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    <h1 align="CENTER">Apache module mod_proxy</h1>

    <p>This module provides for an <strong>HTTP 1.1</strong>
    caching proxy server.</p>

    <p><a href="module-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Extension<br />
     <a href="module-dict.html#SourceFile"
    rel="Help"><strong>Source File:</strong></a> mod_proxy.c<br />
     <a href="module-dict.html#ModuleIdentifier"
    rel="Help"><strong>Module Identifier:</strong></a>
    proxy_module<br />
     <a href="module-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> Available in
    Apache 1.1 and later.</p>

    <h2>Summary</h2>
    This module implements a proxy/cache for Apache. It implements
    proxying capability for <code>FTP</code>, <code>CONNECT</code>
    (for SSL), <code>HTTP/0.9</code>, <code>HTTP/1.0</code>, and
    (as of Apache 1.3.23) <code>HTTP/1.1</code>.
    The module can be configured to connect to other proxy modules
    for these and other protocols. 

    <p>This module was experimental in Apache 1.1.x. As of Apache
    1.2, mod_proxy stability is <em>greatly</em> improved.</p>

    <p><strong>Warning:</strong> Do not enable proxying with <a
    href="#proxyrequests">ProxyRequests</a> 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>

    <h2>Directives</h2>

    <ul>
      <li><a href="#proxyrequests">ProxyRequests</a></li>

      <li><a href="#proxyremote">ProxyRemote</a></li>

      <li><a href="#proxypass">ProxyPass</a></li>

      <li><a href="#proxypassreverse">ProxyPassReverse</a></li>

      <li><a href="#proxyblock">ProxyBlock</a></li>

      <li><a href="#allowconnect">AllowCONNECT</a></li>

      <li><a href="#proxyreceivebuffersize">ProxyReceiveBufferSize</a></li>

      <li><a href="#proxyiobuffersize">ProxyIOBufferSize</a></li>

      <li><a href="#noproxy">NoProxy</a></li>

      <li><a href="#proxydomain">ProxyDomain</a></li>

      <li><a href="#proxyvia">ProxyVia</a></li>

      <li><a href="#cacheroot">CacheRoot</a></li>

      <li><a href="#cachesize">CacheSize</a></li>

      <li><a href="#cachemaxexpire">CacheMaxExpire</a></li>

      <li><a href="#cachedefaultexpire">CacheDefaultExpire</a></li>

      <li><a
      href="#cachelastmodifiedfactor">CacheLastModifiedFactor</a></li>

      <li><a href="#cachegcinterval">CacheGcInterval</a></li>

      <li><a href="#cachedirlevels">CacheDirLevels</a></li>

      <li><a href="#cachedirlength">CacheDirLength</a></li>

      <li><a
      href="#cacheforcecompletion">CacheForceCompletion</a></li>

      <li><a href="#nocache">NoCache</a></li>
    </ul>

    <h2><a id="configs" name="configs">Common configuration
    topics</a></h2>

    <ul>
      <li><a href="#forwardreverse">Forward and Reverse Proxies</a></li>

      <li><a href="#examples">Basic Examples</a></li>

      <li><a href="#access">Controlling access to your
      proxy</a></li>

      <li><a href="#shortname">Using Netscape hostname
      shortcuts</a></li>

      <li><a href="#mimetypes">Why doesn't file type <em>xxx</em>
      download via FTP?</a></li>

      <li><a href="#type">How can I force an FTP ASCII
      download of File <em>xxx</em>?</a></li>

      <li><a href="#percent2fhack">How can I access
      FTP files outside of my home directory?</a></li>

      <li><a href="#ftppass">How can I hide the
      FTP cleartext password in my browser's URL line?</a></li>

      <li><a href="#startup">Why does Apache start more slowly when
      using the proxy module?</a></li>

      <li><a href="#socks">Can I use the Apache proxy module with
      my SOCKS proxy?</a></li>

      <li><a href="#intranet">What other functions are useful for
      an intranet proxy server?</a></li>
    </ul>

<h2><a name="forwardreverse" id="forwardreverse">Forward and Reverse Proxies</a></h2>
      <p>Apache can be configured in both a <dfn>forward</dfn> and
      <dfn>reverse</dfn> proxy 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 and 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 to reduce
      network usage.</p>

