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16 <p class="apache">Apache HTTP Server Version 2.3</p>
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21 <div id="page-content">
22 <div id="preamble"><h1>Apache Module mod_proxy</h1>
24 <p><span>Available Languages: </span><a href="../en/mod/mod_proxy.html" title="English"> en </a> |
25 <a href="../ja/mod/mod_proxy.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a></p>
27 <table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>HTTP/1.1 proxy/gateway server</td></tr>
28 <tr><th><a href="module-dict.html#Status">Status:</a></th><td>Extension</td></tr>
29 <tr><th><a href="module-dict.html#ModuleIdentifier">Module Identifier:</a></th><td>proxy_module</td></tr>
30 <tr><th><a href="module-dict.html#SourceFile">Source File:</a></th><td>mod_proxy.c</td></tr></table>
33 <div class="warning"><h3>Warning</h3>
34 <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
35 network and to the Internet at large.</p>
38 <p>This module implements a proxy/gateway for Apache. It implements
39 proxying capability for <code>AJP13</code> (Apache JServe Protocol
40 version 1.3), <code>FTP</code>, <code>CONNECT</code> (for SSL),
41 <code>HTTP/0.9</code>, <code>HTTP/1.0</code>, and <code>HTTP/1.1</code>.
42 The module can be configured to connect to other proxy modules for these
43 and other protocols.</p>
45 <p>Apache's proxy features are divided into several modules in
46 addition to <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>:
47 <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code>, <code class="module"><a href="../mod/mod_proxy_ftp.html">mod_proxy_ftp</a></code>,
48 <code class="module"><a href="../mod/mod_proxy_ajp.html">mod_proxy_ajp</a></code>, <code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code>,
49 and <code class="module"><a href="../mod/mod_proxy_connect.html">mod_proxy_connect</a></code>. Thus, if you want to use
50 one or more of the particular proxy functions, load
51 <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> <em>and</em> the appropriate module(s)
52 into the server (either statically at compile-time or dynamically
53 via the <code class="directive"><a href="../mod/mod_so.html#loadmodule">LoadModule</a></code>
56 <p>In addition, extended features are provided by other modules.
57 Caching is provided by <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code> and related
58 modules. The ability to contact remote servers using the SSL/TLS
59 protocol is provided by the <code>SSLProxy*</code> directives of
60 <code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code>. These additional modules will need
61 to be loaded and configured to take advantage of these features.</p>
63 <div id="quickview"><h3 class="directives">Directives</h3>
65 <li><img alt="" src="../images/down.gif" /> <a href="#allowconnect">AllowCONNECT</a></li>
66 <li><img alt="" src="../images/down.gif" /> <a href="#balancermember">BalancerMember</a></li>
67 <li><img alt="" src="../images/down.gif" /> <a href="#noproxy">NoProxy</a></li>
68 <li><img alt="" src="../images/down.gif" /> <a href="#proxy"><Proxy></a></li>
69 <li><img alt="" src="../images/down.gif" /> <a href="#proxybadheader">ProxyBadHeader</a></li>
70 <li><img alt="" src="../images/down.gif" /> <a href="#proxyblock">ProxyBlock</a></li>
71 <li><img alt="" src="../images/down.gif" /> <a href="#proxydomain">ProxyDomain</a></li>
72 <li><img alt="" src="../images/down.gif" /> <a href="#proxyerroroverride">ProxyErrorOverride</a></li>
73 <li><img alt="" src="../images/down.gif" /> <a href="#proxyiobuffersize">ProxyIOBufferSize</a></li>
74 <li><img alt="" src="../images/down.gif" /> <a href="#proxymatch"><ProxyMatch></a></li>
75 <li><img alt="" src="../images/down.gif" /> <a href="#proxymaxforwards">ProxyMaxForwards</a></li>
76 <li><img alt="" src="../images/down.gif" /> <a href="#proxypass">ProxyPass</a></li>
77 <li><img alt="" src="../images/down.gif" /> <a href="#proxypassinterpolateenv">ProxyPassInterpolateEnv</a></li>
78 <li><img alt="" src="../images/down.gif" /> <a href="#proxypassreverse">ProxyPassReverse</a></li>
79 <li><img alt="" src="../images/down.gif" /> <a href="#proxypassreversecookiedomain">ProxyPassReverseCookieDomain</a></li>
80 <li><img alt="" src="../images/down.gif" /> <a href="#proxypassreversecookiepath">ProxyPassReverseCookiePath</a></li>
81 <li><img alt="" src="../images/down.gif" /> <a href="#proxypreservehost">ProxyPreserveHost</a></li>
82 <li><img alt="" src="../images/down.gif" /> <a href="#proxyreceivebuffersize">ProxyReceiveBufferSize</a></li>
83 <li><img alt="" src="../images/down.gif" /> <a href="#proxyremote">ProxyRemote</a></li>
84 <li><img alt="" src="../images/down.gif" /> <a href="#proxyremotematch">ProxyRemoteMatch</a></li>
85 <li><img alt="" src="../images/down.gif" /> <a href="#proxyrequests">ProxyRequests</a></li>
86 <li><img alt="" src="../images/down.gif" /> <a href="#proxytimeout">ProxyTimeout</a></li>
87 <li><img alt="" src="../images/down.gif" /> <a href="#proxyvia">ProxyVia</a></li>
91 <li><img alt="" src="../images/down.gif" /> <a href="#forwardreverse">Forward and Reverse Proxies</a></li>
92 <li><img alt="" src="../images/down.gif" /> <a href="#examples">Basic Examples</a></li>
93 <li><img alt="" src="../images/down.gif" /> <a href="#access">Controlling access to your proxy</a></li>
94 <li><img alt="" src="../images/down.gif" /> <a href="#startup">Slow Startup</a></li>
95 <li><img alt="" src="../images/down.gif" /> <a href="#intranet">Intranet Proxy</a></li>
96 <li><img alt="" src="../images/down.gif" /> <a href="#envsettings">Protocol Adjustments</a></li>
97 <li><img alt="" src="../images/down.gif" /> <a href="#request-bodies">Request Bodys</a></li>
98 </ul><h3>See also</h3>
100 <li><code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code></li>
101 <li><code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code></li>
102 <li><code class="module"><a href="../mod/mod_proxy_ftp.html">mod_proxy_ftp</a></code></li>
103 <li><code class="module"><a href="../mod/mod_proxy_connect.html">mod_proxy_connect</a></code></li>
104 <li><code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code></li>
105 <li><code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code></li>
107 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
108 <div class="section">
109 <h2><a name="forwardreverse" id="forwardreverse">Forward and Reverse Proxies</a></h2>
110 <p>Apache can be configured in both a <dfn>forward</dfn> and
111 <dfn>reverse</dfn> proxy mode.</p>
113 <p>An ordinary <dfn>forward proxy</dfn> is an intermediate
114 server that sits between the client and the <em>origin
115 server</em>. In order to get content from the origin server,
116 the client sends a request to the proxy naming the origin server
117 as the target and the proxy then requests the content from the
118 origin server and returns it to the client. The client must be
119 specially configured to use the forward proxy to access other
122 <p>A typical usage of a forward proxy is to provide Internet
123 access to internal clients that are otherwise restricted by a
124 firewall. The forward proxy can also use caching (as provided
125 by <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code>) to reduce network usage.</p>
127 <p>The forward proxy is activated using the <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> directive. Because
128 forward proxys allow clients to access arbitrary sites through
129 your server and to hide their true origin, it is essential that
130 you <a href="#access">secure your server</a> so that only
131 authorized clients can access the proxy before activating a
134 <p>A <dfn>reverse proxy</dfn>, by contrast, appears to the
135 client just like an ordinary web server. No special
136 configuration on the client is necessary. The client makes
137 ordinary requests for content in the name-space of the reverse
138 proxy. The reverse proxy then decides where to send those
139 requests, and returns the content as if it was itself the
142 <p>A typical usage of a reverse proxy is to provide Internet
143 users access to a server that is behind a firewall. Reverse
144 proxies can also be used to balance load among several back-end
145 servers, or to provide caching for a slower back-end server.
