be a DNS domain name connected with the + address.</p> + <div class="example"><h3>Example</h3><p><code> + 192.168.123.7 + </code></p></div> + + <div class="note"><h3>Note</h3> + <p>An <var>IPAddr</var> does not need to be resolved by the DNS system, so + it can result in more effective apache performance.</p> + </div></dd> + + + <dt><var><a name="hostname" id="hostname">Hostname</a></var></dt> + <dd> + <p>A <dfn>Hostname</dfn> is a fully qualified DNS domain name which can + be resolved to one or more <var><a href="#ipaddr">IPAddrs</a></var> via the + DNS domain name service. It represents a logical host (in contrast to + <var><a href="#domain">Domain</a></var>s, see above) and must be resolvable + to at least one <var><a href="#ipaddr">IPAddr</a></var> (or often to a list + of hosts with different <var><a href="#ipaddr">IPAddr</a></var>s).</p> + + <div class="example"><h3>Examples</h3><p><code> + prep.ai.example.edu<br /> + www.example.org + </code></p></div> + + <div class="note"><h3>Note</h3> + <p>In many situations, it is more effective to specify an <var><a href="#ipaddr">IPAddr</a></var> in place of a <var>Hostname</var> since a + DNS lookup can be avoided. Name resolution in Apache httpd can take a remarkable + deal of time when the connection to the name server uses a slow PPP + link.</p> + <p><var>Hostname</var> comparisons are done without regard to the case, + and <var>Hostname</var>s are always assumed to be anchored in the root + of the DNS tree; therefore, the two hosts <code>WWW.ExAmple.com</code> + and <code>www.example.com.</code> (note the trailing period) are + considered equal.</p> + </div></dd> + </dl> + +<h3>See also</h3> +<ul> +<li><a href="../dns-caveats.html">DNS Issues</a></li> +</ul> +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="Proxy" id="Proxy"><Proxy></a> <a name="proxy" id="proxy">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Container for directives applied to proxied resources</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Proxy <var>wildcard-url</var>> ...</Proxy></code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +</table> + <p>Directives placed in <code class="directive"><Proxy></code> + sections apply only to matching proxied content. Shell-style wildcards are + allowed.</p> + + <p>For example, the following will allow only hosts in + <code>yournetwork.example.com</code> to access content via your proxy + server:</p> + + <pre class="prettyprint lang-config"><Proxy "*"> + Require host yournetwork.example.com +</Proxy></pre> + + + <p>The following example will process all files in the <code>foo</code> + directory of <code>example.com</code> through the <code>INCLUDES</code> + filter when they are sent through the proxy server:</p> + + <pre class="prettyprint lang-config"><Proxy "http://example.com/foo/*"> + SetOutputFilter INCLUDES +</Proxy></pre> + + + <div class="note"><h3>Differences from the Location configuration section</h3> + <p>A backend URL matches the configuration section if it begins with the + the <var>wildcard-url</var> string, even if the last path segment in the + directive only matches a prefix of the backend URL. For example, + <Proxy "http://example.com/foo"> matches all of + http://example.com/foo, http://example.com/foo/bar, and + http://example.com/foobar. The matching of the final URL differs + from the behavior of the <code class="directive"><a href="../mod/core.html#location"><Location></a></code> section, which for purposes of this note + treats the final path component as if it ended in a slash.</p> + <p>For more control over the matching, see <code class="directive"><ProxyMatch></code>.</p> + </div> + + +<h3>See also</h3> +<ul> +<li><code class="directive"><a href="#proxymatch"><ProxyMatch></a></code></li> +</ul> +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="Proxy100Continue" id="Proxy100Continue">Proxy100Continue</a> <a name="proxy100continue" id="proxy100continue">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Forward 100-continue expectation to the origin server</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Proxy100Continue Off|On</code></td></tr> +<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Proxy100Continue On</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in version 2.4.40 and later</td></tr> +</table> + <p>This directive determines whether the proxy should forward 100-continue + <em>Expect:</em>ation to the origin server and thus let it decide when/if + the HTTP request body should be read, or when <code>Off</code> the proxy + should generate <em>100 Continue</em> intermediate response by itself before + forwarding the request body.</p> + <div class="note"><h3>Effectiveness</h3> + <p>This option is of use only for HTTP proxying, as handled by <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code>.</p> + </div> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyAddHeaders" id="ProxyAddHeaders">ProxyAddHeaders</a> <a name="proxyaddheaders" id="proxyaddheaders">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Add proxy information in X-Forwarded-* headers</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyAddHeaders Off|On</code></td></tr> +<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyAddHeaders On</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in version 2.3.10 and later</td></tr> +</table> + <p>This directive determines whether or not proxy related information should be passed to the + backend server through X-Forwarded-For, X-Forwarded-Host and X-Forwarded-Server HTTP headers.</p> + <div class="note"><h3>Effectiveness</h3> + <p>This option is of use only for HTTP proxying, as handled by <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code>.</p> + </div> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyBadHeader" id="ProxyBadHeader">ProxyBadHeader</a> <a name="proxybadheader" id="proxybadheader">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines how to handle bad header lines in a +response</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyBadHeader IsError|Ignore|StartBody</code></td></tr> +<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyBadHeader IsError</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +</table> + <p>The <code class="directive">ProxyBadHeader</code> directive determines the + behavior of <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> if it receives syntactically invalid + response header lines (<em>i.e.</em> containing no colon) from the origin + server. The following arguments are possible:</p> + + <dl> + <dt><code>IsError</code></dt> + <dd>Abort the request and end up with a 502 (Bad Gateway) response. This is + the default behavior.</dd> + + <dt><code>Ignore</code></dt> + <dd>Treat bad header lines as if they weren't sent.</dd> + + <dt><code>StartBody</code></dt> + <dd>When receiving the first bad header line, finish reading the headers and + treat the remainder as body. This helps to work around buggy backend servers + which forget to insert an empty line between the headers and the body.</dd> + </dl> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyBlock" id="ProxyBlock">ProxyBlock</a> <a name="proxyblock" id="proxyblock">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Words, hosts, or domains that are banned from being +proxied</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyBlock *|<var>word</var>|<var>host</var>|<var>domain</var> +[<var>word</var>|<var>host</var>|<var>domain</var>] ...</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +</table> + <p>The <code class="directive">ProxyBlock</code> directive specifies a list of + words, hosts and/or domains, separated by spaces. HTTP, HTTPS, and + FTP document requests to sites whose names contain matched words, + hosts or domains are <em>blocked</em> by the proxy server. The proxy + module will also attempt to determine IP addresses of list items which + may be hostnames during startup, and cache them for match test as + well. That may slow down the startup time of the server.</p> + + <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">ProxyBlock "news.example.com" "auctions.example.com" "friends.example.com"</pre> +</div> + + <p>Note that <code>example</code> would also be sufficient to match any + of these sites.</p> + + <p>Hosts would also be matched if referenced by IP address.</p> + + <p>Note also that</p> + + <pre class="prettyprint lang-config">ProxyBlock "*"</pre> + + + <p>blocks connections to all sites.</p> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyDomain" id="ProxyDomain">ProxyDomain</a> <a name="proxydomain" id="proxydomain">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Default domain name for proxied requests</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyDomain <var>Domain</var></code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +</table> + <p>This directive is only useful for Apache httpd proxy servers within + intranets. The <code class="directive">ProxyDomain</code> directive specifies + the default domain which the apache proxy server will belong to. If a + request to a host without a domain name is encountered, a redirection + response to the same host with the configured <var>Domain</var> appended + will be generated.