      <p>The forward proxy is activated using the <code><a
      href="#proxyrequests">ProxyRequests</a></code> directive.
      Because forward proxys 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>, 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 name-space of the reverse
      proxy.  The reverse proxy then decides where to send those
      requests, and returns the content as if it was 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><a
      href="#proxypass">ProxyPass</a></code> directive or the
      <code>[P]</code> flag to the <code><a
      href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code>
      directive.  It is <strong>not</strong> necessary to turn
      <code><a href="#proxyrequests">ProxyRequests</a></code> on in
      order to configure a reverse proxy.</p> 

<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>

    <h3>Forward Proxy</h3><p><code>
    ProxyRequests On<br />
    ProxyVia On<br />
    <br />
    &lt;Directory proxy:*&gt;<br />
    
      Order deny,allow<br />
      Deny from all<br />
      Allow from internal.example.com<br />
    
    &lt;/Directory&gt;<br />
    <br />
    CacheRoot "/usr/local/apache/proxy"<br />
    CacheSize 5<br />
    CacheGcInterval 4<br />
    CacheMaxExpire 24<br />
    CacheLastModifiedFactor 0.1<br />
    CacheDefaultExpire 1<br />
    NoCache a-domain.com another-domain.edu joes.garage-sale.com
    </code></p>

    <h3>Reverse Proxy</h3><p><code>
    ProxyRequests Off<br />
    <br />
    ProxyPass /foo http://foo.example.com/bar<br />
    ProxyPassReverse /foo http://foo.example.com/bar
    </code></p>

    <h2><a id="access" name="access">Controlling access to your
    proxy</a></h2>
    You can control who can access your proxy via the normal
    &lt;Directory&gt; control block using the following example: 
<pre>
&lt;Directory proxy:*&gt;
Order Deny,Allow
Deny from all
Allow from yournetwork.example.com
&lt;/Directory&gt;
</pre>

    <p>A &lt;Files&gt; block will also work, and is the only method
    known to work for all possible URLs in Apache versions earlier
    than 1.2b10.</p>

    <p>For more information, see <a
    href="mod_access.html">mod_access</a>.</p>

      <p>Strictly limiting access is essential if you are using a
      forward proxy (using the <code><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><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>

    <h2><a id="shortname" name="shortname">Using Netscape hostname
    shortcuts</a></h2>
    There is an optional patch to the proxy module to allow
    Netscape-like hostname shortcuts to be used. It's available
    from the <a
    href="http://www.apache.org/dist/httpd/contrib/patches/1.2/netscapehost.patch">
    <samp>contrib/patches/1.2</samp></a> directory on the Apache
    Web site. 

    <h2><a id="mimetypes" name="mimetypes">Why doesn't file type
    <em>xxx</em> download via FTP?</a></h2>
    You probably don't have that particular file type defined as
    <em>application/octet-stream</em> in your proxy's mime.types
    configuration file. A useful line can be 
<pre>
application/octet-stream        bin dms lha lzh exe class tgz taz
</pre>

    <h2><a id="type" name="type">How can I force an FTP ASCII
    download of File <em>xxx</em>?</a></h2>
    In the rare situation where you must download a specific file
    using the FTP <strong>ASCII</strong> transfer method (while the
    default transfer is in <strong>binary</strong> mode), you can
    override mod_proxy's default by suffixing the request with
    <samp>;type=a</samp> to force an ASCII transfer.
    (FTP Directory listings are always executed in ASCII mode, however.)

    <h2><a id="percent2fhack" name="percent2fhack">How can I access
    FTP files outside of my home directory?</a></h2>
    <p>
     A FTP URI is interpreted relative to the home directory of
     the user who is logging in. Alas, to reach higher directory
     levels you cannot use  /../, as the dots are interpreted by the
     browser and not actually sent to the FTP server. To address
     this problem, the so called "Squid %2f hack" was implemented in
     the Apache FTP proxy; it is a solution which is also used by
     other popular proxy servers like the
     <a href="http://www.squid-cache.org/">Squid Proxy Cache</a>.
     By prepending /%2f to the path of your request, you can make
     such a proxy change the FTP starting directory to / (instead
     of the home directory). <br />
     <b>Example:</b> To retrieve the file <code>/etc/motd</code>,
     you would use the URL <blockquote>
     <code>ftp://<em>user@host</em>/%2f/etc/motd</code></blockquote>
    </p>