146 In addition, reverse proxies can be used simply to bring
147 several servers into the same URL space.</p>
149 <p>A reverse proxy is activated using the <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive or the
150 <code>[P]</code> flag to the <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> directive. It is
151 <strong>not</strong> necessary to turn <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> on in order to
152 configure a reverse proxy.</p>
153 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
154 <div class="section">
155 <h2><a name="examples" id="examples">Basic Examples</a></h2>
157 <p>The examples below are only a very basic idea to help you
158 get started. Please read the documentation on the individual
161 <p>In addition, if you wish to have caching enabled, consult
162 the documentation from <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code>.</p>
164 <div class="example"><h3>Forward Proxy</h3><p><code>
165 ProxyRequests On<br />
168 <Proxy *><br />
169 <span class="indent">
170 Order deny,allow<br />
172 Allow from internal.example.com<br />
177 <div class="example"><h3>Reverse Proxy</h3><p><code>
178 ProxyRequests Off<br />
180 <Proxy *><br />
181 <span class="indent">
182 Order deny,allow<br />
187 ProxyPass /foo http://foo.example.com/bar<br />
188 ProxyPassReverse /foo http://foo.example.com/bar
190 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
191 <div class="section">
192 <h2><a name="access" id="access">Controlling access to your proxy</a></h2>
193 <p>You can control who can access your proxy via the <code class="directive"><a href="#proxy"><Proxy></a></code> control block as in
194 the following example:</p>
196 <div class="example"><p><code>
197 <Proxy *><br />
198 <span class="indent">
199 Order Deny,Allow<br />
201 Allow from 192.168.0<br />
206 <p>For more information on access control directives, see
207 <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code>.</p>
209 <p>Strictly limiting access is essential if you are using a
210 forward proxy (using the <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> directive).
211 Otherwise, your server can be used by any client to access
212 arbitrary hosts while hiding his or her true identity. This is
213 dangerous both for your network and for the Internet at large.
214 When using a reverse proxy (using the <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive with
215 <code>ProxyRequests Off</code>), access control is less
216 critical because clients can only contact the hosts that you
217 have specifically configured.</p>
219 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
220 <div class="section">
221 <h2><a name="startup" id="startup">Slow Startup</a></h2>
222 <p>If you're using the <code class="directive"><a href="#proxyblock">ProxyBlock</a></code> directive, hostnames' IP addresses are looked up
223 and cached during startup for later match test. This may take a few
224 seconds (or more) depending on the speed with which the hostname lookups
226 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
227 <div class="section">
228 <h2><a name="intranet" id="intranet">Intranet Proxy</a></h2>
229 <p>An Apache proxy server situated in an intranet needs to forward
230 external requests through the company's firewall (for this, configure
231 the <code class="directive"><a href="#proxyremote">ProxyRemote</a></code> directive
232 to forward the respective <var>scheme</var> to the firewall proxy).
233 However, when it has to
234 access resources within the intranet, it can bypass the firewall when
235 accessing hosts. The <code class="directive"><a href="#noproxy">NoProxy</a></code>
236 directive is useful for specifying which hosts belong to the intranet and
237 should be accessed directly.</p>
239 <p>Users within an intranet tend to omit the local domain name from their
240 WWW requests, thus requesting "http://somehost/" instead of
241 <code>http://somehost.example.com/</code>. Some commercial proxy servers
242 let them get away with this and simply serve the request, implying a
243 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 can return
244 a redirect response and send the client to the correct, fully qualified,
245 server address. This is the preferred method since the user's bookmark
246 files will then contain fully qualified hosts.</p>
247 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
248 <div class="section">
249 <h2><a name="envsettings" id="envsettings">Protocol Adjustments</a></h2>
250 <p>For circumstances where <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> is sending
251 requests to an origin server that doesn't properly implement
252 keepalives or HTTP/1.1, there are two <a href="../env.html">environment variables</a> that can force the
253 request to use HTTP/1.0 with no keepalive. These are set via the
254 <code class="directive"><a href="../mod/mod_env.html#setenv">SetEnv</a></code> directive.</p>
256 <p>These are the <code>force-proxy-request-1.0</code> and
257 <code>proxy-nokeepalive</code> notes.</p>
259 <div class="example"><p><code>
260 <Location /buggyappserver/><br />
261 <span class="indent">
262 ProxyPass http://buggyappserver:7001/foo/<br />
263 SetEnv force-proxy-request-1.0 1<br />
264 SetEnv proxy-nokeepalive 1<br />
269 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
270 <div class="section">
271 <h2><a name="request-bodies" id="request-bodies">Request Bodys</a></h2>
273 <p>Some request methods such as POST include a request body.