</p> + + <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">ProxyRemote "*" "http://firewall.example.com:81" +NoProxy ".example.com" "192.168.112.0/21" +ProxyDomain ".example.com"</pre> +</div> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyErrorOverride" id="ProxyErrorOverride">ProxyErrorOverride</a> <a name="proxyerroroverride" id="proxyerroroverride">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Override error pages for proxied content</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyErrorOverride Off|On [<var>code</var> ...]</code></td></tr> +<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyErrorOverride Off</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>The list of status codes was added in 2.4.47</td></tr> +</table> + <p>This directive is useful for reverse-proxy setups where you want to + have a common look and feel on the error pages seen by the end user. + This also allows for included files (via + <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>'s SSI) to get + the error code and act accordingly. (Default behavior would display + the error page of the proxied server. Turning this on shows the SSI + Error message.)</p> + + <p>This directive does not affect the processing of informational (1xx), + normal success (2xx), or redirect (3xx) responses.</p> + + <p>By default <code class="directive">ProxyErrorOverride</code> affects all responses with codes between 400 (including) + and 600 (excluding).</p> + + <div class="example"><h3>Example for default behavior</h3><pre class="prettyprint lang-config">ProxyErrorOverride On</pre> +</div> + + <p>To change the default behavior, you can specify the status codes to consider, separated by spaces. + If you do so, all other status codes will be ignored. + You can only specify status codes, that are considered error codes: between 400 (including) + and 600 (excluding).</p> + + <div class="example"><h3>Example for custom status codes</h3><pre class="prettyprint lang-config">ProxyErrorOverride On 403 405 500 501 502 503 504</pre> +</div> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyIOBufferSize" id="ProxyIOBufferSize">ProxyIOBufferSize</a> <a name="proxyiobuffersize" id="proxyiobuffersize">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine size of internal data throughput buffer</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyIOBufferSize <var>bytes</var></code></td></tr> +<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyIOBufferSize 8192</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +</table> + <p>The <code class="directive">ProxyIOBufferSize</code> directive adjusts the size + of the internal buffer which is used as a scratchpad for the data between + input and output. The size must be at least <code>512</code>.</p> + + <p>In almost every case, there's no reason to change that value.</p> + + <p>If used with AJP, this directive sets the maximum AJP packet size in + bytes. Values larger than 65536 are set to 65536. If you change it from + the default, you must also change the <code>packetSize</code> attribute of + your AJP connector on the Tomcat side! The attribute + <code>packetSize</code> is only available in Tomcat <code>5.5.20+</code> + and <code>6.0.2+</code></p> + + <p>Normally it is not necessary to change the maximum packet size. + Problems with the default value have been reported when sending + certificates or certificate chains.</p> + + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyMatch" id="ProxyMatch"><ProxyMatch></a> <a name="proxymatch" id="proxymatch">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Container for directives applied to regular-expression-matched +proxied resources</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><ProxyMatch <var>regex</var>> ...</ProxyMatch></code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +</table> + <p>The <code class="directive"><ProxyMatch></code> directive is + identical to the <code class="directive"><a href="#proxy"><Proxy></a></code> directive, except that it matches URLs + using <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expressions</a>.</p> + + <p>From 2.4.8 onwards, named groups and backreferences are captured and + written to the environment with the corresponding name prefixed with + "MATCH_" and in upper case. This allows elements of URLs to be referenced + from within <a href="../expr.html">expressions</a> and modules like + <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. In order to prevent confusion, numbered + (unnamed) backreferences are ignored. Use named groups instead.</p> + +<pre class="prettyprint lang-config"><ProxyMatch "^http://(?<sitename>[^/]+)"> + Require ldap-group cn=%{env:MATCH_SITENAME},ou=combined,o=Example +</ProxyMatch></pre> + + +<h3>See also</h3> +<ul> +<li><code class="directive"><a href="#proxy"><Proxy></a></code></li> +</ul> +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyMaxForwards" id="ProxyMaxForwards">ProxyMaxForwards</a> <a name="proxymaxforwards" id="proxymaxforwards">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximum number of proxies that a request can be forwarded +through</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyMaxForwards <var>number</var></code></td></tr> +<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyMaxForwards -1</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Default behaviour changed in 2.2.7</td></tr> +</table> + <p>The <code class="directive">ProxyMaxForwards</code> directive specifies the + maximum number of proxies through which a request may pass if there's no + <code>Max-Forwards</code> header supplied with the request. This may + be set to prevent infinite proxy loops or a DoS attack.</p> + + <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">ProxyMaxForwards 15</pre> +</div> + + <p>Note that setting <code class="directive">ProxyMaxForwards</code> is a + violation of the HTTP/1.1 protocol (RFC2616), which forbids a Proxy + setting <code>Max-Forwards</code> if the Client didn't set it. + Earlier Apache httpd versions would always set it. A negative + <code class="directive">ProxyMaxForwards</code> value, including the + default -1, gives you protocol-compliant behavior but may + leave you open to loops.</p> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyPass" id="ProxyPass">ProxyPass</a> <a name="proxypass" id="proxypass">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maps remote servers into the local server URL-space</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPass [<var>path</var>] !|<var>url</var> [<var>key=value</var> + <var>[key=value</var> ...]] [nocanon] [interpolate] [noquery]</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Unix Domain Socket (UDS) support added in 2.4.7</td></tr> +</table> + <p>This directive allows remote servers to be mapped into the + space of the local server. The local server does not act as a + proxy in the conventional sense but appears to be a mirror of the + remote server. The local server is often called a <dfn>reverse + proxy</dfn> or <dfn>gateway</dfn>. The <var>path</var> is the name of + a local virtual path; <var>url</var> is a partial URL for the + remote server and cannot include a query string.</p> + + <div class="note">It is strongly suggested to review the concept of a + <a href="#workers">Worker</a> before proceeding any further + with this section.</div> + + <div class="note">This directive is not supported within + <code class="directive"><a href="../mod/core.html#directory"><Directory></a></code>, + <code class="directive"><a href="../mod/core.html#if"><If></a></code> and + <code class="directive"><a href="../mod/core.html#files"><Files></a></code> containers. + </div> + + <div class="warning">The <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> directive should + usually be set <strong>off</strong> when using + <code class="directive">ProxyPass</code>.</div> + + <p>In 2.4.7 and later, support for using a Unix Domain Socket is available by using a target + which prepends <code>unix:/path/lis.sock|</code>. For example, to proxy + HTTP and target the UDS at /home/www.socket, you would use + <code>unix:/home/www.socket|http://localhost/whatever/</code>.</p> + + <div class="note"><strong>Note:</strong> The path associated with the <code>unix:</code> + URL is <code class="directive">DefaultRuntimeDir</code> aware.</div> + + <p>When used inside a <code class="directive"><a href="../mod/core.html#location"><Location></a></code> section, the first argument is omitted and the local + directory is obtained from the <code class="directive"><a href="../mod/core.html#location"><Location></a></code>. The same will occur inside a + <code class="directive"><a href="../mod/core.html#locationmatch"><LocationMatch></a></code> section; + however, ProxyPass does not interpret the regexp as such, so it is necessary + to use <code class="directive">ProxyPassMatch</code> in this situation instead.