    <h2><a id="ftppass" name="ftppass">How can I hide the FTP
    cleartext password in my browser's URL line?</a></h2>
    <p>
     To log in to an FTP server by username and password, Apache
     uses different strategies.
     In absense of a user name and password in the URL altogether,
     Apache sends an anonymous login to the FTP server, i.e.,
     <blockquote><code>
       user: anonymous<br />
       password: apache_proxy@
     </code></blockquote>
     This works for all popular FTP servers which are configured for
     anonymous access.<br>
     For a personal login with a specific username, you can embed
     the user name into the URL, like in:
     <code>ftp://<em>username@host</em>/myfile</code>. If the FTP server
     asks for a password when given this username (which it should),
     then Apache will reply with a [401 Authorization required] response,
     which causes the Browser to pop up the username/password dialog.
     Upon entering the password, the connection attempt is retried,
     and if successful, the requested resource is presented.
     The advantage of this procedure is that your browser does not
     display the password in cleartext (which it would if you had used
     <code>ftp://<em>username:password@host</em>/myfile</code> in
     the first place).
     <br />
     <b>Note</b> that the password which is transmitted in such a way
     is not encrypted on its way. It travels between your browser and
     the Apache proxy server in a base64-encoded cleartext string, and
     between the Apache proxy and the FTP server as plaintext. You should
     therefore think twice before accessing your FTP server via HTTP
     (or before accessing your personal files via FTP at all!) When
     using unsecure channels, an eavesdropper might intercept your
     password on its way.
    </p>


    <h2><a id="startup" name="startup">Why does Apache start more
    slowly when using the proxy module?</a></h2>
    If you're using the <code>ProxyBlock</code> or
    <code>NoCache</code> directives, 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. 

    <h2><a id="socks" name="socks">Can I use the Apache proxy
    module with my SOCKS proxy?</a></h2>
    Yes. Just build Apache with the rule <code>SOCKS4=yes</code> in
    your <em>Configuration</em> file, and follow the instructions
    there. SOCKS5 capability can be added in a similar way (there's
    no <code>SOCKS5</code> rule yet), so use the
    <code>EXTRA_LDFLAGS</code> definition, or build Apache normally
    and run it with the <em>runsocks</em> wrapper provided with
    SOCKS5, if your OS supports dynamically linked libraries. 

    <p>Some users have reported problems when using SOCKS version
    4.2 on Solaris. The problem was solved by upgrading to SOCKS
    4.3.</p>

    <p>Remember that you'll also have to grant access to your
    Apache proxy machine by permitting connections on the
    appropriate ports in your SOCKS daemon's configuration.</p>

    <h2><a id="intranet" name="intranet">What other functions are
    useful for an intranet proxy server?</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 <a href="#proxyremote">ProxyRemote</a>
    directive to forward the respective <em>scheme</em> to
    the firewall proxy).
    However, when it has to access resources within the intranet,
    it can bypass the firewall when accessing hosts. The <a
    href="#noproxy">NoProxy</a> 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 "http://somehost.my.dom.ain/". Some commercial proxy
    servers let them get away with this and simply serve the
    request, implying a configured local domain. When the <a
    href="#proxydomain">ProxyDomain</a> 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>
    <hr />

    <h2><a id="proxyrequests"
    name="proxyrequests">ProxyRequests</a> directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ProxyRequests
    on|off<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>ProxyRequests
    Off</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> <em>Not
    applicable</em><br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Base<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_proxy<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> ProxyRequests is
    only available in Apache 1.1 and later. 

    <p>This allows or prevents Apache from functioning as a forward proxy
    server. Setting ProxyRequests to 'off' does not disable use of
    the <a href="#proxypass">ProxyPass</a> directive.</p>

    <p><strong>Warning:</strong> Do not enable proxying 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>

    <hr />

    <h2><a id="proxyremote" name="proxyremote">ProxyRemote</a>
    directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ProxyRemote <em>match
    remote-server</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <em>None</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> <em>Not
    applicable</em><br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Base<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_proxy<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> ProxyRemote is
    only available in Apache 1.1 and later. 