274 The HTTP protocol requires that requests which include a body
275 either use chunked transfer encoding or send a
276 <code>Content-Length</code> request header. When passing these
277 requests on to the origin server, <code class="module"><a href="../mod/mod_proxy_http.html">mod_proxy_http</a></code>
278 will always attempt to send the <code>Content-Length</code>. But
279 if the body is large and the original request used chunked
280 encoding, then chunked encoding may also be used in the upstream
281 request. You can control this selection using <a href="../env.html">environment variables</a>. Setting
282 <code>proxy-sendcl</code> ensures maximum compatibility with
283 upstream servers by always sending the
284 <code>Content-Length</code>, while setting
285 <code>proxy-sendchunked</code> minimizes resource usage by using
286 chunked encoding.</p>
289 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
290 <div class="directive-section"><h2><a name="AllowCONNECT" id="AllowCONNECT">AllowCONNECT</a> <a name="allowconnect" id="allowconnect">Directive</a></h2>
291 <table class="directive">
292 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Ports that are allowed to <code>CONNECT</code> through the
294 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowCONNECT <var>port</var> [<var>port</var>] ...</code></td></tr>
295 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowCONNECT 443 563</code></td></tr>
296 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
297 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
298 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
300 <p>The <code class="directive">AllowCONNECT</code> directive specifies a list
301 of port numbers to which the proxy <code>CONNECT</code> method may
302 connect. Today's browsers use this method when a <code>https</code>
303 connection is requested and proxy tunneling over HTTP is in effect.</p>
305 <p>By default, only the default https port (<code>443</code>) and the
306 default snews port (<code>563</code>) are enabled. Use the
307 <code class="directive">AllowCONNECT</code> directive to override this default and
308 allow connections to the listed ports only.</p>
310 <p>Note that you'll need to have <code class="module"><a href="../mod/mod_proxy_connect.html">mod_proxy_connect</a></code> present
311 in the server in order to get the support for the <code>CONNECT</code> at
315 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
316 <div class="directive-section"><h2><a name="BalancerMember" id="BalancerMember">BalancerMember</a> <a name="balancermember" id="balancermember">Directive</a></h2>
317 <table class="directive">
318 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Add a member to a load balancing group</td></tr>
319 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>BalancerMember <var>url</var> [<var>key=value [key=value ...]]</var></code></td></tr>
320 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
321 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
322 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
323 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>BalancerMember is only available in Apache 2.2.0
326 <p>This directive adds a member to a load balancing group. It must be used
327 within a <code><Proxy <var>balancer://</var>...></code> container
328 directive, and can take any of the parameters available to
329 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directives.</p>
330 <p>One additional parameter is available only to <code class="directive"><a href="#balancermember">BalancerMember</a></code> directives:
331 <var>loadfactor</var>. This is the member load factor - a number between 1
332 (default) and 100, which defines the weighted load to be applied to the
333 member in question.</p>
336 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
337 <div class="directive-section"><h2><a name="NoProxy" id="NoProxy">NoProxy</a> <a name="noproxy" id="noproxy">Directive</a></h2>
338 <table class="directive">
339 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Hosts, domains, or networks that will be connected to
341 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>NoProxy <var>host</var> [<var>host</var>] ...</code></td></tr>
342 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
343 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
344 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
346 <p>This directive is only useful for Apache proxy servers within
347 intranets. The <code class="directive">NoProxy</code> directive specifies a
348 list of subnets, IP addresses, hosts and/or domains, separated by
349 spaces. A request to a host which matches one or more of these is
350 always served directly, without forwarding to the configured
351 <code class="directive"><a href="#proxyremote">ProxyRemote</a></code> proxy server(s).</p>
353 <div class="example"><h3>Example</h3><p><code>
354 ProxyRemote * http://firewall.mycompany.com:81<br />
355 NoProxy .mycompany.com 192.168.112.0/21
358 <p>The <var>host</var> arguments to the <code class="directive">NoProxy</code>
359 directive are one of the following type list:</p>
363 <dt><var><a name="domain" id="domain">Domain</a></var></dt>
365 <p>A <dfn>Domain</dfn> is a partially qualified DNS domain name, preceded
366 by a period. It represents a list of hosts which logically belong to the
367 same DNS domain or zone (<em>i.e.</em>, the suffixes of the hostnames are
368 all ending in <var>Domain</var>).</p>
370 <div class="example"><h3>Examples</h3><p><code>
374 <p>To distinguish <var>Domain</var>s from <var><a href="#hostname">Hostname</a></var>s (both syntactically and semantically; a DNS domain can
375 have a DNS A record, too!), <var>Domain</var>s are always written with a
378 <div class="note"><h3>Note</h3>
379 <p>Domain name comparisons are done without regard to the case, and
380 <var>Domain</var>s are always assumed to be anchored in the root of the
381 DNS tree, therefore two domains <code>.MyDomain.com</code> and
382 <code>.mydomain.com.</code> (note the trailing period) are considered
383 equal. Since a domain comparison does not involve a DNS lookup, it is much
384 more efficient than subnet comparison.</p>
388 <dt><var><a name="subnet" id="subnet">SubNet</a></var></dt>
390 <p>A <dfn>SubNet</dfn> is a partially qualified internet address in
391 numeric (dotted quad) form, optionally followed by a slash and the netmask,
392 specified as the number of significant bits in the <var>SubNet</var>. It is
393 used to represent a subnet of hosts which can be reached over a common
394 network interface. In the absence of the explicit net mask it is assumed
395 that omitted (or zero valued) trailing digits specify the mask. (In this
396 case, the netmask can only be multiples of 8 bits wide.) Examples:</p>
399 <dt><code>192.168</code> or <code>192.168.0.0</code></dt>
400 <dd>the subnet 192.168.0.0 with an implied netmask of 16 valid bits
401 (sometimes used in the netmask form <code>255.255.0.0</code>)</dd>
402 <dt><code>192.168.112.0/21</code></dt>
403 <dd>the subnet <code>192.168.112.0/21</code> with a netmask of 21
404 valid bits (also used in the form <code>255.255.248.0</code>)</dd>
407 <p>As a degenerate case, a <em>SubNet</em> with 32 valid bits is the
408 equivalent to an <var><a href="#ipadr">IPAddr</a></var>, while a <var>SubNet</var> with zero
409 valid bits (<em>e.g.</em>, 0.0.0.0/0) is the same as the constant
410 <var>_Default_</var>, matching any IP address.</p></dd>
413 <dt><var><a name="ipaddr" id="ipaddr">IPAddr</a></var></dt>
415 <p>A <dfn>IPAddr</dfn> represents a fully qualified internet address in
416 numeric (dotted quad) form. Usually, this address represents a host, but
417 there need not necessarily be a DNS domain name connected with the
419 <div class="example"><h3>Example</h3><p><code>
423 <div class="note"><h3>Note</h3>
424 <p>An <var>IPAddr</var> does not need to be resolved by the DNS system, so
425 it can result in more effective apache performance.</p>
429 <dt><var><a name="hostname" id="hostname">Hostname</a></var></dt>
