mod_limits.html

<!DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"><head>
<meta http-equiv="content-type" content="text/html; charset=windows-1251">
<title>mod_limits - Apache HTTP Server</title>
<link href="css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet">
<link href="css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size">
<link href="css/manual-print.css" rel="stylesheet" media="print" type="text/css">
<link href="images/favicon.ico" rel="shortcut icon"></head>
<body>
<div id="page-header">
<p class="menu"><a href="/manual/en/mod/index.html"><br>
</a><a href="/manual/en/sitemap.html"></a></p>
<p class="apache">A Module for Apache Version 1.3.x and later</p>
</div>
<div id="path">
<br>
</div>
<div id="page-content">
<div id="preamble"><h1>Apache Module mod_limits</h1>
<div class="toplang">
<p><span>Available Languages: </span><a href="#" title="English">&nbsp;en&nbsp;</a></p>
</div>
<table class="module"><tbody><tr><th><a href="/manual/en/mod/module-dict.html#Description">Description:</a></th>
<td>Apache module to protect against DoS using the Range header attack
<br></td></tr>
<tr><th><a href="/manual/en/mod/module-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="/manual/en/mod/module-dict.html#ModuleIdentifier">Module&nbsp;Identifier:</a></th><td>limits_module</td></tr>
<tr><th><a href="/manual/en/mod/module-dict.html#SourceFile">Source&nbsp;File:</a></th><td>mod_limits.c</td></tr>
<tr><th><a href="/manual/en/mod/module-dict.html#Compatibility">Compatibility:</a></th><td>Version 1.3.x and later</td></tr></tbody></table>
<h3>Summary</h3>
<p><code class="module"><span style="text-decoration: underline;">mod_limits</span></code>
is aimed at protecting the web server during attacks.<br />
It provides a few, very usefull, functionalities:<br />
<ul>
  <li>Limit the maximum number of simultaneous connections</li>
  <li>Limit the maximum number of simultaneous connections per Vhost</li>
  <li>Limit the maximum number of spawned processes with the same UID</li>
  <li>Do not serve request if the load is over certain value</li>
</ul>
This module will not function unless mod_status is loaded and the "ExtendedStatus On" directive is set.

</p>
</div>
<br>


<div class="top"><a href="#page-header"><img alt="top" src="images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="limitmaxconnsperip" id="maxconnsperip">LimitMaxConnsPerIP Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Defines the maximum number of connections from a single IP.</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitMaxConnsPerIP <var>number</var> <var>(default: no limit)</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#Override">Override:</a></th><td>FileInfo</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Base</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_limits</td></tr>
<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Apache 2.x</td></tr>

</table>
    <p>This directive sets a limit of the maximum simultaneous connections to the server or to a vhost.

    <div class="example"><h3>Example</h3><p><code>
	ExtendedStatus On<br />
	<br />
	LoadModule limits_module modules/mod_limits.so<br />
	<br />
	&lt;IfModule mod_limits.c&gt;<br />
	&nbsp;&nbsp;&nbsp;LimitMaxConnsPerIP 30<br />
	&lt;/IfModule&gt;<br />
      <br />
    </code></p></div>

</div>

<div class="top"><a href="#page-header"><img alt="top" src="images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="limitmaxconnspervhost" id="maxconnspervhost">LimitMaxConnsPerVhost Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Defines the maximum number of connections from a single IP to a single Vhost.</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitMaxConnsPerVhost <var>number</var> <var>(default: no limit)</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#Override">Override:</a></th><td>FileInfo</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Base</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_limits</td></tr>
<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Apache 2.x</td></tr>

</table>
    <p>This directive sets a limit of the maximum simultaneous connections to a vhost.

    <div class="example"><h3>Example</h3><p><code>
	ExtendedStatus On<br />
	<br />
	LoadModule limits_module modules/mod_limits.so<br />
	<br />
	&lt;IfModule mod_limits.c&gt;<br />
	&nbsp;&nbsp;&nbsp;LimitMaxConnsPerVhost 30<br />
	&lt;/IfModule&gt;<br />
      <br />
    </code></p></div>

</div>

<div class="top"><a href="#page-header"><img alt="top" src="images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="limitmaxconnsperuid" id="maxconnsperuid">LimitMaxConnsPerUID Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Defines the maximum number of processes with the same UID.</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitMaxConnsPerUID <var>number</var> <var>(default: no limit)</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#Override">Override:</a></th><td>FileInfo</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Base</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_limits</td></tr>
<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Apache 2.x</td></tr>

</table>
    <p>This directive sets a limit of the maximum simultaneous processes for a single UID

    <div class="example"><h3>Example</h3><p><code>
	ExtendedStatus On<br />
	<br />
	LoadModule limits_module modules/mod_limits.so<br />
	<br />
	&lt;IfModule mod_limits.c&gt;<br />
	&nbsp;&nbsp;&nbsp;LimitMaxConnsPerUID 30<br />
	&lt;/IfModule&gt;<br />
      <br />
    </code></p></div>

</div>

<div class="top"><a href="#page-header"><img alt="top" src="images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="limitmaxloadavg" id="limitmaxloadavg">LimitMaxLoadAVG Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Defines the maximum number of connections from a single IP.</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LimitMaxLoadAVG <var>number</var> <var>(default: no limit)</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#Override">Override:</a></th><td>FileInfo</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Base</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_limits</td></tr>
<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Apache 2.x</td></tr>

</table>
    <p>This directive sets the maximum load average, above which files will not be served. 

    <div class="example"><h3>Example</h3><p><code>
	ExtendedStatus On<br />
	<br />
	LoadModule limits_module modules/mod_limits.so<br />
	<br />
	&lt;IfModule mod_limits.c&gt;<br />
	&nbsp;&nbsp;&nbsp;LimitMaxLoadAVG 10<br />
	&lt;/IfModule&gt;<br />
      <br />
    </code></p></div>

</div>

<div class="top"><a href="#page-header"><img alt="top" src="images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="checkloadinterval" id="checkloadinverval">CheckLoadInterval Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Defines the time between check of the system LoadAVG(in seconds).</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CheckLoadInterval <var>number</var> <var>(default: 5 seconds)</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#Override">Override:</a></th><td>FileInfo</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Base</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_limits</td></tr>
<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Apache 2.x</td></tr>

</table>
    <p>This directive sets the amount of time that has to pass between checks of /proc/loadavg. It is pointless to be set under 5 seconds, because the kernel updates the information at most every 5 seconds.

    <div class="example"><h3>Example</h3><p><code>
	LoadModule limits_module modules/mod_limits.so<br />
	<br />
	&lt;IfModule mod_limits.c&gt;<br />
	&nbsp;&nbsp;&nbsp;CheckLoadInterval 5<br />
	&lt;/IfModule&gt;<br />
      <br />
    </code></p></div>

</div>

<div class="top"><a href="#page-header"><img alt="top" src="images/up.gif"></a></div>

<div class="bottomlang"><p><span>Available Languages: </span><a href="#" title="English">&nbsp;en&nbsp;</a></p>
</div>
<div id="footer">
<p class="apache">Copyright 2010-2016 Marian Marinov &lt;mm@yuhu.biz&gt;.<br>
Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.
</p>
</div>
</div></body></html>