    <p>This defines remote proxies to this proxy. <em>match</em> 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 '*' to indicate the server should be contacted for
    all requests. <em>remote-server</em> is a partial URL for the
    remote server. Syntax:</p>
<pre>
  remote-server = protocol://hostname[:port]
</pre>
    <em>protocol</em> is the protocol that should be used to
    communicate with the remote server; only "http" is supported by
    this module. 

    <p>Example:</p>
<pre>
  ProxyRemote http://goodguys.com/ http://mirrorguys.com:8000
  ProxyRemote * http://cleversite.com
  ProxyRemote ftp http://ftpproxy.mydomain.com:8080
</pre>
    In the last example, the proxy will forward FTP requests,
    encapsulated as yet another HTTP proxy request, to another
    proxy which can handle them. 
    <hr />

    <h2><a id="proxypass" name="proxypass">ProxyPass</a>
    directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ProxyPass <em>path
    url</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <em>None</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> <em>Not
    applicable</em><br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Base<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_proxy<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> ProxyPass is
    only available in Apache 1.1 and later. 

    <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. <em>path</em> is the name of a local virtual
    path; <em>url</em> is a partial URL for the remote server.</p>

    <p>Suppose the local server has address
    <samp>http://wibble.org/</samp>; then</p>
<pre>
   ProxyPass /mirror/foo/ http://foo.com/
</pre>
    <p>will cause a local request for the
    &lt;<samp>http://wibble.org/mirror/foo/bar</samp>&gt; to be
    internally converted into a proxy request to
    &lt;<samp>http://foo.com/bar</samp>&gt;.</p>

    <p><strong>Warning:</strong> The <code><a
    href="#proxyrequests">ProxyRequests</a></code> directive should
    usually be set <strong>off</strong> when using <code
    class="directive">ProxyPass</code>.

    <hr />

    <h2><a id="proxypassreverse"
    name="proxypassreverse">ProxyPassReverse</a> directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ProxyPassReverse
    <em>path url</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <em>None</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> <em>Not
    applicable</em><br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Base<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_proxy<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> ProxyPassReverse
    is only available in Apache 1.3b6 and later. 

    <p>This directive lets Apache adjust the URL in the
    <tt>Location</tt> header on HTTP redirect responses. For
    instance this is essential when Apache is used as a reverse
    proxy to avoid by-passing the reverse proxy because of HTTP
    redirects on the backend servers which stay behind the reverse
    proxy.</p>

    <p><em>path</em> is the name of a local virtual path.<br />
     <em>url</em> is a partial URL for the remote server - the same
    way they are used for the <tt>ProxyPass</tt> directive.</p>

    <p>Example:<br />
     Suppose the local server has address
    <samp>http://wibble.org/</samp>; then</p>
<pre>
   ProxyPass         /mirror/foo/ http://foo.com/
   ProxyPassReverse  /mirror/foo/ http://foo.com/
</pre>
    will not only cause a local request for the
    &lt;<samp>http://wibble.org/mirror/foo/bar</samp>&gt; to be
    internally converted into a proxy request to
    &lt;<samp>http://foo.com/bar</samp>&gt; (the functionality
    <samp>ProxyPass</samp> provides here). It also takes care of
    redirects the server foo.com sends: when
    <samp>http://foo.com/bar</samp> is redirected by him to
    <samp>http://foo.com/quux</samp> Apache adjusts this to
    <samp>http://wibble.org/mirror/foo/quux</samp> before
    forwarding the HTTP redirect response to the client. 

    <p>Note that this <samp>ProxyPassReverse</samp> directive can
    also be used in conjunction with the proxy pass-through feature
    ("<samp>RewriteRule ... [P]</samp>") from <a
    href="mod_rewrite.html#RewriteRule"><tt>mod_rewrite</tt></a>
    because its doesn't depend on a corresponding
    <samp>ProxyPass</samp> directive.</p>
    <hr />

    <h2><a id="allowconnect" name="allowconnect">AllowCONNECT</a>
    directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> AllowCONNECT
    <em>port</em> [<em>port</em>] ...<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a>
    <em><samp>AllowCONNECT</samp> 443 563</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> <em>Not
    applicable</em><br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Base<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_proxy<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a>
    <samp>AllowCONNECT</samp> is only available in Apache 1.3.2 and
    later. 