431 <p>A <dfn>Hostname</dfn> is a fully qualified DNS domain name which can
432 be resolved to one or more <var><a href="#ipaddr">IPAddrs</a></var> via the
433 DNS domain name service. It represents a logical host (in contrast to
434 <var><a href="#domain">Domain</a></var>s, see above) and must be resolvable
435 to at least one <var><a href="#ipaddr">IPAddr</a></var> (or often to a list
436 of hosts with different <var><a href="#ipaddr">IPAddr</a></var>s).</p>
438 <div class="example"><h3>Examples</h3><p><code>
439 prep.ai.mit.edu<br />
443 <div class="note"><h3>Note</h3>
444 <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
445 DNS lookup can be avoided. Name resolution in Apache can take a remarkable
446 deal of time when the connection to the name server uses a slow PPP
448 <p><var>Hostname</var> comparisons are done without regard to the case,
449 and <var>Hostname</var>s are always assumed to be anchored in the root
450 of the DNS tree, therefore two hosts <code>WWW.MyDomain.com</code>
451 and <code>www.mydomain.com.</code> (note the trailing period) are
452 considered equal.</p>
458 <li><a href="../dns-caveats.html">DNS Issues</a></li>
461 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
462 <div class="directive-section"><h2><a name="Proxy" id="Proxy"><Proxy></a> <a name="proxy" id="proxy">Directive</a></h2>
463 <table class="directive">
464 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Container for directives applied to proxied resources</td></tr>
465 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><Proxy <var>wildcard-url</var>> ...</Proxy></code></td></tr>
466 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
467 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
468 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
470 <p>Directives placed in <code class="directive"><Proxy></code>
471 sections apply only to matching proxied content. Shell-style wildcards are
474 <p>For example, the following will allow only hosts in
475 <code>yournetwork.example.com</code> to access content via your proxy
478 <div class="example"><p><code>
479 <Proxy *><br />
480 <span class="indent">
481 Order Deny,Allow<br />
483 Allow from yournetwork.example.com<br />
488 <p>The following example will process all files in the <code>foo</code>
489 directory of <code>example.com</code> through the <code>INCLUDES</code>
490 filter when they are sent through the proxy server:</p>
492 <div class="example"><p><code>
493 <Proxy http://example.com/foo/*><br />
494 <span class="indent">
495 SetOutputFilter INCLUDES<br />
502 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
503 <div class="directive-section"><h2><a name="ProxyBadHeader" id="ProxyBadHeader">ProxyBadHeader</a> <a name="proxybadheader" id="proxybadheader">Directive</a></h2>
504 <table class="directive">
505 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determines how to handle bad header lines in a
507 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyBadHeader IsError|Ignore|StartBody</code></td></tr>
508 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyBadHeader IsError</code></td></tr>
509 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
510 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
511 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
512 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>available in Apache 2.0.44 and later</td></tr>
514 <p>The <code class="directive">ProxyBadHeader</code> directive determines the
515 behaviour of <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> if it receives syntactically invalid
516 header lines (<em>i.e.</em> containing no colon). The following arguments
520 <dt><code>IsError</code></dt>
521 <dd>Abort the request and end up with a 502 (Bad Gateway) response. This is
522 the default behaviour.</dd>
524 <dt><code>Ignore</code></dt>
525 <dd>Treat bad header lines as if they weren't sent.</dd>
527 <dt><code>StartBody</code></dt>
528 <dd>When receiving the first bad header line, finish reading the headers and
529 treat the remainder as body. This helps to work around buggy backend servers
530 which forget to insert an empty line between the headers and the body.</dd>
534 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
535 <div class="directive-section"><h2><a name="ProxyBlock" id="ProxyBlock">ProxyBlock</a> <a name="proxyblock" id="proxyblock">Directive</a></h2>
536 <table class="directive">
537 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Words, hosts, or domains that are banned from being
539 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyBlock *|<var>word</var>|<var>host</var>|<var>domain</var>
540 [<var>word</var>|<var>host</var>|<var>domain</var>] ...</code></td></tr>
541 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
542 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
543 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
545 <p>The <code class="directive">ProxyBlock</code> directive specifies a list of
546 words, hosts and/or domains, separated by spaces. HTTP, HTTPS, and
547 FTP document requests to sites whose names contain matched words,
548 hosts or domains are <em>blocked</em> by the proxy server. The proxy
549 module will also attempt to determine IP addresses of list items which
550 may be hostnames during startup, and cache them for match test as
551 well. That may slow down the startup time of the server.</p>
553 <div class="example"><h3>Example</h3><p><code>
554 ProxyBlock joes-garage.com some-host.co.uk rocky.wotsamattau.edu
557 <p><code>rocky.wotsamattau.edu</code> would also be matched if referenced by
560 <p>Note that <code>wotsamattau</code> would also be sufficient to match
561 <code>wotsamattau.edu</code>.</p>
563 <p>Note also that</p>
565 <div class="example"><p><code>
569 <p>blocks connections to all sites.</p>
572 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
573 <div class="directive-section"><h2><a name="ProxyDomain" id="ProxyDomain">ProxyDomain</a> <a name="proxydomain" id="proxydomain">Directive</a></h2>
574 <table class="directive">
575 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Default domain name for proxied requests</td></tr>
576 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyDomain <var>Domain</var></code></td></tr>
577 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
578 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
579 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
581 <p>This directive is only useful for Apache proxy servers within
582 intranets. The <code class="directive">ProxyDomain</code> directive specifies
583 the default domain which the apache proxy server will belong to. If a
584 request to a host without a domain name is encountered, a redirection
585 response to the same host with the configured <var>Domain</var> appended
586 will be generated.</p>
588 <div class="example"><h3>Example</h3><p><code>
589 ProxyRemote * http://firewall.mycompany.com:81<br />
590 NoProxy .mycompany.com 192.168.112.0/21<br />
591 ProxyDomain .mycompany.com
595 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
596 <div class="directive-section"><h2><a name="ProxyErrorOverride" id="ProxyErrorOverride">ProxyErrorOverride</a> <a name="proxyerroroverride" id="proxyerroroverride">Directive</a></h2>
597 <table class="directive">
598 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Override error pages for proxied content</td></tr>
599 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyErrorOverride On|Off</code></td></tr>
600 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyErrorOverride Off</code></td></tr>
601 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
602 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
603 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
604 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in version 2.0 and later</td></tr>
606 <p>This directive is useful for reverse-proxy setups, where you want to
607 have a common look and feel on the error pages seen by the end user.