</p> + + <p>Suppose the local server has address <code>http://example.com/</code>; + then</p> + + <pre class="prettyprint lang-config"><Location "/mirror/foo/"> + ProxyPass "http://backend.example.com/" +</Location></pre> + + + <p>will cause a local request for + <code>http://example.com/mirror/foo/bar</code> to be internally converted + into a proxy request to <code>http://backend.example.com/bar</code>.</p> + + <p>If you require a more flexible reverse-proxy configuration, see the + <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> directive with the + <code>[P]</code> flag.</p> + + <p>The following alternative syntax is possible; however, it can carry a + performance penalty when present in very large numbers. The advantage of + the below syntax is that it allows for dynamic control via the + <a href="mod_proxy_balancer.html#balancer_manager">Balancer Manager</a> interface:</p> + + <pre class="prettyprint lang-config">ProxyPass "/mirror/foo/" "http://backend.example.com/"</pre> + + + <div class="warning"> + <p>If the first argument ends with a trailing <strong>/</strong>, the second + argument should also end with a trailing <strong>/</strong>, and vice + versa. Otherwise, the resulting requests to the backend may miss some + needed slashes and do not deliver the expected results. + </p> + </div> + + <p>The <code>!</code> directive is useful in situations where you don't want + to reverse-proxy a subdirectory, <em>e.g.</em></p> + + <pre class="prettyprint lang-config"><Location "/mirror/foo/"> + ProxyPass "http://backend.example.com/" +</Location> +<Location "/mirror/foo/i"> + ProxyPass "!" +</Location></pre> + + + <pre class="prettyprint lang-config">ProxyPass "/mirror/foo/i" "!" +ProxyPass "/mirror/foo" "http://backend.example.com"</pre> + + + <p>will proxy all requests to <code>/mirror/foo</code> to + <code>backend.example.com</code> <em>except</em> requests made to + <code>/mirror/foo/i</code>.</p> + + <p>Mixing ProxyPass settings in different contexts does not work:</p> + <pre class="prettyprint lang-config">ProxyPass "/mirror/foo/i" "!" +<Location "/mirror/foo/"> + ProxyPass "http://backend.example.com/" +</Location></pre> + + <p>In this case, a request to <code>/mirror/foo/i</code> will get proxied, + because the <code class="directive">ProxyPass</code> directive in the Location block will be evaluated + first. The fact that <code class="directive">ProxyPass</code> supports both server and directory contexts + does not mean that their scope and position in the configuration file will + guarantee any ordering or override.</p> + + <div class="warning"><h3>Ordering ProxyPass Directives</h3> + <p>The configured <code class="directive"><a href="#proxypass">ProxyPass</a></code> + and <code class="directive"><a href="#proxypassmatch">ProxyPassMatch</a></code> + rules are checked in the order of configuration. The first rule that + matches wins. So usually you should sort conflicting + <code class="directive"><a href="#proxypass">ProxyPass</a></code> rules starting with the + longest URLs first. Otherwise, later rules for longer URLS will be hidden + by any earlier rule which uses a leading substring of the URL. Note that + there is some relation with worker sharing.</p> + </div> + <div class="warning"><h3>Ordering ProxyPass Directives in Locations</h3> + <p>Only one <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive + can be placed in a <code class="directive"><a href="../mod/core.html#location">Location</a></code> block, + and the most specific location will take precedence.</p> + </div> + <div class="warning"><h3>Exclusions and the no-proxy environment variable</h3> + <p>Exclusions must come <em>before</em> the + general <code class="directive">ProxyPass</code> directives. In 2.4.26 and later, the "no-proxy" + environment variable is an alternative to exclusions, and is the only + way to configure an exclusion of a <code class="directive">ProxyPass</code> + directive in <code class="directive"><a href="../mod/core.html#location">Location</a></code> context. + This variable should be set with <code class="directive"><a href="../mod/mod_setenvif.html#setenvif">SetEnvIf</a></code>, as <code class="directive"><a href="../mod/mod_env.html#setenv">SetEnv</a></code> + is not evaluated early enough. + </p> + + </div> + + <p><strong>ProxyPass <code>key=value</code> Parameters</strong></p> + + <p>In Apache HTTP Server 2.1 and later, mod_proxy supports pooled + connections to a backend server. Connections created on demand + can be retained in a pool for future use. Limits on the pool size + and other settings can be coded on + the <code class="directive">ProxyPass</code> directive + using <code>key=value</code> parameters, described in the tables + below.</p> + + <div class="warning"><h3>Maximum connections to the backend</h3> + <p>By default, mod_proxy will allow and retain the maximum number of + connections that could be used simultaneously by that web server child + process. Use the <code>max</code> parameter to reduce the number from + the default. The pool of connections is maintained per web server child + process, and <code>max</code> and other settings are not coordinated + among all child processes, except when only one child process is allowed + by configuration or MPM design.</p> + </div> + + <p>Use the <code>ttl</code> parameter to set an optional + time to live; connections which have been unused for at least + <code>ttl</code> seconds will be closed. <code>ttl</code> can be used + to avoid using a connection which is subject to closing because of the + backend server's keep-alive timeout.</p> + + <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">ProxyPass "/example" "http://backend.example.com" max=20 ttl=120 retry=300</pre> +</div> + + <table class="bordered"><tr><th>Worker|BalancerMember parameters</th></tr></table> + <table> + <tr><th>Parameter</th> + <th>Default</th> + <th>Description</th></tr> + <tr><td>min</td> + <td>0</td> + <td>Minimum number of connection pool entries, unrelated to the + actual number of connections. This only needs to be modified from the + default for special circumstances where heap memory associated with the + backend connections should be preallocated or retained.</td></tr> + <tr><td>max</td> + <td>1...n</td> + <td>Maximum number of connections that will be allowed to the + backend server. The default for this limit is the number of threads + per process in the active MPM. In the Prefork MPM, this is always 1, + while with other MPMs, it is controlled by the + <code class="directive">ThreadsPerChild</code> directive.</td></tr> + <tr><td>smax</td> + <td>max</td> + <td>Retained connection pool entries above this limit are freed + during certain operations if they have been unused for longer than + the time to live, controlled by the <code>ttl</code> parameter. If + the connection pool entry has an associated connection, it will be + closed. This only needs to be modified from the default for special + circumstances where connection pool entries and any associated + connections which have exceeded the time to live need to be freed or + closed more aggressively.</td></tr> + <tr><td>acquire</td> + <td>-</td> + <td>If set, this will be the maximum time to wait for a free + connection in the connection pool, in milliseconds. If there are no free + connections in the pool, the Apache httpd will return <code>SERVER_BUSY</code> + status to the client. + </td></tr> + <tr><td>connectiontimeout</td> + <td>timeout</td> + <td>Connect timeout in seconds. + The number of seconds Apache httpd waits for the creation of a connection to + the backend to complete. By adding a postfix of ms, the timeout can be + also set in milliseconds. + </td></tr> + <tr><td>disablereuse</td> + <td>Off</td> + <td>This parameter should be used when you want to force mod_proxy + to immediately close a connection to the backend after being used, and + thus, disable its persistent connection and pool for that backend. + This helps in various situations where a firewall between Apache + httpd and + the backend server (regardless of protocol) tends to silently + drop connections or when backends themselves may be under round- + robin DNS. + When connection reuse is enabled each backend domain is resolved + (with a DNS query) only once per child process and cached for all further + connections until the child is recycled. To disable connection reuse, + set this property value to <code>On</code>. + </td></tr> + <tr><td>enablereuse</td> + <td>On</td> + <td>This is the inverse of 'disablereuse' above, provided as a + convenience for scheme handlers that require opt-in for connection + reuse (such as <code class="module"><a href="../mod/mod_proxy_fcgi.html">mod_proxy_fcgi</a></code>). 2.4.11 and later only. + </td></tr> + <tr><td>flushpackets</td> + <td>off</td> + <td>Determines whether the proxy module will auto-flush the output + brigade after each "chunk" of data. 