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diff --git a/docs/manual/rewrite/access.html.en b/docs/manual/rewrite/access.html.en new file mode 100644 index 00000000..f13d733b --- /dev/null +++ b/docs/manual/rewrite/access.html.en @@ -0,0 +1,303 @@ +<?xml version="1.0" encoding="ISO-8859-1"?> +<!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" lang="en" xml:lang="en"><head><!-- + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + This file is generated from xml source: DO NOT EDIT + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + --> +<title>Using mod_rewrite to control access - Apache HTTP Server</title> +<link href="../style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" /> +<link href="../style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" /> +<link href="../style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" /> +<link href="../images/favicon.ico" rel="shortcut icon" /></head> +<body id="manual-page"><div id="page-header"> +<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> +<img alt="" src="../images/feather.gif" /></div> +<div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div> +<div id="path"> +<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="./">Rewrite</a></div><div id="page-content"><div id="preamble"><h1>Using mod_rewrite to control access</h1> +<div class="toplang"> +<p><span>Available Languages: </span><a href="../en/rewrite/access.html" title="English"> en </a></p> +</div> + + +<p>This document supplements the <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> +<a href="../mod/mod_rewrite.html">reference documentation</a>. It describes +how you can use <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> to control access to +various resources, and other related techniques. +This includes many examples of common uses of mod_rewrite, +including detailed descriptions of how each works.</p> + +<div class="warning">Note that many of these examples won't work unchanged in your +particular server configuration, so it's important that you understand +them, rather than merely cutting and pasting the examples into your +configuration.</div> + +</div> +<div id="quickview"><ul id="toc"><li><img alt="" src="../images/down.gif" /> <a href="#blocked-inline-images">Forbidding Image "Hotlinking"</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#blocking-of-robots">Blocking of Robots</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#host-deny">Denying Hosts in a Blacklist</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#referer-deflector">Referer-based Deflector</a></li> +</ul><h3>See also</h3><ul class="seealso"><li><a href="../mod/mod_rewrite.html">Module documentation</a></li><li><a href="intro.html">mod_rewrite introduction</a></li><li><a href="remapping.html">Redirection and remapping</a></li><li><a href="vhosts.html">Virtual hosts</a></li><li><a href="proxy.html">Proxying</a></li><li><a href="rewritemap.html">Using RewriteMap</a></li><li><a href="advanced.html">Advanced techniques and tricks</a></li><li><a href="avoid.html">When not to use mod_rewrite</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="blocked-inline-images" id="blocked-inline-images">Forbidding Image "Hotlinking"</a></h2> + + + + <dl> + <dt>Description:</dt> + + <dd> + <p>The following technique forbids the practice of other sites + including your images inline in their pages. This practice is + often referred to as "hotlinking", and results in + your bandwidth being used to serve content for someone else's + site.</p> + </dd> + + <dt>Solution:</dt> + + <dd> + <p>This technique relies on the value of the + <code>HTTP_REFERER</code> variable, which is optional. As + such, it's possible for some people to circumvent this + limitation. However, most users will experience the failed + request, which should, over time, result in the image being + removed from that other site.</p> + <p>There are several ways that you can handle this + situation.</p> + + <p>In this first example, we simply deny the request, if it didn't + initiate from a page on our site. For the purpose of this example, + we assume that our site is <code>www.example.com</code>.</p> + +<div class="example"><p><code> +RewriteCond %{HTTP_REFERER} <strong>!^$</strong><br /> +RewriteCond %{HTTP_REFERER} !www.example.com [NC]<br /> +RewriteRule <strong>\.(gif|jpg|png)$</strong> - [F,NC] +</code></p></div> + + <p>In this second example, instead of failing the request, we display + an alternate image instead.</p> + +<div class="example"><p><code> +RewriteCond %{HTTP_REFERER} <strong>!^$</strong><br /> +RewriteCond %{HTTP_REFERER} !www.example.com [NC]<br /> +RewriteRule <strong>\.(gif|jpg|png)$</strong> /images/go-away.png [R,NC] +</code></p></div> + + <p>In the third example, we redirect the request to an image on some + other site.</p> + +<div class="example"><p><code> +RewriteCond %{HTTP_REFERER} <strong>!^$</strong><br /> +RewriteCond %{HTTP_REFERER} !www.example.com [NC]<br /> +RewriteRule <strong>\.(gif|jpg|png)$</strong> http://other.example.com/image.gif [R,NC] +</code></p></div> + + <p>Of these techniques, the last two tend to be the most effective + in getting people to stop hotlinking your images, because they will + simply not see the image that they expected to see.</p> + + </dd> + + <dt>Discussion:</dt> + + <dd> + <p>If all you wish to do is deny access to the resource, rather + than redirecting that request elsewhere, this can be + accomplished without the use of mod_rewrite:</p> + + <div class="example"><p><code> + SetEnvIf Referer example\.com localreferer<br /> + <FilesMatch \.