608 This also allows for included files (via
609 <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>'s SSI) to get
610 the error code and act accordingly (default behavior would display
611 the error page of the proxied server, turning this on shows the SSI
614 <p>This directive does not affect the processing of informational (1xx),
615 normal success (2xx), or redirect (3xx) responses.</p>
618 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
619 <div class="directive-section"><h2><a name="ProxyIOBufferSize" id="ProxyIOBufferSize">ProxyIOBufferSize</a> <a name="proxyiobuffersize" id="proxyiobuffersize">Directive</a></h2>
620 <table class="directive">
621 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Determine size of internal data throughput buffer</td></tr>
622 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyIOBufferSize <var>bytes</var></code></td></tr>
623 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyIOBufferSize 8192</code></td></tr>
624 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
625 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
626 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
628 <p>The <code class="directive">ProxyIOBufferSize</code> directive adjusts the size
629 of the internal buffer, which is used as a scratchpad for the data between
630 input and output. The size must be less or equal <code>8192</code>.</p>
632 <p>In almost every case there's no reason to change that value.</p>
635 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
636 <div class="directive-section"><h2><a name="ProxyMatch" id="ProxyMatch"><ProxyMatch></a> <a name="proxymatch" id="proxymatch">Directive</a></h2>
637 <table class="directive">
638 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Container for directives applied to regular-expression-matched
639 proxied resources</td></tr>
640 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code><ProxyMatch <var>regex</var>> ...</ProxyMatch></code></td></tr>
641 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
642 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
643 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
645 <p>The <code class="directive"><ProxyMatch></code> directive is
646 identical to the <code class="directive"><a href="#proxy"><Proxy></a></code> directive, except it matches URLs
647 using <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expressions</a>.</p>
650 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
651 <div class="directive-section"><h2><a name="ProxyMaxForwards" id="ProxyMaxForwards">ProxyMaxForwards</a> <a name="proxymaxforwards" id="proxymaxforwards">Directive</a></h2>
652 <table class="directive">
653 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximium number of proxies that a request can be forwarded
655 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyMaxForwards <var>number</var></code></td></tr>
656 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyMaxForwards 10</code></td></tr>
657 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
658 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
659 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
660 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.0 and later</td></tr>
662 <p>The <code class="directive">ProxyMaxForwards</code> directive specifies the
663 maximum number of proxies through which a request may pass, if there's no
664 <code>Max-Forwards</code> header supplied with the request. This is
665 set to prevent infinite proxy loops, or a DoS attack.</p>
667 <div class="example"><h3>Example</h3><p><code>
672 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
673 <div class="directive-section"><h2><a name="ProxyPass" id="ProxyPass">ProxyPass</a> <a name="proxypass" id="proxypass">Directive</a></h2>
674 <table class="directive">
675 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maps remote servers into the local server URL-space</td></tr>
676 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPass [<var>path</var>] !|<var>url</var> [<var>key=value</var>
677 <var>[key=value</var> ...]]</code></td></tr>
678 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
679 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
680 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
682 <p>This directive allows remote servers to be mapped into the space of
683 the local server; the local server does not act as a proxy in the
684 conventional sense, but appears to be a mirror of the remote
685 server. <var>path</var> is the name of a local virtual path; <var>url</var>
686 is a partial URL for the remote server and cannot include a query
689 <div class="warning">The <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> directive should
690 usually be set <strong>off</strong> when using
691 <code class="directive">ProxyPass</code>.</div>
693 <p>Suppose the local server has address <code>http://example.com/</code>;
696 <div class="example"><p><code>
697 ProxyPass /mirror/foo/ http://backend.example.com/
700 <p>will cause a local request for
701 <code>http://example.com/mirror/foo/bar</code> to be internally converted
702 into a proxy request to <code>http://backend.example.com/bar</code>.</p>
704 <div class="warning">
705 <p>If the first argument ends with a trailing <strong>/</strong>, the second
706 argument should also end with a trailing <strong>/</strong> and vice
707 versa. Otherwise the resulting requests to the backend may miss some
708 needed slashes and do not deliver the expected results.
712 <p>The <code>!</code> directive is useful in situations where you don't want
713 to reverse-proxy a subdirectory, <em>e.g.</em></p>
715 <div class="example"><p><code>
716 ProxyPass /mirror/foo/i !<br />
717 ProxyPass /mirror/foo http://backend.example.com
720 <p>will proxy all requests to <code>/mirror/foo</code> to
721 <code>backend.example.com</code> <em>except</em> requests made to
722 <code>/mirror/foo/i</code>.</p>
724 <div class="note"><h3>Note</h3>
725 <p>Order is important. you need to put the exclusions <em>before</em> the
726 general <code class="directive">ProxyPass</code> directive.</p>
729 <p>As of Apache 2.1, the ability to use pooled connections to a backend
730 server is available. Using the <code>key=value</code> parameters it is
731 possible to tune this connection pooling. The default for a <code>Hard
732 Maximum</code> for the number of connections is the number of threads per
733 process in the active MPM. In the Prefork MPM, this is always 1, while with
734 the Worker MPM it is controlled by the
735 <code class="directive">ThreadsPerChild</code>.</p>
737 <p>Setting <code>min</code> will determine how many connections will always
738 be open to the backend server. Upto the Soft Maximum or <code>smax</code>
739 number of connections will be created on demand. Any connections above
740 <code>smax</code> are subject to a time to live or <code>ttl</code>. Apache
741 will never create more than the Hard Maximum or <code>max</code> connections
742 to the backend server.</p>
744 <div class="example"><p><code>
745 ProxyPass /example http://backend.example.com smax=5 max=20 ttl=120 retry=300
749 <tr><th>Parameter</th>
751 <th>Description</th></tr>
754 <td>Minumum number of connections that will always
755 be open to the backend server.</td></tr>
758 <td>Hard Maximum number of connections that will be
759 allowed to the backend server. The default for a Hard Maximum
760 for the number of connections is the number of threads per process in the
761 active MPM. In the Prefork MPM, this is always 1, while with the Worker MPM
762 it is controlled by the <code class="directive">ThreadsPerChild</code>.