'off' means that it will flush + only when needed; 'on' means after each chunk is sent; and + 'auto' means poll/wait for a period of time and flush if + no input has been received for 'flushwait' milliseconds. + Currently, this is in effect only for mod_proxy_ajp and mod_proxy_fcgi. + </td></tr> + <tr><td>flushwait</td> + <td>10</td> + <td>The time to wait for additional input, in milliseconds, before + flushing the output brigade if 'flushpackets' is 'auto'. + </td></tr> + <tr><td>iobuffersize</td> + <td>8192</td> + <td>Adjusts the size of the internal scratchpad IO buffer. This allows you + to override the <code class="directive">ProxyIOBufferSize</code> for a specific worker. + This must be at least 512 or set to 0 for the system default of 8192. + </td></tr> + <tr><td>responsefieldsize</td> + <td>8192</td> + <td>Adjust the size of the proxy response field buffer. The buffer size + should be at least the size of the largest expected header size from + a proxied response. Setting the value to 0 will use the system + default of 8192 bytes.<br /> + Available in Apache HTTP Server 2.4.34 and later. + </td></tr> + <tr><td>keepalive</td> + <td>Off</td> + <td><p>This parameter should be used when you have a firewall between your + Apache httpd and the backend server, which tends to drop inactive connections. + This flag will tell the Operating System to send <code>KEEP_ALIVE</code> + messages on inactive connections and thus prevent the firewall from dropping + the connection. + To enable keepalive, set this property value to <code>On</code>. </p> + <p>The frequency of initial and subsequent TCP keepalive probes + depends on global OS settings, and may be as high as 2 hours. To be useful, + the frequency configured in the OS must be smaller than the threshold used + by the firewall.</p> + </td></tr> + <tr><td>lbset</td> + <td>0</td> + <td>Sets the load balancer cluster set that the worker is a member + of. The load balancer will try all members of a lower numbered + lbset before trying higher numbered ones. + </td></tr> + <tr><td>ping</td> + <td>0</td> + <td>Ping property tells the webserver to "test" the connection to + the backend before forwarding the request. For AJP, it causes + <code class="module"><a href="../mod/mod_proxy_ajp.html">mod_proxy_ajp</a></code> to send a <code>CPING</code> + request on the ajp13 connection (implemented on Tomcat 3.3.2+, 4.1.28+ + and 5.0.13+). For HTTP, it causes <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code> + to send a <code>100-Continue</code> to the backend (only valid for + HTTP/1.1 - for non HTTP/1.1 backends, this property has no + effect). In both cases, the parameter is the delay in seconds to wait + for the reply. + This feature has been added to avoid problems with hung and + busy backends. + This will increase the network traffic during the normal operation + which could be an issue, but it will lower the + traffic in case some of the cluster nodes are down or busy. + By adding a postfix of ms, the delay can be also set in + milliseconds. + </td></tr> + <tr><td>receivebuffersize</td> + <td>0</td> + <td>Adjusts the size of the explicit (TCP/IP) network buffer size for + proxied connections. This allows you to override the + <code class="directive">ProxyReceiveBufferSize</code> for a specific worker. + This must be at least 512 or set to 0 for the system default. + </td></tr> + <tr><td>redirect</td> + <td>-</td> + <td>Redirection Route of the worker. This value is usually + set dynamically to enable safe removal of the node from + the cluster. If set, all requests without session id will be + redirected to the BalancerMember that has route parameter + equal to this value. + </td></tr> + <tr><td>retry</td> + <td>60</td> + <td>Connection pool worker retry timeout in seconds. + If the connection pool worker to the backend server is in the error state, + Apache httpd will not forward any requests to that server until the timeout + expires. This enables to shut down the backend server for maintenance + and bring it back online later. A value of 0 means always retry workers + in an error state with no timeout. + </td></tr> + <tr><td>route</td> + <td>-</td> + <td>Route of the worker when used inside load balancer. + The route is a value appended to session id. + </td></tr> + <tr><td><a name="status_table">status</a></td> + <td>-</td> + <td>Single letter value defining the initial status of + this worker. + <table> + <tr><td>D: Worker is disabled and will not accept any requests.</td></tr> + <tr><td>S: Worker is administratively stopped.</td></tr> + <tr><td>I: Worker is in ignore-errors mode and will always be considered available.</td></tr> + <tr><td>R: Worker is a hot spare. For each worker in a given lbset that is unusable + (draining, stopped, in error, etc.), a usable hot spare with the same lbset will be used in + its place. Hot spares can help ensure that a specific number of workers are always available + for use by a balancer.</td></tr> + <tr><td>H: Worker is in hot-standby mode and will only be used if no other + viable workers or spares are available in the balancer set.</td></tr> + <tr><td>E: Worker is in an error state.</td></tr> + <tr><td>N: Worker is in drain mode and will only accept existing sticky sessions + destined for itself and ignore all other requests.</td></tr> + </table>Status + can be set (which is the default) by prepending with '+' or + cleared by prepending with '-'. + Thus, a setting of 'S-E' sets this worker to Stopped and + clears the in-error flag. + </td></tr> + <tr><td>timeout</td> + <td><code class="directive"><a href="#proxytimeout">ProxyTimeout</a></code></td> + <td>Connection timeout in seconds. + The number of seconds Apache httpd waits for data sent by / to the backend. + </td></tr> + <tr><td>ttl</td> + <td>-</td> + <td>Time to live for inactive connections and associated connection + pool entries, in seconds. Once reaching this limit, a + connection will not be used again; it will be closed at some + later time. + </td></tr> + <tr><td>flusher</td> + <td>flush</td> + <td><p>Name of the provider used by <code class="module"><a href="../mod/mod_proxy_fdpass.html">mod_proxy_fdpass</a></code>. + See the documentation of this module for more details.</p> + </td></tr> + <tr><td>secret</td> + <td>-</td> + <td>Value of secret used by <code class="module"><a href="../mod/mod_proxy_ajp.html">mod_proxy_ajp</a></code>. + It must be identical to the secret configured on the server side of the + AJP connection.<br /> + Available in Apache HTTP Server 2.4.42 and later. + </td></tr> + <tr><td><a id="upgrade" name="upgrade">upgrade</a></td> + <td>-</td> + <td><p>Protocol accepted by <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code> or + <code class="module"><a href="../mod/mod_proxy_wstunnel.html">mod_proxy_wstunnel</a></code> for the HTTP Upgrade mechanism + upon negotiation by the HTTP client/browser (per + <a href="https://www.ietf.org/rfc/rfc9110.html#name-upgrade">RFC 9110 - Upgrade</a>). + See the <a href="#protoupgrade">Protocol Upgrade</a> note below</p> + </td></tr> + <tr><td>mapping</td> + <td>-</td> + <td><p>Type of mapping between the <var>path</var> and the <var>url</var>. + This determines the normalization and/or (non-)decoding that <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> + will apply to the requested <var>uri-path</var> before matching the <var>path</var>. If + a mapping matches, it's committed to the <var>uri-path</var> such that all the directory + contexts that use a path (like <code><Location></code>) will be matched using the + same mapping.</p> + <p><code>mapping=encoded</code> prevents the %-decoding of the <var>uri-path</var> so + that one can use for instance configurations like:</p> + <pre class="prettyprint lang-config">ProxyPass "/special%3Fsegment" "https://example.com/special%3Fsegment" mapping=encoded</pre> + + <pre class="prettyprint lang-config"><Location "/special%3Fsegment"> + Require ip 172.17.2.0/24 +</Location></pre> + + <p><code>mapping=servlet</code> refers to the normalization defined by the Servlet + specification, which is for instance applied by Apache Tomcat for servlet containers + (notably the path parameters are ignored for the mapping). An <var>uri-path</var> like + <code>/some;foo/path</code> is then mapped as <code>/some/path</code> hence matches any + of the below regardless of the requested path parameters:</p> + <pre class="prettyprint lang-config">ProxyPass "/some/path" "https://servlet.example.com/some/path" mapping=servlet</pre> + + <pre class="prettyprint lang-config"><Location "/some/path"> + Require valid-user +</Location></pre> + + <div class="note"><h3>Note</h3> + <p>It is recommended to use the same mapping on the Apache httpd side than the one + used on the backend side. For instance when configuring authorizations in + <code><Location></code> blocks for paths that are mapped by <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> + to some servlet containers (like applications running on Apache Tomcat), one should + use the <code>mapping=servlet</code> setting to prevent path parameters and alike from + interfering with the authorizations that are to be enforced in by the Apache httpd.