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<title>Access Control - Apache HTTP Server</title>
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<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>
<p class="apache">Apache HTTP Server Version 2.2</p>
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<a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.2</a> > <a href="./">How-To / Tutorials</a></div><div id="page-content"><div id="preamble"><h1>Access Control</h1>
<div class="toplang">
<p><span>Available Languages: </span><a href="../en/howto/access.html" title="English"> en </a></p>
</div>
<p>Access control refers to any means of controlling access to any
resource. This is separate from <a href="auth.html">authentication and authorization</a>.</p>
</div>
<div id="quickview"><ul id="toc"><li><img alt="" src="../images/down.gif" /> <a href="#related">Related Modules and Directives</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#host">Access control by host</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#env">Access control by environment variable</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#rewrite">Access control with mod_rewrite</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#moreinformation">More information</a></li>
</ul></div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="related" id="related">Related Modules and Directives</a></h2>
<p>Access control can be done by several different modules. The most
important of these is <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code>. Other modules
discussed in this document include <code class="module"><a href="../mod/mod_setenvif.html">mod_setenvif</a></code> and
<code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>.</p>
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="host" id="host">Access control by host</a></h2>
<p>
If you wish to restrict access to portions of your site based on the
host address of your visitors, this is most easily done using
<code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code>.
</p>
<p>The <code class="directive"><a href="../mod/mod_authz_host.html#allow">Allow</a></code> and
<code class="directive"><a href="../mod/mod_authz_host.html#deny">Deny</a></code> directives let
you allow and deny access based on the host name, or host
address, of the machine requesting a document. The
<code class="directive"><a href="../mod/mod_authz_host.html#order">Order</a></code> directive goes
hand-in-hand with these two, and tells Apache in which order to
apply the filters.</p>
<p>The usage of these directives is:</p>
<div class="example"><p><code>
Allow from <var>address</var>
</code></p></div>
<p>where <var>address</var> is an IP address (or a partial IP
address) or a fully qualified domain name (or a partial domain
name); you may provide multiple addresses or domain names, if
desired.</p>
<p>For example, if you have someone spamming your message
board, and you want to keep them out, you could do the
following:</p>
<div class="example"><p><code>
Deny from 10.252.46.165
</code></p></div>
<p>Visitors coming from that address will not be able to see
the content covered by this directive. If, instead, you have a
machine name, rather than an IP address, you can use that.</p>
<div class="example"><p><code>
Deny from <var>host.example.com</var>
</code></p></div>
<p>And, if you'd like to block access from an entire domain,
you can specify just part of an address or domain name:</p>
<div class="example"><p><code>
Deny from <var>192.168.205</var><br />
Deny from <var>phishers.example.com</var> <var>moreidiots.example</var><br />
Deny from ke
</code></p></div>
<p>Using <code class="directive"><a href="../mod/mod_authz_host.html#order">Order</a></code> will let you
be sure that you are actually restricting things to the group that you want
to let in, by combining a <code class="directive"><a href="../mod/mod_authz_host.html#deny">Deny</a></code> and an <code class="directive"><a href="../mod/mod_authz_host.html#allow">Allow</a></code> directive:</p>
<div class="example"><p><code>
Order deny,allow<br />
Deny from all<br />
Allow from <var>dev.example.com</var>
</code></p></div>
<p>Listing just the <code class="directive"><a href="../mod/mod_authz_host.html#allow">Allow</a></code>
directive would not do what you want, because it will let folks from that
host in, in addition to letting everyone in. What you want is to let
<em>only</em> those folks in.</p>
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="env" id="env">Access control by environment variable</a></h2>
<p>
<code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code>, in conjunction with
<code class="module"><a href="../mod/mod_setenvif.html">mod_setenvif</a></code>, can be used to restrict access to
your website based on the value of arbitrary environment variables.
This is done with the <code>Allow from env=</code> and <code>Deny
from env=</code> syntax.
</p>
<div class="example"><p><code>
SetEnvIf User-Agent BadBot GoAway=1<br />
Order allow,deny<br />
Allow from all<br />
Deny from env=GoAway
</code></p></div>
<div class="note"><h3>Warning:</h3>
<p>Access control by <code>User-Agent</code> is an unreliable technique,
since the <code>User-Agent</code> header can be set to anything at all,
at the whim of the end user.</p>
</div>
<p>
In the above example, the environment variable <code>GoAway</code>
is set to <code>1</code> if the <code>User-Agent</code> matches the
string <code>BadBot</code>. Then we deny access for any request when
this variable is set. This blocks that particular user agent from
the site.
</p>
<p>An environment variable test can be negated using the <code>=!</code>
syntax:</p>
<div class="example"><p>
Allow from env=!GoAway
</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="rewrite" id="rewrite">Access control with mod_rewrite</a></h2>
<p>The <code>[F]</code> <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> flag causes a 403 Forbidden
response to be sent. Using this, you can deny access to a resource based
on arbitrary criteria.</p>
<p>For example, if you wish to block access to a resource between 8pm
and 6am, you can do this using <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>.</p>
<div class="example"><p><code>
RewriteEngine On<br />
RewriteCond %{TIME_HOUR} >20 [OR]<br />
RewriteCond %{TIME_HOUR} <07<br />
RewriteRule ^/fridge - [F]
</code></p></div>
<p>This will return a 403 Forbidden response for any request after 8pm
or before 7am. This technique can be used for any criteria that you wish
to check. You can also redirect, or otherwise rewrite these requests, if
that approach is preferred.</p>
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="moreinformation" id="moreinformation">More information</a></h2>
<p>You should also read the documentation for
<code class="module"><a href="../mod/mod_auth_basic.html">mod_auth_basic</a></code> and <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code> which
contain some more information about how this all works.
<code class="module"><a href="../mod/mod_authn_alias.html">mod_authn_alias</a></code> can also help in simplifying certain
authentication configurations.</p>
<p>See the <a href="auth.html">Authentication and Authorization</a>
howto.</p>
</div></div>
<div class="bottomlang">
<p><span>Available Languages: </span><a href="../en/howto/access.html" title="English"> en </a></p>
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<p class="apache">Copyright 2012 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>
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