763 Apache will never create more than the Hard Maximum connections
764 to the backend server.</td></tr>
767 <td>Upto the Soft Maximum
768 number of connections will be created on demand. Any connections above
769 <code>smax</code> are subject to a time to live or <code>ttl</code>.
773 <td>If set this will be the maximum time to wait for a free
774 connection in the connection pool. If there are no free connections
775 in the pool the Apache will return <code>SERVER_BUSY</code> status to
778 <tr><td>flushpackets</td>
780 <td>Determines whether the proxy module will auto-flush the output
781 brigade after each "chunk" of data. 'off' means that it will flush
782 only when needed, 'on' means after each chunk is sent and
783 'auto' means poll/wait for a period of time and flush if
784 no input has been received for 'flushwait' milliseconds.
785 Currently this is in effect only for AJP.
787 <tr><td>flushwait</td>
789 <td>The time to wait for additional input, in milliseconds, before
790 flushing the output brigade if 'flushpackets' is 'auto'.
792 <tr><td>keepalive</td>
794 <td>This parameter should be used when you have a firewall between your
795 Apache and the backend server, who tend to drop inactive connections.
796 This flag will tell the Operating System to send <code>KEEP_ALIVE</code>
797 messages on inactive connections (interval depends on global OS settings,
798 generally 120ms), and thus prevent the firewall to drop the connection.
799 To enable keepalive set this property value to <code>On</code>.
803 <td>Sets the load balancer cluster set that the worker is a member
804 of. The load balancer will try all members of a lower numbered
805 lbset before trying higher numbered ones.
809 <td>Ping property told webserver to send a <code>CPING</code>
810 request on ajp13 connection before forwarding to it a request.
811 The parameter is the delay in seconds to wait for the
812 <code>CPONG</code> reply.
813 This features has been added to avoid problem with hung and
814 busy Tomcat's and require ajp13 ping/pong support which has
815 been implemented on Tomcat 3.3.2+, 4.1.28+ and 5.0.13+.
816 It will inrease the network traffic during the normal operation
817 which could be an issue for you, but it will lower down the
818 traffic in case some of the cluster nodes are down or buys.
819 Currently this is in effect only for AJP.
821 <tr><td>redirect</td>
823 <td>Redirection Route of the worker. This value is usually
824 set dynamically to enable safe removal of the node from
825 the cluster. If set all requests without session id will be
826 redirected to the BalancerMember that has route parametar
831 <td>Connection pool worker retry timeout in seconds.
832 If the connection pool worker to the backend server is in the error state,
833 Apache will not forward any requests to that server until the timeout
834 expires. This enables to shut down the backend server for maintenance,
835 and bring it back online later.
839 <td>Route of the worker when used inside load balancer.
840 The route is a value appended to seesion id.
844 <td>Single letter value defining the initial status of
845 this worker: 'D' is disabled, 'S' is stopped, 'H' is hot-standby
846 and 'E' is in an error state. Status can be set (which is the default)
847 by prepending with '+' or cleared by prepending with '-'.
848 Thus, a setting of 'S-E' sets this worker to Stopped and
849 clears the in-error flag.
852 <td><code class="directive">Timeout</code></td>
853 <td>Connection timeout in seconds.
854 If not set the Apache will wait until the free connection
855 is available. This directive is used for limiting the number
856 of connections to the backend server together with <code>max</code>
861 <td>Time To Live for the inactive connections above the
862 <code>smax</code> connections in seconds. Apache will close all
863 connections that has not been used inside that time period.
868 <p>If the Proxy directive scheme starts with the
869 <code>balancer://</code> then a virtual worker that does not really
870 communicate with the backend server will be created. Instead it is responsible
871 for the management of several "real" workers. In that case the special set of
872 parameters can be add to this virtual worker. See <code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code>
873 for more information about how the balancer works.
876 <tr><th>Parameter</th>
878 <th>Description</th></tr>
879 <tr><td>lbmethod</td>
881 <td>Balancer load-balance method. Select the load-balancing scheduler
882 method to use. Either <code>byrequests</code>, to perform weighted
883 request counting or <code>bytraffic</code>, to perform weighted
884 traffic byte count balancing. Default is <code>byrequests</code>.
886 <tr><td>maxattempts</td>
888 <td>Maximum number of failover attempts before giving up.
890 <tr><td>nofailover</td>
892 <td>If set to <code>On</code> the session will break if the worker is in
893 error state or disabled. Set this value to On if backend servers do not
894 support session replication.
896 <tr><td>stickysession</td>
898 <td>Balancer sticky session name. The value is usually set to something
899 like <code>JSESSIONID</code> or <code>PHPSESSIONID</code>,
900 and it depends on the backend application server that support sessions.
904 <td>Balancer timeout in seconds. If set this will be the maximum time
905 to wait for a free worker. Default is not to wait.
909 <p>A sample balancer setup</p>
910 <div class="example"><p><code>
911 ProxyPass /special-area http://special.example.com/ smax=5 max=10<br />
912 ProxyPass / balancer://mycluster/ stickysession=jsessionid nofailover=On<br />
913 <Proxy balancer://mycluster><br />
914 <span class="indent">
915 BalancerMember http://1.2.3.4:8009<br />
916 BalancerMember http://1.2.3.5:8009 smax=10<br />
917 # Less powerful server, don't send as many requests there<br />
918 BalancerMember http://1.2.3.6:8009 smax=1 loadfactor=20<br />
923 <p>Setting up a hot-standby, that will only be used if no other
924 members are available</p>
925 <div class="example"><p><code>
926 ProxyPass / balancer://hotcluster/ <br />
927 <Proxy balancer://hotcluster><br />
928 <span class="indent">
929 BalancerMember http://1.2.3.4:8009 loadfactor=1<br />
930 BalancerMember http://1.2.3.5:8009 loadfactor=2<br />
931 # The below is the hot standby<br />
932 BalancerMember http://1.2.3.6:8009 status=+H<br />
933 ProxySet lbmethod=bytraffic
939 <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
940 directory is obtained from the <code class="directive"><a href="../mod/core.html#location"><Location></a></code>.</p>
942 <p>If you require a more flexible reverse-proxy configuration, see the
943 <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> directive with the
944 <code>[P]</code> flag.</p>
947 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
948 <div class="directive-section"><h2><a name="ProxyPassInterpolateEnv" id="ProxyPassInterpolateEnv">ProxyPassInterpolateEnv</a> <a name="proxypassinterpolateenv" id="proxypassinterpolateenv">Directive</a></h2>
949 <table class="directive">
950 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enable Environment Variable interpolation in Reverse Proxy configurations</td></tr>
951 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassInterpolateEnv On|Off</code></td></tr>
952 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyPassInterpolateEnv Off</code></td></tr>
953 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
954 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
955 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
956 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in trunk only</td></tr>
958 <p>This directive enables reverse proxies to be dynamically
959 configured using environment variables, which may be set by
960 another module such as <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>.