</p> + </div> + </td></tr> + + </table> + + <p>If the Proxy directive scheme starts with the + <code>balancer://</code> (eg: <code>balancer://cluster</code>, + any path information is ignored), then a virtual worker that does not really + communicate with the backend server will be created. Instead, it is responsible + for the management of several "real" workers. In that case, the special set of + parameters can be added to this virtual worker. + See <code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code> for more information about how + the balancer works. + </p> + <table class="bordered"><tr><th>Balancer parameters</th></tr></table> + <table> + <tr><th>Parameter</th> + <th>Default</th> + <th>Description</th></tr> + <tr><td>lbmethod</td> + <td>byrequests</td> + <td>Balancer load-balance method. Select the load-balancing scheduler + method to use. Either <code>byrequests</code>, to perform weighted + request counting; <code>bytraffic</code>, to perform weighted + traffic byte count balancing; or <code>bybusyness</code>, to perform + pending request balancing. The default is <code>byrequests</code>. + </td></tr> + <tr><td>maxattempts</td> + <td>One less than the number of workers, or 1 with a single worker.</td> + <td>Maximum number of failover attempts before giving up. + </td></tr> + <tr><td>nofailover</td> + <td>Off</td> + <td>If set to <code>On</code>, the session will break if the worker is in + error state or disabled. Set this value to <code>On</code> if backend + servers do not support session replication. + </td></tr> + <tr><td>stickysession</td> + <td>-</td> + <td>Balancer sticky session name. The value is usually set to something + like <code>JSESSIONID</code> or <code>PHPSESSIONID</code>, + and it depends on the backend application server that support sessions. + If the backend application server uses different name for cookies + and url encoded id (like servlet containers) use | to separate them. + The first part is for the cookie the second for the path.<br /> + Available in Apache HTTP Server 2.4.4 and later. + </td></tr> + <tr><td>stickysessionsep</td> + <td>"."</td> + <td>Sets the separation symbol in the session cookie. Some backend application servers + do not use the '.' as the symbol. For example, the Oracle Weblogic server uses + '!'. The correct symbol can be set using this option. The setting of 'Off' + signifies that no symbol is used. + </td></tr> + <tr><td>scolonpathdelim</td> + <td>Off</td> + <td>If set to <code>On</code>, the semi-colon character ';' will be + used as an additional sticky session path delimiter/separator. This + is mainly used to emulate mod_jk's behavior when dealing with paths such + as <code>JSESSIONID=6736bcf34;foo=aabfa</code> + </td></tr> + <tr><td>timeout</td> + <td>0</td> + <td>Balancer timeout in seconds. If set, this will be the maximum time + to wait for a free worker. The default is to not wait. + </td></tr> + <tr><td>failonstatus</td> + <td>-</td> + <td>A single or comma-separated list of HTTP status codes. If set, this will + force the worker into error state when the backend returns any status code + in the list. Worker recovery behaves the same as other worker errors. + </td></tr> + <tr><td>failontimeout</td> + <td>Off</td> + <td>If set, an IO read timeout after a request is sent to the backend will + force the worker into error state. Worker recovery behaves the same as other + worker errors.<br /> + Available in Apache HTTP Server 2.4.5 and later. + </td></tr> + <tr><td>nonce</td> + <td><auto></td> + <td>The protective nonce used in the <code>balancer-manager</code> application page. + The default is to use an automatically determined UUID-based + nonce, to provide for further protection for the page. If set, + then the nonce is set to that value. A setting of <code>None</code> + disables all nonce checking. + <div class="note"><h3>Note</h3> + <p>In addition to the nonce, the <code>balancer-manager</code> page + should be protected via an ACL.</p> + </div> + </td></tr> + <tr><td>growth</td> + <td>0</td> + <td>Number of additional BalancerMembers to allow to be added + to this balancer in addition to those defined at configuration. + </td></tr> + <tr><td>forcerecovery</td> + <td>On</td> + <td>Force the immediate recovery of all workers without considering the + retry parameter of the workers if all workers of a balancer are + in error state. There might be cases where an already overloaded backend + can get into deeper trouble if the recovery of all workers is enforced + without considering the retry parameter of each worker. In this case, + set to <code>Off</code>.<br /> + Available in Apache HTTP Server 2.4.2 and later. + </td></tr> + + </table> + <p>A sample balancer setup:</p> + <pre class="prettyprint lang-config">ProxyPass "/special-area" "http://special.example.com" smax=5 max=10 +ProxyPass "/" "balancer://mycluster/" stickysession=JSESSIONID|jsessionid nofailover=On +<Proxy "balancer://mycluster"> + BalancerMember "ajp://1.2.3.4:8009" + BalancerMember "ajp://1.2.3.5:8009" loadfactor=20 + # Less powerful server, don't send as many requests there, + BalancerMember "ajp://1.2.3.6:8009" loadfactor=5 +</Proxy></pre> + + + <p>Configuring hot spares can help ensure that a certain number of + workers are always available for use per load balancer set:</p> + <pre class="prettyprint lang-config">ProxyPass "/" "balancer://sparecluster/" +<Proxy balancer://sparecluster> + BalancerMember ajp://1.2.3.4:8009 + BalancerMember ajp://1.2.3.5:8009 + # The servers below are hot spares. For each server above that is unusable + # (draining, stopped, unreachable, in error state, etc.), one of these spares + # will be used in its place. Two servers will always be available for a request + # unless one or more of the spares is also unusable. + BalancerMember ajp://1.2.3.6:8009 status=+R + BalancerMember ajp://1.2.3.7:8009 status=+R +</Proxy></pre> + + + <p>Setting up a hot-standby that will only be used if no other + members (or spares) are available in the load balancer set:</p> + <pre class="prettyprint lang-config">ProxyPass "/" "balancer://hotcluster/" +<Proxy "balancer://hotcluster"> + BalancerMember "ajp://1.2.3.4:8009" loadfactor=1 + BalancerMember "ajp://1.2.3.5:8009" loadfactor=2.25 + # The server below is on hot standby + BalancerMember "ajp://1.2.3.6:8009" status=+H + ProxySet lbmethod=bytraffic +</Proxy></pre> + + + <p><strong>Additional ProxyPass Keywords</strong></p> + + <p>Normally, mod_proxy will canonicalise ProxyPassed URLs. + But this may be incompatible with some backends, particularly those + that make use of <var>PATH_INFO</var>. The optional <var>nocanon</var> + keyword suppresses this and passes the URL path "raw" to the + backend. Note that this keyword may affect the security of your backend, + as it removes the normal limited protection against URL-based attacks + provided by the proxy.</p> + + <p>Normally, mod_proxy will include the query string when + generating the <var>SCRIPT_FILENAME</var> environment variable. + The optional <var>noquery</var> keyword (available in + httpd 2.4.1 and later) prevents this.</p> + + <p>The optional <code>interpolate</code> keyword, in combination with + <code class="directive"><a href="#proxypassinterpolateenv">ProxyPassInterpolateEnv</a></code>, causes the ProxyPass + to interpolate environment variables, using the syntax + <var>${VARNAME}</var>. Note that many of the standard CGI-derived + environment variables will not exist when this interpolation happens, + so you may still have to resort to <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> + for complex rules. Also note that interpolation is supported + within the scheme/hostname/port portion of a URL only for variables that + are available when the directive is parsed + (like <code class="directive"><a href="../mod/core.html#define">Define</a></code>). Dynamic determination of + those fields can be accomplished with <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. + The following example describes how to use <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> + to dynamically set the scheme to http or https:</p> + + <pre class="prettyprint lang-config">RewriteEngine On + +RewriteCond "%{HTTPS}" =off +RewriteRule "." "-" [E=protocol:http] +RewriteCond "%{HTTPS}" =on +RewriteRule "." "-" [E=protocol:https] + +RewriteRule "^/mirror/foo/(.*)" "%{ENV:protocol}://backend.example.com/$1" [P] +ProxyPassReverse "/mirror/foo/" "http://backend.example.com/" +ProxyPassReverse "/mirror/foo/" "https://backend.example.com/"</pre> + + + <div class="note"><h3><a id="protoupgrade" name="protoupgrade">Protocol Upgrade</a></h3> + <p>Since Apache HTTP Server 2.4.47, protocol Upgrade (tunneling) can be handled + end-to-end by <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code> using the <code class="directive">ProxyPass</code> + parameter <var><a href="#upgrade">upgrade</a></var>.</p> + <p>End-to-end means that the HTTP Upgrade request from the client/browser is first + forwarded by <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code> to the origin server and the connection + will be upgraded (and tunneled by <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code>) only if the origin + server accepts/initiates the upgrade (HTTP response <code>101 Switching Protocols</code>). + If the origin server responds with anything else <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code> + will continue forwarding (and enforcing) the HTTP protocol as usual for this + connection.