    <p>The <samp>AllowCONNECT</samp> directive specifies a list of
    port numbers to which the proxy <samp>CONNECT</samp> method may
    connect. Today's browsers use this method when a <em>https</em>
    connection is requested and proxy tunneling over <em>http</em>
    is in effect.<br />
     By default, only the default https port (443) and the default
    snews port (563) are enabled. Use the <samp>AllowCONNECT</samp>
    directive to override this default and allow connections to
    the listed ports only.</p>
    <hr />

    <h2><a id="proxyblock" name="proxyblock">ProxyBlock</a>
    directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ProxyBlock
    *|<em>word|host|domain</em> [<em>word|host|domain</em>]
    ...<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <em>None</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> <em>Not
    applicable</em><br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Base<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_proxy<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> ProxyBlock is
    only available in Apache 1.2 and later. 

    <p>The ProxyBlock 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. Example:</p>
<pre>
  ProxyBlock joes-garage.com some-host.co.uk rocky.wotsamattau.edu
</pre>
    'rocky.wotsamattau.edu' would also be matched if referenced by
    IP address. 

    <p>Note that 'wotsamattau' would also be sufficient to match
    'wotsamattau.edu'.</p>

    <p>Note also that</p>
<pre>
ProxyBlock *
</pre>
    blocks connections to all sites. 
    <hr />

    <h2><a id="proxyreceivebuffersize"
    name="proxyreceivebuffersize">ProxyReceiveBufferSize</a>
    directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ProxyReceiveBufferSize
    <em>bytes</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <em>None</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> <em>Not
    applicable</em><br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Base<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_proxy<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a>
    ProxyReceiveBufferSize is only available in Apache 1.3 and
    later. 

    <p>The ProxyReceiveBufferSize directive specifies an explicit
    network buffer size for outgoing HTTP and FTP connections, for
    increased throughput. It has to be greater than 512 or set to 0
    to indicate that the system's default buffer size should be
    used.</p>

    <p>Example:</p>
<pre>
  ProxyReceiveBufferSize 2048
</pre>
    <hr />

    <h2><a id="proxyiobuffersize"
    name="proxyiobuffersize">ProxyIOBufferSize</a>
    directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ProxyIOBufferSize
    <em>bytes</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <em>8192</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> <em>Not
    applicable</em><br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Base<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_proxy<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a>
    ProxyIOBufferSize is only available in Apache 1.3.24 and
    later. 

    <p>The ProxyIOBufferSize directive specifies the number of bytes
    that will be read from a remote HTTP or FTP server at one time.
    This directive is different from the ProxyReceiveBufferSize
    directive, which specifies the low level socket buffer size.
    </p>

    <p>
    When a response is received which fits entirely within the IO
    buffer size, the remote HTTP or FTP server socket will be closed
    before an attempt is made to write the response to the client.
    This ensures that the remote server does not remain connected
    unnecessarily while the response is delivered to a slow client.
    A high value for the IO buffer decreases the load on remote HTTP
    and FTP servers, at the expense of greater RAM footprint on the
    proxy.
    </p>

    <p>Example:</p>
<pre>
  ProxyIOBufferSize 131072
</pre>
    <hr />

    <h2><a id="noproxy" name="noproxy">NoProxy</a> directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> NoProxy <a
    href="#domain"><em>Domain</em></a>|<a
    href="#subnet"><em>SubNet</em></a>|<a
    href="#ipaddr"><em>IpAddr</em></a>|<a
    href="#hostname"><em>Hostname</em></a> [<a
    href="#domain"><em>Domain</em></a>|<a
    href="#subnet"><em>SubNet</em></a>|<a
    href="#ipaddr"><em>IpAddr</em></a>|<a
    href="#hostname"><em>Hostname</em></a>] ...<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <em>None</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> <em>Not
    applicable</em><br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Base<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_proxy<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> NoProxy is only
    available in Apache 1.3 and later. 