961 It affects the <code class="directive">ProxyPass</code>,
962 <code class="directive">ProxyPassReverse</code>,
963 <code class="directive">ProxyPassReverseCookieDomain</code>, and
964 <code class="directive">ProxyPassReverseCookiePath</code> directives,
965 and causes them to substitute the value of an environment
966 variable <code>varname</code> for the string <code>${varname}</code>
967 in configuration directives.</p>
968 <p>Keep this turned off (for server performance) unless you need it!</p>
971 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
972 <div class="directive-section"><h2><a name="ProxyPassReverse" id="ProxyPassReverse">ProxyPassReverse</a> <a name="proxypassreverse" id="proxypassreverse">Directive</a></h2>
973 <table class="directive">
974 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Adjusts the URL in HTTP response headers sent from a reverse
975 proxied server</td></tr>
976 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassReverse [<var>path</var>] <var>url</var></code></td></tr>
977 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
978 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
979 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
981 <p>This directive lets Apache adjust the URL in the <code>Location</code>,
982 <code>Content-Location</code> and <code>URI</code> headers on HTTP redirect
983 responses. This is essential when Apache is used as a reverse proxy to avoid
984 by-passing the reverse proxy because of HTTP redirects on the backend
985 servers which stay behind the reverse proxy.</p>
987 <p>Only the HTTP response headers specifically mentioned above
988 will be rewritten. Apache will not rewrite other response
989 headers, nor will it rewrite URL references inside HTML pages.
990 This means that if the proxied content contains absolute URL
991 references, they will by-pass the proxy. A third-party module
992 that will look inside the HTML and rewrite URL references is Nick
993 Kew's <a href="http://apache.webthing.com/mod_proxy_html/">mod_proxy_html</a>.</p>
995 <p><var>path</var> is the name of a local virtual path. <var>url</var> is a
996 partial URL for the remote server - the same way they are used for the
997 <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.</p>
999 <p>For example, suppose the local server has address
1000 <code>http://example.com/</code>; then</p>
1002 <div class="example"><p><code>
1003 ProxyPass /mirror/foo/ http://backend.example.com/<br />
1004 ProxyPassReverse /mirror/foo/ http://backend.example.com/<br />
1005 ProxyPassReverseCookieDomain backend.example.com public.example.com<br />
1006 ProxyPassReverseCookiePath / /mirror/foo/
1009 <p>will not only cause a local request for the
1010 <code>http://example.com/mirror/foo/bar</code> to be internally converted
1011 into a proxy request to <code>http://backend.example.com/bar</code>
1012 (the functionality <code>ProxyPass</code> provides here). It also takes care
1013 of redirects the server <code>backend.example.com</code> sends: when
1014 <code>http://backend.example.com/bar</code> is redirected by him to
1015 <code>http://backend.example.com/quux</code> Apache adjusts this to
1016 <code>http://example.com/mirror/foo/quux</code> before forwarding the HTTP
1017 redirect response to the client. Note that the hostname used for
1018 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>
1020 <p>Note that this <code class="directive">ProxyPassReverse</code> directive can
1021 also be used in conjunction with the proxy pass-through feature
1022 (<code>RewriteRule ... [P]</code>) from <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>
1023 because it doesn't depend on a corresponding <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.</p>
1025 <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
1026 directory is obtained from the <code class="directive"><a href="../mod/core.html#location"><Location></a></code>.</p>
1029 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1030 <div class="directive-section"><h2><a name="ProxyPassReverseCookieDomain" id="ProxyPassReverseCookieDomain">ProxyPassReverseCookieDomain</a> <a name="proxypassreversecookiedomain" id="proxypassreversecookiedomain">Directive</a></h2>
1031 <table class="directive">
1032 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Adjusts the Domain string in Set-Cookie headers from a reverse-
1033 proxied server</td></tr>
1034 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassReverseCookieDomain <var>internal-domain</var> <var>public-domain</var></code></td></tr>
1035 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1036 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1037 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1039 <p>Usage is basically similar to
1040 <code class="directive"><a href="#proxypassreverse">ProxyPassReverse</a></code>, but instead of
1041 rewriting headers that are a URL, this rewrites the <code>domain</code>
1042 string in <code>Set-Cookie</code> headers.</p>
1045 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1046 <div class="directive-section"><h2><a name="ProxyPassReverseCookiePath" id="ProxyPassReverseCookiePath">ProxyPassReverseCookiePath</a> <a name="proxypassreversecookiepath" id="proxypassreversecookiepath">Directive</a></h2>
1047 <table class="directive">
1048 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Adjusts the Path string in Set-Cookie headers from a reverse-
1049 proxied server</td></tr>
1050 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPassReverseCookiePath <var>internal-path</var> <var>public-path</var></code></td></tr>
1051 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</td></tr>
1052 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1053 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1055 <p>Usage is basically similar to
1056 <code class="directive"><a href="#proxypassreverse">ProxyPassReverse</a></code>, but instead of
1057 rewriting headers that are a URL, this rewrites the <code>path</code>
1058 string in <code>Set-Cookie</code> headers.</p>
1061 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1062 <div class="directive-section"><h2><a name="ProxyPreserveHost" id="ProxyPreserveHost">ProxyPreserveHost</a> <a name="proxypreservehost" id="proxypreservehost">Directive</a></h2>
1063 <table class="directive">
1064 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Use incoming Host HTTP request header for proxy
1066 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPreserveHost On|Off</code></td></tr>
1067 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyPreserveHost Off</code></td></tr>
1068 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1069 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1070 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1071 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.0.31 and later.</td></tr>
1073 <p>When enabled, this option will pass the Host: line from the incoming
1074 request to the proxied host, instead of the hostname specified in the
1075 <code class="directive">ProxyPass</code> line.</p>
1077 <p>This option should normally be turned <code>Off</code>. It is mostly
1078 useful in special configurations like proxied mass name-based virtual
1079 hosting, where the original Host header needs to be evaluated by the
1083 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1084 <div class="directive-section"><h2><a name="ProxyReceiveBufferSize" id="ProxyReceiveBufferSize">ProxyReceiveBufferSize</a> <a name="proxyreceivebuffersize" id="proxyreceivebuffersize">Directive</a></h2>
1085 <table class="directive">
1086 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Network buffer size for proxied HTTP and FTP
1087 connections</td></tr>
1088 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyReceiveBufferSize <var>bytes</var></code></td></tr>
1089 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyReceiveBufferSize 0</code></td></tr>