</p> + <p>See <a href="#wsupgrade">Websocket Upgrade (2.4.47 and later)</a> for an example of + configuration using <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code>.</p> + <p>For Apache HTTP Server 2.4.46 and earlier (or if + <code class="directive"><a href="../mod/mod_proxy_wstunnel.html#proxywebsocketfallbacktoproxyhttp">ProxyWebsocketFallbackToProxyHttp</a></code> + from 2.4.48 and later disables <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code> handling), see the + documentation of <code class="module"><a href="../mod/mod_proxy_wstunnel.html">mod_proxy_wstunnel</a></code> for how to proxy the WebSocket + protocol.</p> + </div> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyPassInherit" id="ProxyPassInherit">ProxyPassInherit</a> <a name="proxypassinherit" id="proxypassinherit">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Inherit ProxyPass directives defined from the main server</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassInherit On|Off</code></td></tr> +<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyPassInherit On</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>ProxyPassInherit is only available in Apache HTTP Server 2.4.5 and later. + </td></tr> +</table> + <p>This directive will cause the current server/vhost to "inherit" + <code class="directive"><a href="#proxypass">ProxyPass</a></code> + directives defined in the main server. This can cause issues and + inconsistent behavior if using the Balancer Manager for dynamic changes + and so should be disabled if using that feature.</p> + <p>The setting in the global server defines the default for all vhosts.</p> + <p>Disabling ProxyPassInherit also disables <code class="directive"><a href="#balancerinherit">BalancerInherit</a></code>.</p> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyPassInterpolateEnv" id="ProxyPassInterpolateEnv">ProxyPassInterpolateEnv</a> <a name="proxypassinterpolateenv" id="proxypassinterpolateenv">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enable Environment Variable interpolation in Reverse Proxy configurations</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassInterpolateEnv On|Off</code></td></tr> +<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyPassInterpolateEnv Off</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in httpd 2.2.9 and later</td></tr> +</table> + <p>This directive, together with the <code>interpolate</code> argument to + <code class="directive">ProxyPass</code>, <code class="directive">ProxyPassReverse</code>, + <code class="directive">ProxyPassReverseCookieDomain</code>, and + <code class="directive">ProxyPassReverseCookiePath</code>, + enables reverse proxies to be dynamically + configured using environment variables which may be set by + another module such as <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. + It affects the <code class="directive">ProxyPass</code>, + <code class="directive">ProxyPassReverse</code>, + <code class="directive">ProxyPassReverseCookieDomain</code>, and + <code class="directive">ProxyPassReverseCookiePath</code> directives + and causes them to substitute the value of an environment + variable <code>varname</code> for the string <code>${varname}</code> + in configuration directives if the <code>interpolate</code> option is set.</p> + <p>The scheme/hostname/port portion of <code class="directive">ProxyPass</code> may + contain variables, but only the ones available when the directive is parsed + (for example, using <code class="directive"><a href="../mod/core.html#define">Define</a></code>). + For all the other use cases, please consider using + <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> instead.</p> + <div class="warning"><h3>Performance warning</h3> + <p>Keep this turned off unless you need it! + Adding variables to <code class="directive">ProxyPass</code> for example may lead to + the use of the default mod_proxy's workers configured (that don't allow any fine + tuning like connections reuse, etc..).</p> + </div> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyPassMatch" id="ProxyPassMatch">ProxyPassMatch</a> <a name="proxypassmatch" id="proxypassmatch">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maps remote servers into the local server URL-space using regular expressions</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassMatch [<var>regex</var>] !|<var>url</var> [<var>key=value</var> + <var>[key=value</var> ...]]</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +</table> + <p>This directive is equivalent to <code class="directive"><a href="#proxypass">ProxyPass</a></code> + but makes use of regular expressions instead of simple prefix matching. The + supplied regular expression is matched against the <var>url</var>, and if it + matches, the server will substitute any parenthesized matches into the given + string and use it as a new <var>url</var>.</p> + + <div class="note"><strong>Note: </strong>This directive cannot be used within a + <code><Directory></code> context.</div> + + <p>Suppose the local server has address <code>http://example.com/</code>; + then</p> + + <pre class="prettyprint lang-config">ProxyPassMatch "^/(.*\.gif)$" "http://backend.example.com/$1"</pre> + + + <p>will cause a local request for + <code>http://example.com/foo/bar.gif</code> to be internally converted + into a proxy request to <code>http://backend.example.com/foo/bar.gif</code>.</p> + <div class="note"><h3>Note</h3> + <p>The URL argument must be parsable as a URL <em>before</em> regexp + substitutions (as well as after). This limits the matches you can use. + For instance, if we had used</p> + <pre class="prettyprint lang-config">ProxyPassMatch "^(/.*\.gif)$" "http://backend.example.com:8000$1"</pre> + + <p>in our previous example, it would fail with a syntax error + at server startup. This is a bug (PR 46665 in the ASF bugzilla), + and the workaround is to reformulate the match:</p> + <pre class="prettyprint lang-config">ProxyPassMatch "^/(.*\.gif)$" "http://backend.example.com:8000/$1"</pre> + + </div> + <p>The <code>!</code> directive is useful in situations where you don't want + to reverse-proxy a subdirectory.</p> + + <p>When used inside a <code class="directive"><a href="../mod/core.html#locationmatch"><LocationMatch></a></code> section, the first argument is omitted and the + regexp is obtained from the <code class="directive"><a href="../mod/core.html#locationmatch"><LocationMatch></a></code>.</p> + + <p>If you require a more flexible reverse-proxy configuration, see the + <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> directive with the + <code>[P]</code> flag.</p> + + <div class="note"> + <h3>Default Substitution</h3> + <p>When the URL parameter doesn't use any backreferences into the regular + expression, the original URL will be appended to the URL parameter. + </p> + </div> + + <div class="warning"> + <h3>Security Warning</h3> + <p>Take care when constructing the target URL of the rule, considering + the security impact from allowing the client influence over the set of + URLs to which your server will act as a proxy. Ensure that the scheme + and hostname part of the URL is either fixed or does not allow the + client undue influence.</p> + </div> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyPassReverse" id="ProxyPassReverse">ProxyPassReverse</a> <a name="proxypassreverse" id="proxypassreverse">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Adjusts the URL in HTTP response headers sent from a reverse +proxied server</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassReverse [<var>path</var>] <var>url</var> +[interpolate]</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +</table> + <p>This directive lets Apache httpd adjust the URL in the <code>Location</code>, + <code>Content-Location</code> and <code>URI</code> headers on HTTP + redirect responses. This is essential when Apache httpd is used as a + reverse proxy (or gateway) to avoid bypassing the reverse proxy + because of HTTP redirects on the backend servers which stay behind + the reverse proxy.</p> + + <p>Only the HTTP response headers specifically mentioned above + will be rewritten. Apache httpd will not rewrite other response + headers, nor will it by default rewrite URL references inside HTML pages. + This means that if the proxied content contains absolute URL + references, they will bypass the proxy. To rewrite HTML content to + match the proxy, you must load and enable <code class="module"><a href="../mod/mod_proxy_html.html">mod_proxy_html</a></code>. + </p> + + <p><var>path</var> is the name of a local virtual path; <var>url</var> is a + partial URL for the remote server. + These parameters are used the same way as for the + <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.