(jpg|png|gif)$><br /> + Order deny,allow<br /> + Deny from all<br /> + Allow from env=localreferer<br /> + </FilesMatch> + </code></p></div> + </dd> + </dl> + + </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="blocking-of-robots" id="blocking-of-robots">Blocking of Robots</a></h2> + + + + <dl> + <dt>Description:</dt> + + <dd> + <p> + In this recipe, we discuss how to block persistent requests from + a particular robot, or user agent.</p> + + <p>The standard for robot exclusion defines a file, + <code>/robots.txt</code> that specifies those portions of your + website where you which to exclude robots. However, some robots + do not honor these files. + </p> + + <p>Note that there are methods of accomplishing this which do + not use mod_rewrite. Note also that any technique that relies on + the clients <code>USER_AGENT</code> string can be circumvented + very easily, since that string can be changed.</p> + </dd> + + <dt>Solution:</dt> + + <dd> + <p>We use a ruleset that specifies the directory to be + protected, and the client <code>USER_AGENT</code> that + identifies the malicious or persistent robot.</p> + + <p>In this example, we are blocking a robot called + <code>NameOfBadRobot</code> from a location + <code>/secret/files</code>. You may also specify an IP address + range, if you are trying to block that user agent only from the + particular source.</p> + +<div class="example"><p><code> +RewriteCond %{HTTP_USER_AGENT} ^<strong>NameOfBadRobot</strong><br /> +RewriteCond %{REMOTE_ADDR} =<strong>123\.45\.67\.[8-9]</strong><br /> +RewriteRule ^<strong>/secret/files/</strong> - [<strong>F</strong>] +</code></p></div> + </dd> + + <dt>Discussion:</dt> + + <dd> + <p> + Rather than using mod_rewrite for this, you can accomplish the + same end using alternate means, as illustrated here: + </p> + <div class="example"><p><code> + SetEnvIfNoCase User-Agent ^NameOfBadRobot goaway<br /> + <Location /secret/files><br /> + Order allow,deny<br /> + Allow from all<br /> + Deny from env=goaway<br /> + </Location> + </code></p></div> + <p> + As noted above, this technique is trivial to circumvent, by simply + modifying the <code>USER_AGENT</code> request header. If you + are experiencing a sustained attack, you should consider blocking + it at a higher level, such as at your firewall. + </p> + + </dd> + + </dl> + + </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="host-deny" id="host-deny">Denying Hosts in a Blacklist</a></h2> + + + + <dl> + <dt>Description:</dt> + + <dd> + <p>We wish to maintain a blacklist of hosts, rather like + <code>hosts.deny</code>, and have those hosts blocked from + accessing our server.</p> + </dd> + + <dt>Solution:</dt> + + <dd> +<div class="example"><p><code> +RewriteEngine on<br /> +RewriteMap hosts-deny txt:/path/to/hosts.deny<br /> +RewriteCond ${hosts-deny:%{REMOTE_ADDR}|NOT-FOUND} !=NOT-FOUND [OR]<br /> +RewriteCond ${hosts-deny:%{REMOTE_HOST}|NOT-FOUND} !=NOT-FOUND<br /> +RewriteRule ^ - [F] +</code></p></div> + +<div class="example"><p><code> +##<br /> +## hosts.deny<br /> +##<br /> +## ATTENTION! This is a map, not a list, even when we treat it as such.<br /> +## mod_rewrite parses it for key/value pairs, so at least a<br /> +## dummy value "-" must be present for each entry.<br /> +##<br /> +<br /> +193.102.180.41 -<br /> +bsdti1.sdm.de -<br /> +192.76.162.40 -<br /> +</code></p></div> + </dd> + + <dt>Discussion:</dt> + <dd> + <p> + The second RewriteCond assumes that you have HostNameLookups turned + on, so that client IP addresses will be resolved. If that's not the + case, you should drop the second RewriteCond, and drop the + <code>[OR]</code> flag from the first RewriteCond. + </p> + </dd> + </dl> + +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="referer-deflector" id="referer-deflector">Referer-based Deflector</a></h2> + + + + <dl> + <dt>Description:</dt> + + <dd> + <p>Redirect requests based on the Referer from which the request + came, with different targets per Referer.</p> + </dd> + + <dt>Solution:</dt> + + <dd> + <p>The following ruleset uses a map file to associate each Referer + with a redirection target.</p> + +<div class="example"><p><code> +RewriteMap deflector txt:/path/to/deflector.map<br /> +<br /> +RewriteCond %{HTTP_REFERER} !=""<br /> +RewriteCond ${deflector:%{HTTP_REFERER}} =-<br /> +RewriteRule ^ %{HTTP_REFERER} [R,L]<br /> +<br /> +RewriteCond %{HTTP_REFERER} !=""<br /> +RewriteCond ${deflector:%{HTTP_REFERER}|NOT-FOUND} !=NOT-FOUND<br /> +RewriteRule ^.* ${deflector:%{HTTP_REFERER}} [R,L] +</code></p></div> + + <p>The map file lists redirection targets for each referer, or, if + we just wish to redirect back to where they came from, a "-" is + placed in the map:</p> + +<div class="example"><p><code> +##<br /> +## deflector.map<br /> +##<br /> +<br /> +http://badguys.example.com/bad/index.html -<br /> +http://badguys.example.com/bad/index2.html -<br /> +http://badguys.example.com/bad/index3.html http://somewhere.example.com/ +</code></p></div> + + </dd> + </dl> + +</div></div> +<div class="bottomlang"> +<p><span>Available Languages: </span><a href="../en/rewrite/access.html" title="English"> en </a></p> +</div><div id="footer"> +<p class="apache">Copyright 2011 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> +<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> +</body></html>
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