    <p>This directive is only useful for Apache proxy servers
    within intranets. The NoProxy 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
    ProxyRemote proxy server(s).</p>

    <p>Example:</p>
<pre>
  ProxyRemote  *  http://firewall.mycompany.com:81
  NoProxy         .mycompany.com 192.168.112.0/21 
</pre>
    The arguments to the NoProxy directive are one of the following
    type list: 

    <dl>
      <!-- ===================== Domain ======================= -->

      <dt><a id="domain" name="domain"><em>Domain</em></a></dt>

      <dd>A <em>Domain</em> 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 <em>Domain</em>).<br />
       Examples: <samp>.com</samp> <samp>.apache.org.</samp><br />
       To distinguish <em>Domain</em>s from <a
      href="#hostname"><em>Hostname</em></a>s (both syntactically
      and semantically; a DNS domain can have a DNS A record,
      too!), <em>Domain</em>s are always written with a leading
      period.<br />
       Note: Domain name comparisons are done without regard to the
      case, and <em>Domain</em>s are always assumed to be anchored
      in the root of the DNS tree, therefore two domains
      <samp>.MyDomain.com</samp> and <samp>.mydomain.com.</samp>
      (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. 
      <!-- ===================== SubNet ======================= -->
      </dd>

      <dt><a id="subnet" name="subnet"><em>SubNet</em></a></dt>

      <dd>
        A <em>SubNet</em> 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 <em>SubNet</em>. 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.)<br />
         Examples: 

        <dl>
          <dt><samp>192.168</samp> or <samp>192.168.0.0</samp></dt>

          <dd>the subnet 192.168.0.0 with an implied netmask of 16
          valid bits (sometimes used in the netmask form
          <samp>255.255.0.0</samp>)</dd>

          <dt><samp>192.168.112.0/21</samp></dt>

          <dd>the subnet <samp>192.168.112.0/21</samp> with a
          netmask of 21 valid bits (also used in the form
          255.255.248.0)</dd>
        </dl>
        As a degenerate case, a <em>SubNet</em> with 32 valid bits
        is the equivalent to an <em>IPAddr</em>, while a
        <em>SubNet</em> with zero valid bits (<em>e.g.</em>,
        0.0.0.0/0) is the same as the constant <em>_Default_</em>,
        matching any IP address. 
        <!-- ===================== IPAddr ======================= -->
      </dd>

      <dt><a id="ipaddr" name="ipaddr"><em>IPAddr</em></a></dt>

      <dd>
        A <em>IPAddr</em> 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.<br />
         Example: 192.168.123.7<br />
         Note: An <em>IPAddr</em> does not need to be resolved by
        the DNS system, so it can result in more effective apache
        performance. 

        <p><strong>See Also:</strong> <a
        href="../dns-caveats.html">DNS Issues</a></p>
        <!-- ===================== Hostname ======================= -->
      </dd>

      <dt><a id="hostname"
      name="hostname"><em>Hostname</em></a></dt>

      <dd>
        A <em>Hostname</em> is a fully qualified DNS domain name
        which can be resolved to one or more <a
        href="#ipaddr"><em>IPAddrs</em></a> via the DNS domain name
        service. It represents a logical host (in contrast to <a
        href="#domain"><em>Domain</em></a>s, see above) and must be
        resolvable to at least one <a
        href="#ipaddr"><em>IPAddr</em></a> (or often to a list of
        hosts with different <a
        href="#ipaddr"><em>IPAddr</em></a>'s).<br />
         Examples: <samp>prep.ai.mit.edu</samp>
        <samp>www.apache.org.</samp><br />
         Note: In many situations, it is more effective to specify
        an <a href="#ipaddr"><em>IPAddr</em></a> in place of a
        <em>Hostname</em> since a DNS lookup can be avoided. Name
        resolution in Apache can take a remarkable deal of time
        when the connection to the name server uses a slow PPP
        link.<br />
         Note: <em>Hostname</em> comparisons are done without
        regard to the case, and <em>Hostname</em>s are always
        assumed to be anchored in the root of the DNS tree,
        therefore two hosts <samp>WWW.MyDomain.com</samp> and
        <samp>www.mydomain.com.</samp> (note the trailing period)
        are considered equal.<br />
         

        <p><strong>See Also:</strong> <a
        href="../dns-caveats.html">DNS Issues</a></p>
      </dd>
    </dl>
    <hr />

    <h2><a id="proxydomain" name="proxydomain">ProxyDomain</a>
    directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ProxyDomain
    <em>Domain</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <em>None</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> <em>Not
    applicable</em><br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Base<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_proxy<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> ProxyDomain is
    only available in Apache 1.3 and later. 