1090 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1091 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1092 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1094 <p>The <code class="directive">ProxyReceiveBufferSize</code> directive specifies an
1095 explicit (TCP/IP) network buffer size for proxied HTTP and FTP connections,
1096 for increased throughput. It has to be greater than <code>512</code> or set
1097 to <code>0</code> to indicate that the system's default buffer size should
1100 <div class="example"><h3>Example</h3><p><code>
1101 ProxyReceiveBufferSize 2048
1105 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1106 <div class="directive-section"><h2><a name="ProxyRemote" id="ProxyRemote">ProxyRemote</a> <a name="proxyremote" id="proxyremote">Directive</a></h2>
1107 <table class="directive">
1108 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Remote proxy used to handle certain requests</td></tr>
1109 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyRemote <var>match</var> <var>remote-server</var></code></td></tr>
1110 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1111 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1112 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1114 <p>This defines remote proxies to this proxy. <var>match</var> is either the
1115 name of a URL-scheme that the remote server supports, or a partial URL
1116 for which the remote server should be used, or <code>*</code> to indicate
1117 the server should be contacted for all requests. <var>remote-server</var> is
1118 a partial URL for the remote server. Syntax:</p>
1120 <div class="example"><p><code>
1121 <dfn>remote-server</dfn> =
1122 <var>scheme</var>://<var>hostname</var>[:<var>port</var>]
1125 <p><var>scheme</var> is effectively the protocol that should be used to
1126 communicate with the remote server; only <code>http</code> is supported by
1129 <div class="example"><h3>Example</h3><p><code>
1130 ProxyRemote http://goodguys.com/ http://mirrorguys.com:8000<br />
1131 ProxyRemote * http://cleversite.com<br />
1132 ProxyRemote ftp http://ftpproxy.mydomain.com:8080
1135 <p>In the last example, the proxy will forward FTP requests, encapsulated
1136 as yet another HTTP proxy request, to another proxy which can handle
1139 <p>This option also supports reverse proxy configuration - a backend
1140 webserver can be embedded within a virtualhost URL space even if that
1141 server is hidden by another forward proxy.</p>
1144 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1145 <div class="directive-section"><h2><a name="ProxyRemoteMatch" id="ProxyRemoteMatch">ProxyRemoteMatch</a> <a name="proxyremotematch" id="proxyremotematch">Directive</a></h2>
1146 <table class="directive">
1147 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Remote proxy used to handle requests matched by regular
1148 expressions</td></tr>
1149 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyRemoteMatch <var>regex</var> <var>remote-server</var></code></td></tr>
1150 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1151 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1152 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1154 <p>The <code class="directive">ProxyRemoteMatch</code> is identical to the
1155 <code class="directive"><a href="#proxyremote">ProxyRemote</a></code> directive, except the
1156 first argument is a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>
1157 match against the requested URL.</p>
1160 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1161 <div class="directive-section"><h2><a name="ProxyRequests" id="ProxyRequests">ProxyRequests</a> <a name="proxyrequests" id="proxyrequests">Directive</a></h2>
1162 <table class="directive">
1163 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables forward (standard) proxy requests</td></tr>
1164 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyRequests On|Off</code></td></tr>
1165 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyRequests Off</code></td></tr>
1166 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1167 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1168 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1170 <p>This allows or prevents Apache from functioning as a forward proxy
1171 server. (Setting ProxyRequests to <code>Off</code> does not disable use of
1172 the <code class="directive"><a href="#proxypass">ProxyPass</a></code> directive.)</p>
1174 <p>In a typical reverse proxy configuration, this option should be set to
1175 <code>Off</code>.</p>
1177 <p>In order to get the functionality of proxying HTTP or FTP sites, you
1178 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>
1179 (or both) present in the server.</p>
1181 <div class="warning"><h3>Warning</h3>
1182 <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
1183 both to your network and to the Internet at large.</p>
1187 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1188 <div class="directive-section"><h2><a name="ProxyTimeout" id="ProxyTimeout">ProxyTimeout</a> <a name="proxytimeout" id="proxytimeout">Directive</a></h2>
1189 <table class="directive">
1190 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Network timeout for proxied requests</td></tr>
1191 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyTimeout <var>seconds</var></code></td></tr>
1192 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyTimeout 300</code></td></tr>
1193 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1194 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1195 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1196 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.0.31 and later</td></tr>
1198 <p>This directive allows a user to specifiy a timeout on proxy requests.
1199 This is useful when you have a slow/buggy appserver which hangs, and you
1200 would rather just return a timeout and fail gracefully instead of waiting
1201 however long it takes the server to return.</p>
1204 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
1205 <div class="directive-section"><h2><a name="ProxyVia" id="ProxyVia">ProxyVia</a> <a name="proxyvia" id="proxyvia">Directive</a></h2>
1206 <table class="directive">
1207 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Information provided in the <code>Via</code> HTTP response
1208 header for proxied requests</td></tr>
1209 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyVia On|Off|Full|Block</code></td></tr>
1210 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyVia Off</code></td></tr>
1211 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
1212 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
1213 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_proxy</td></tr>
1215 <p>This directive controls the use of the <code>Via:</code> HTTP
1216 header by the proxy. Its intended use is to control the flow of
1217 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
1218 14.45 for an explanation of <code>Via:</code> header lines.</p>
1221 <li>If set to <code>Off</code>, which is the default, no special processing
1222 is performed. If a request or reply contains a <code>Via:</code> header,
1223 it is passed through unchanged.</li>
1225 <li>If set to <code>On</code>, each request and reply will get a
1226 <code>Via:</code> header line added for the current host.</li>
1228 <li>If set to <code>Full</code>, each generated <code>Via:</code> header
1229 line will additionally have the Apache server version shown as a
1230 <code>Via:</code> comment field.</li>
1232 <li>If set to <code>Block</code>, every proxy request will have all its
1233 <code>Via:</code> header lines removed. No new <code>Via:</code> header will
1239 <div class="bottomlang">
1240 <p><span>Available Languages: </span><a href="../en/mod/mod_proxy.html" title="English"> en </a> |
1241 <a href="../ja/mod/mod_proxy.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a></p>
1242 </div><div id="footer">
1243 <p class="apache">Copyright 2006 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>
1244 <p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="../faq/">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p></div>