mod_proxy.html.en

Apache官方在今天放出产品系列2.2的最新版本2.2.11的源码包 最流行的HTTP服务器软件之一

      <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 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 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>

      <div class="example"><p><code>
        &lt;Location /buggyappserver/&gt;<br />
        <span class="indent">
          ProxyPass http://buggyappserver:7001/foo/<br />
          SetEnv force-proxy-request-1.0 1<br />
          SetEnv proxy-nokeepalive 1<br />
        </span>
        &lt;/Location&gt;
      </code></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="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>

    </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>

   </div>
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<div class="directive-section"><h2><a name="AllowCONNECT" id="AllowCONNECT">AllowCONNECT</a> <a name="allowconnect" id="allowconnect">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Ports that are allowed to <code>CONNECT</code> through the
proxy</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AllowCONNECT <var>port</var> [<var>port</var>] ...</code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AllowCONNECT 443 563</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">AllowCONNECT</code> directive specifies a list
    of port numbers to which the proxy <code>CONNECT</code> method may
    connect.  Today's browsers use this method when a <code>https</code>
    connection is requested and proxy tunneling over HTTP is in effect.</p>

    <p>By default, only the default https port (<code>443</code>) and the
    default snews port (<code>563</code>) are enabled. Use the
    <code class="directive">AllowCONNECT</code> directive to override this default and
    allow connections to the listed ports only.</p>

    <p>Note that you'll need to have <code class="module"><a href="../mod/mod_proxy_connect.html">mod_proxy_connect</a></code> present
    in the server in order to get the support for the <code>CONNECT</code> at
    all.</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>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 2.2
        and later.</td></tr>
</table>
    <p>This directive adds a member to a load balancing group. It must be used
    within a <code>&lt;Proxy <var>balancer://</var>...&gt;</code> container
    directive, and can take any of the parameters available to
    <code class="directive"><a href="#proxypass">ProxyPass</a></code> directives.</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 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><p><code>
      ProxyRemote  *  http://firewall.example.com:81<br />
      NoProxy         .example.com 192.168.112.0/21
    </code></p></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 .apache.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 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="#ipadr">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>