    <p>This directive is only useful for Apache proxy servers
    within intranets. The ProxyDomain 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
    <em>Domain</em> appended will be generated.</p>

    <p>Example:</p>
<pre>
  ProxyRemote  *  http://firewall.mycompany.com:81
  NoProxy         .mycompany.com 192.168.112.0/21 
  ProxyDomain     .mycompany.com
</pre>
    <hr />

    <h2><a id="proxyvia" name="proxyvia">ProxyVia</a>
    directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> ProxyVia
    on|off|full|block<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <em>ProxyVia
    off</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> <em>Not
    applicable</em><br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Base<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_proxy<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> ProxyVia is only
    available in Apache 1.3.2 and later. 

    <p>This directive controls the use of the <samp>Via:</samp>
    HTTP header by the proxy. Its intended use is to control the
    flow of of proxy requests along a chain of proxy servers. See
    RFC2068 (HTTP/1.1) for an explanation of <samp>Via:</samp>
    header lines.</p>

    <ul>
      <li>If set to <em>off</em>, which is the default, no special
      processing is performed. If a request or reply contains a
      <samp>Via:</samp> header, it is passed through
      unchanged.</li>

      <li>If set to <em>on</em>, each request and reply will get a
      <samp>Via:</samp> header line added for the current
      host.</li>

      <li>If set to <em>full</em>, each generated <samp>Via:</samp>
      header line will additionally have the Apache server version
      shown as a <samp>Via:</samp> comment field.</li>

      <li>If set to <em>block</em>, every proxy request will have
      all its <samp>Via:</samp> header lines removed. No new
      <samp>Via:</samp> header will be generated.</li>
    </ul>
    <hr />

    <h2><a id="cacheforcecompletion"
    name="cacheforcecompletion">CacheForceCompletion</a>
    directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> CacheForceCompletion
    <em>percentage</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <em>90</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> <em>Not
    applicable</em><br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Base<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_proxy<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a>
    CacheForceCompletion is only available in Apache 1.3.1 and
    later. 

    <p>If an http transfer that is being cached is cancelled, the
    proxy module will complete the transfer to cache if more than
    the percentage specified has already been transferred.</p>

    <p>This is a percentage, and must be a number between 1 and
    100, or 0 to use the default. 100 will cause a document to be
    cached only if the transfer was allowed to complete. A number
    between 60 and 90 is recommended.</p>
    <hr />

    <h2><a id="cacheroot" name="cacheroot">CacheRoot</a>
    directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> CacheRoot
    <em>directory</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <em>None</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> <em>Not
    applicable</em><br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Base<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_proxy<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> CacheRoot is
    only available in Apache 1.1 and later. 

    <p>Sets the name of the directory to contain cache files; this
    must be writable by the httpd server. (see the <a
    href="core.html#user"><code>User</code></a> directive).<br />
     Setting <code>CacheRoot</code> enables proxy cacheing; without
    defining a <code>CacheRoot</code>, proxy functionality will be
    available if <code>ProxyRequests</code> are set to
    <code>On</code>, but no cacheing will be available.</p>
    <hr />

    <h2><a id="cachesize" name="cachesize">CacheSize</a>
    directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> CacheSize
    <em>kilobytes</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>CacheSize
    5</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> <em>Not
    applicable</em><br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Base<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_proxy<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> CacheSize is
    only available in Apache 1.1 and later. 

    <p>Sets the desired space usage of the cache, in KB (1024-byte
    units). Although usage may grow above this setting, the garbage
    collection will delete files until the usage is at or below
    this setting.<br />
     Depending on the expected proxy traffic volume and
    <code>CacheGcInterval</code>, use a value which is at least 20
    to 40 % lower than the available space.</p>
    <hr />

    <h2><a id="cachegcinterval"
    name="cachegcinterval">CacheGcInterval</a> directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> CacheGcInterval
    <em>hours</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <em>None</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> <em>Not
    applicable</em><br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Base<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_proxy<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> CacheGcinterval
    is only available in Apache 1.1 and later. 