</p> + + <p>For example, suppose the local server has address + <code>http://example.com/</code>; then</p> + + <pre class="prettyprint lang-config">ProxyPass "/mirror/foo/" "http://backend.example.com/" +ProxyPassReverse "/mirror/foo/" "http://backend.example.com/" +ProxyPassReverseCookieDomain "backend.example.com" "public.example.com" +ProxyPassReverseCookiePath "/" "/mirror/foo/"</pre> + + + <p>will not only cause a local request for the + <code>http://example.com/mirror/foo/bar</code> to be internally converted + into a proxy request to <code>http://backend.example.com/bar</code> + (the functionality which <code>ProxyPass</code> provides here). + It also takes care of redirects which the server <code>backend.example.com</code> + sends when redirecting <code>http://backend.example.com/bar</code> to + <code>http://backend.example.com/quux</code> . Apache httpd adjusts this to + <code>http://example.com/mirror/foo/quux</code> before forwarding the HTTP + redirect response to the client. Note that the hostname used for + constructing the URL is chosen in respect to the setting of the <code class="directive"><a href="../mod/core.html#usecanonicalname">UseCanonicalName</a></code> directive.</p> + + <p>Note that this <code class="directive">ProxyPassReverse</code> directive can + also be used in conjunction with the proxy feature + (<code>RewriteRule ... [P]</code>) from <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> + because it doesn't depend on a corresponding <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.</p> + + <p>The optional <code>interpolate</code> keyword, used together with + <code class="directive"><a href="#proxypassinterpolateenv">ProxyPassInterpolateEnv</a></code>, enables interpolation + of environment variables specified using the format <var>${VARNAME}</var>. + Note that interpolation is not supported within the scheme portion of a + URL.</p> + + <p>When used inside a <code class="directive"><a href="../mod/core.html#location"><Location></a></code> section, the first argument is omitted and the local + directory is obtained from the <code class="directive"><a href="../mod/core.html#location"><Location></a></code>. The same occurs inside a <code class="directive"><a href="../mod/core.html#locationmatch"><LocationMatch></a></code> section, but will probably not work as + intended, as ProxyPassReverse will interpret the regexp literally as a + path; if needed in this situation, specify the ProxyPassReverse outside + the section or in a separate <code class="directive"><a href="../mod/core.html#location"><Location></a></code> section.</p> + + <p>This directive is not supported in <code class="directive"><a href="../mod/core.html#directory"><Directory></a></code> or <code class="directive"><a href="../mod/core.html#files"><Files></a></code> sections.</p> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyPassReverseCookieDomain" id="ProxyPassReverseCookieDomain">ProxyPassReverseCookieDomain</a> <a name="proxypassreversecookiedomain" id="proxypassreversecookiedomain">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Adjusts the Domain string in Set-Cookie headers from a reverse- +proxied server</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassReverseCookieDomain <var>internal-domain</var> +<var>public-domain</var> [interpolate]</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +</table> +<p>Usage is basically similar to +<code class="directive"><a href="#proxypassreverse">ProxyPassReverse</a></code>, but instead of +rewriting headers that are a URL, this rewrites the <code>domain</code> +string in <code>Set-Cookie</code> headers.</p> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyPassReverseCookiePath" id="ProxyPassReverseCookiePath">ProxyPassReverseCookiePath</a> <a name="proxypassreversecookiepath" id="proxypassreversecookiepath">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Adjusts the Path string in Set-Cookie headers from a reverse- +proxied server</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassReverseCookiePath <var>internal-path</var> +<var>public-path</var> [interpolate]</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +</table> +<p> +Useful in conjunction with +<code class="directive"><a href="#proxypassreverse">ProxyPassReverse</a></code> +in situations where backend URL paths are mapped to public paths on the +reverse proxy. This directive rewrites the <code>path</code> string in +<code>Set-Cookie</code> headers. If the beginning of the cookie path matches +<var>internal-path</var>, the cookie path will be replaced with +<var>public-path</var>. +</p><p> +In the example given with +<code class="directive"><a href="#proxypassreverse">ProxyPassReverse</a></code>, the directive: +</p> + <pre class="prettyprint lang-config">ProxyPassReverseCookiePath "/" "/mirror/foo/"</pre> + +<p> +will rewrite a cookie with backend path <code>/</code> (or +<code>/example</code> or, in fact, anything) to <code>/mirror/foo/</code>. +</p> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyPreserveHost" id="ProxyPreserveHost">ProxyPreserveHost</a> <a name="proxypreservehost" id="proxypreservehost">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Use incoming Host HTTP request header for proxy +request</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPreserveHost On|Off</code></td></tr> +<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyPreserveHost Off</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Usable in directory +context in 2.3.3 and later.</td></tr> +</table> + <p>When enabled, this option will pass the <code>Host:</code> line from the incoming + request to the proxied host, instead of the hostname specified in the + <code class="directive"><a href="#proxypass">ProxyPass</a></code> line.</p> + + <p>This option should normally be turned <code>Off</code>. It is mostly + useful in special configurations like proxied mass name-based virtual + hosting, where the original Host header needs to be evaluated by the + backend server.</p> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyReceiveBufferSize" id="ProxyReceiveBufferSize">ProxyReceiveBufferSize</a> <a name="proxyreceivebuffersize" id="proxyreceivebuffersize">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Network buffer size for proxied HTTP and FTP +connections</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyReceiveBufferSize <var>bytes</var></code></td></tr> +<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyReceiveBufferSize 0</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +</table> + <p>The <code class="directive">ProxyReceiveBufferSize</code> directive specifies an + explicit (TCP/IP) network buffer size for proxied HTTP and FTP connections, + for increased throughput. It has to be greater than <code>512</code> or set + to <code>0</code> to indicate that the system's default buffer size should + be used.</p> + + <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">ProxyReceiveBufferSize 2048</pre> +</div> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyRemote" id="ProxyRemote">ProxyRemote</a> <a name="proxyremote" id="proxyremote">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Remote proxy used to handle certain requests</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyRemote <var>match</var> <var>remote-server</var></code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +</table> + <p>This defines remote proxies to this proxy. <var>match</var> is either the + name of a URL-scheme that the remote server supports, or a partial URL + for which the remote server should be used, or <code>*</code> to indicate + the server should be contacted for all requests. <var>remote-server</var> is + a partial URL for the remote server. Syntax:</p> + + <div class="example"><p><code> + <dfn>remote-server</dfn> = + <var>scheme</var>://<var>hostname</var>[:<var>port</var>] + </code></p></div> + + <p><var>scheme</var> is effectively the protocol that should be used to + communicate with the remote server; only <code>http</code> and <code>https</code> + are supported by this module. When using <code>https</code>, the requests + are forwarded through the remote proxy using the HTTP CONNECT method.</p> + + <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">ProxyRemote "http://goodguys.example.com/" "http://mirrorguys.example.com:8000" +ProxyRemote "*" "http://cleverproxy.localdomain" +ProxyRemote "ftp" "http://ftpproxy.mydomain:8080"</pre> +</div> + + <p>In the last example, the proxy will forward FTP requests, encapsulated + as yet another HTTP proxy request, to another proxy which can handle + them.</p> + + <p>This option also supports reverse proxy configuration; a backend + webserver can be embedded within a virtualhost URL space even if that + server is hidden by another forward proxy.</p> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyRemoteMatch" id="ProxyRemoteMatch">ProxyRemoteMatch</a> <a name="proxyremotematch" id="proxyremotematch">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Remote proxy used to handle requests matched by regular +expressions</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyRemoteMatch <var>regex</var> <var>remote-server</var></code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +</table> + <p>The <code class="directive">ProxyRemoteMatch</code> is identical to the + <code class="directive"><a href="#proxyremote">ProxyRemote</a></code> directive, except that + the first argument is a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a> + match against the requested URL.