    <p>Check the cache after the specified number of
    <em>hours</em>, and delete files if the space usage is greater
    than that set by CacheSize. Note that <em>hours</em> accepts a
    float value, you could for example use <code>CacheGcInterval
    1.5</code> to check the cache every 90 minutes. (If unset, no
    garbage collection will be performed, and the cache will grow
    indefinitely.) Note also that the larger the
    <code>CacheGcInterval</code>, the more extra space beyond the
    configured <code>CacheSize</code> will be needed for the cache
    between garbage collections.<br />
     <!-- Note that due to a design flaw, Apache
            does not automatically force a garbage collection when the available
            space on the file system where the cache resides is exhausted. -->
    </p>
    <hr />

    <h2><a id="cachemaxexpire"
    name="cachemaxexpire">CacheMaxExpire</a> directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> CacheMaxExpire
    <em>hours</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>CacheMaxExpire
    24</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> <em>Not
    applicable</em><br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Base<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_proxy<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> CacheMaxExpire
    is only available in Apache 1.1 and later. 

    <p>Specifies the maximum number of <em>hours</em> for which
    cachable HTTP documents will be retained without checking the
    origin server. Thus, documents will be out of date at most this
    number of <em>hours</em> This restriction is enforced even if
    an expiry date was supplied with the document.</p>
    <hr />

    <h2><a id="cachelastmodifiedfactor"
    name="cachelastmodifiedfactor">CacheLastModifiedFactor</a>
    directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> CacheLastModifiedFactor
    <em>factor</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a>
    <code>CacheLastModifiedFactor 0.1</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> <em>Not
    applicable</em><br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Base<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_proxy<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a>
    CacheLastModifiedFactor is only available in Apache 1.1 and
    later. 

    <p>If the origin HTTP server did not supply an expiry date for
    the document, then estimate one using the formula</p>
<pre>
  expiry-period = time-since-last-modification * <em>factor</em>
</pre>
    For example, if the document was last modified 10 hours ago,
    and <em>factor</em> is 0.1, then the expiry period will be set
    to 10*0.1 = 1 hour. 

    <p>If the expiry-period would be longer than that set by
    CacheMaxExpire, then the latter takes precedence.</p>
    <hr />

    <h2><a id="cachedirlevels"
    name="cachedirlevels">CacheDirLevels</a> directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> CacheDirLevels
    <em>levels</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>CacheDirLevels
    3</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> <em>Not
    applicable</em><br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Base<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_proxy<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> CacheDirLevels
    is only available in Apache 1.1 and later. 

    <p>CacheDirLevels sets the number of <em>levels</em> of
    subdirectories in the cache. Cached data will be saved this
    many directory levels below CacheRoot.</p>
    <hr />

    <h2><a id="cachedirlength"
    name="cachedirlength">CacheDirLength</a> directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> CacheDirLength
    <em>length</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>CacheDirLength
    1</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> <em>Not
    applicable</em><br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Base<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_proxy<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> CacheDirLength
    is only available in Apache 1.1 and later. 

    <p>CacheDirLength sets the number of characters in proxy cache
    subdirectory names.</p>
    <hr />

    <h2><a id="cachedefaultexpire"
    name="cachedefaultexpire">CacheDefaultExpire</a> directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> CacheDefaultExpire
    <em>hours</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a>
    <code>CacheDefaultExpire 1</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> <em>Not
    applicable</em><br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Base<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_proxy<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a>
    CacheDefaultExpire is only available in Apache 1.1 and later. 

    <p>If the document is fetched via a protocol that does not
    support expiry times, then use the specified number of
    <em>hours</em> as the expiry time. <a
    href="#cachemaxexpire">CacheMaxExpire</a> does
    <strong>not</strong> override this setting.</p>
    <hr />

    <h2><a id="nocache" name="nocache">NoCache</a> directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> NoCache
    *|<em>word|host|domain</em> [<em>word|host|domain</em>]
    ...<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <em>None</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config, virtual
    host<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> <em>Not
    applicable</em><br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Base<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_proxy<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> NoCache is only
    available in Apache 1.1 and later. 

    <p>The NoCache directive specifies a list of words, hosts
    and/or domains, separated by spaces. HTTP and non-passworded
    FTP documents from matched words, hosts or domains are
    <em>not</em> cached 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. Example:</p>
<pre>
  NoCache joes-garage.com some-host.co.uk bullwinkle.wotsamattau.edu
</pre>
    'bullwinkle.wotsamattau.edu' would also be matched if
    referenced by IP address. 

    <p>Note that 'wotsamattau' would also be sufficient to match
    'wotsamattau.edu'.</p>

    <p>Note also that</p>
<pre>
NoCache *
</pre>
    disables caching completely. 

    <p><!--#include virtual="footer.html" -->
    </p>
  </body>
</html>