</p> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyRequests" id="ProxyRequests">ProxyRequests</a> <a name="proxyrequests" id="proxyrequests">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables forward (standard) proxy requests</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyRequests On|Off</code></td></tr> +<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyRequests Off</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +</table> + <p>This allows or prevents Apache httpd from functioning as a forward proxy + server. (Setting ProxyRequests to <code>Off</code> does not disable use of + the <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.)</p> + + <p>In a typical reverse proxy or gateway configuration, this + option should be set to + <code>Off</code>.</p> + + <p>In order to get the functionality of proxying HTTP or FTP sites, you + need also <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code> or <code class="module"><a href="../mod/mod_proxy_ftp.html">mod_proxy_ftp</a></code> + (or both) present in the server.</p> + + <p>In order to get the functionality of (forward) proxying HTTPS sites, you + need <code class="module"><a href="../mod/mod_proxy_connect.html">mod_proxy_connect</a></code> enabled in the server.</p> + + <div class="warning"><h3>Warning</h3> + <p>Do not enable proxying with <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> until you have <a href="#access">secured your server</a>. Open proxy servers are dangerous + both to your network and to the Internet at large.</p> + </div> + +<h3>See also</h3> +<ul> +<li><a href="#forwardreverse">Forward and Reverse Proxies/Gateways</a></li> +</ul> +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxySet" id="ProxySet">ProxySet</a> <a name="proxyset" id="proxyset">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Set various Proxy balancer or member parameters</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxySet <var>url</var> <var>key=value [key=value ...]</var></code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>ProxySet is only available in Apache HTTP Server 2.2 + and later.</td></tr> +</table> + <p>This directive is used as an alternate method of setting any of the + parameters available to Proxy balancers and workers normally done via the + <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive. If used + within a <code><Proxy <var>balancer url|worker url</var>></code> + container directive, the <var>url</var> argument is not required. As a side + effect the respective balancer or worker gets created. This can be useful + when doing reverse proxying via a + <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> instead of a + <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.</p> + + <div class="example"><pre class="prettyprint lang-config"><Proxy "balancer://hotcluster"> + BalancerMember "http://www2.example.com:8080" loadfactor=1 + BalancerMember "http://www3.example.com:8080" loadfactor=2 + ProxySet lbmethod=bytraffic +</Proxy></pre> +</div> + + <pre class="prettyprint lang-config"><Proxy "http://backend"> + ProxySet keepalive=On +</Proxy></pre> + + + <pre class="prettyprint lang-config">ProxySet "balancer://foo" lbmethod=bytraffic timeout=15</pre> + + + <pre class="prettyprint lang-config">ProxySet "ajp://backend:7001" timeout=15</pre> + + + <div class="warning"><h3>Warning</h3> + <p>Keep in mind that the same parameter key can have a different meaning + depending whether it is applied to a balancer or a worker, as shown by + the two examples above regarding timeout.</p> + </div> + + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxySourceAddress" id="ProxySourceAddress">ProxySourceAddress</a> <a name="proxysourceaddress" id="proxysourceaddress">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Set local IP address for outgoing proxy connections</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxySourceAddress <var>address</var></code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in version 2.3.9 and later</td></tr> +</table> + <p>This directive allows to set a specific local address to bind to when connecting + to a backend server.</p> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyStatus" id="ProxyStatus">ProxyStatus</a> <a name="proxystatus" id="proxystatus">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Show Proxy LoadBalancer status in mod_status</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyStatus Off|On|Full</code></td></tr> +<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyStatus Off</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in version 2.2 and later</td></tr> +</table> + <p>This directive determines whether or not proxy + loadbalancer status data is displayed via the <code class="module"><a href="../mod/mod_status.html">mod_status</a></code> + server-status page.</p> + <div class="note"><h3>Note</h3> + <p><strong>Full</strong> is synonymous with <strong>On</strong></p> + </div> + + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyTimeout" id="ProxyTimeout">ProxyTimeout</a> <a name="proxytimeout" id="proxytimeout">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Network timeout for proxied requests</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyTimeout <var>seconds</var></code></td></tr> +<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Value of <code class="directive"><a href="../mod/core.html#timeout">Timeout</a></code></code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +</table> + <p>This directive allows a user to specify a timeout on proxy requests. + This is useful when you have a slow/buggy appserver which hangs, and you + would rather just return a timeout and fail gracefully instead of waiting + however long it takes the server to return.</p> + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ProxyVia" id="ProxyVia">ProxyVia</a> <a name="proxyvia" id="proxyvia">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Information provided in the <code>Via</code> HTTP response +header for proxied requests</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyVia On|Off|Full|Block</code></td></tr> +<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyVia Off</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr> +</table> + <p>This directive controls the use of the <code>Via:</code> HTTP + header by the proxy. Its intended use is to control the flow of + proxy requests along a chain of proxy servers. See <a href="http://www.ietf.org/rfc/rfc2616.txt">RFC 2616</a> (HTTP/1.1), section + 14.45 for an explanation of <code>Via:</code> header lines.</p> + + <ul> + <li>If set to <code>Off</code>, which is the default, no special processing + is performed. If a request or reply contains a <code>Via:</code> header, + it is passed through unchanged.</li> + + <li>If set to <code>On</code>, each request and reply will get a + <code>Via:</code> header line added for the current host.</li> + + <li>If set to <code>Full</code>, each generated <code>Via:</code> header + line will additionally have the Apache httpd server version shown as a + <code>Via:</code> comment field.</li> + + <li>If set to <code>Block</code>, every proxy request will have all its + <code>Via:</code> header lines removed. No new <code>Via:</code> header will + be generated.</li> + </ul> + +</div> +</div> +<div class="bottomlang"> +<p><span>Available Languages: </span><a href="../en/mod/mod_proxy.html" title="English"> en </a> | +<a href="../fr/mod/mod_proxy.html" hreflang="fr" rel="alternate" title="Français"> fr </a> | +<a href="../ja/mod/mod_proxy.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a></p> +</div><div class="top"><a href="#page-header"><img src="../images/up.gif" alt="top" /></a></div><div class="section"><h2><a id="comments_section" name="comments_section">Comments</a></h2><div class="warning"><strong>Notice:</strong><br />This is not a Q&A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Libera.chat, or sent to our <a href="https://httpd.apache.org/lists.html">mailing lists</a>.</div> +<script type="text/javascript"><!--//--><![CDATA[//><!-- +var comments_shortname = 'httpd'; +var comments_identifier = 'http://httpd.apache.org/docs/2.4/mod/mod_proxy.html'; +(function(w, d) { + if (w.location.hostname.toLowerCase() == "httpd.apache.org") { + d.write('<div id="comments_thread"><\/div>'); + var s = d.createElement('script'); + s.type = 'text/javascript'; + s.async = true; + s.src = 'https://comments.apache.org/show_comments.lua?site=' + comments_shortname + '&page=' + comments_identifier; + (d.getElementsByTagName('head')[0] || d.getElementsByTagName('body')[0]).appendChild(s); + } + else { + d.write('<div id="comments_thread">Comments are disabled for this page at the moment.<\/div>'); + } +})(window, document); +//--><!]]></script></div><div id="footer"> +<p class="apache">Copyright 2023 The Apache Software Foundation.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p> +<p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p></div><script type="text/javascript"><!--//--><![CDATA[//><!-- +if (typeof(prettyPrint) !== 'undefined') { + prettyPrint(); +} +//--><!]]></script> +</body></html>
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