1<?xml version="1.0" encoding="ISO-8859-1"?> 2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> 3<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head><!-- 4 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX 5 This file is generated from xml source: DO NOT EDIT 6 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX 7 --> 8<title>Name-based Virtual Host Support - Apache HTTP Server</title> 9<link href="/style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" /> 10<link href="/style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" /> 11<link href="/style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" /><link rel="stylesheet" type="text/css" href="/style/css/prettify.css" /> 12<script src="/style/scripts/prettify.min.js" type="text/javascript"> 13</script> 14 15<link href="/images/favicon.ico" rel="shortcut icon" /></head> 16<body id="manual-page"><div id="page-header"> 17<p class="menu"><a href="/mod/">Modules</a> | <a href="/mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="/glossary.html">Glossary</a> | <a href="/sitemap.html">Sitemap</a></p> 18<p class="apache">Apache HTTP Server Version 2.4</p> 19<img alt="" src="/images/feather.gif" /></div> 20<div class="up"><a href="./"><img title="<-" alt="<-" src="/images/left.gif" /></a></div> 21<div id="path"> 22<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 2.4</a> > <a href="./">Virtual Hosts</a></div><div id="page-content"><div id="preamble"><h1>Name-based Virtual Host Support</h1> 23<div class="toplang"> 24<p><span>Available Languages: </span><a href="/de/vhosts/name-based.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> | 25<a href="/en/vhosts/name-based.html" title="English"> en </a> | 26<a href="/fr/vhosts/name-based.html" hreflang="fr" rel="alternate" title="Fran�ais"> fr </a> | 27<a href="/ja/vhosts/name-based.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> | 28<a href="/ko/vhosts/name-based.html" hreflang="ko" rel="alternate" title="Korean"> ko </a> | 29<a href="/tr/vhosts/name-based.html" hreflang="tr" rel="alternate" title="T�rk�e"> tr </a></p> 30</div> 31 32 <p>This document describes when and how to use name-based virtual hosts.</p> 33</div> 34<div id="quickview"><ul id="toc"><li><img alt="" src="/images/down.gif" /> <a href="#namevip">Name-based vs. IP-based Virtual Hosts</a></li> 35<li><img alt="" src="/images/down.gif" /> <a href="#alg">How the server selects the proper name-based virtual host</a></li> 36<li><img alt="" src="/images/down.gif" /> <a href="#using">Using Name-based Virtual Hosts</a></li> 37</ul><h3>See also</h3><ul class="seealso"><li><a href="ip-based.html">IP-based Virtual Host Support</a></li><li><a href="details.html">An In-Depth Discussion of Virtual Host Matching</a></li><li><a href="mass.html">Dynamically configured mass virtual hosting</a></li><li><a href="examples.html">Virtual Host examples for common setups</a></li></ul><ul class="seealso"><li><a href="#comments_section">Comments</a></li></ul></div> 38<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div> 39<div class="section"> 40<h2><a name="namevip" id="namevip">Name-based vs. IP-based Virtual Hosts</a></h2> 41 42 <p><a href="ip-based.html">IP-based virtual hosts</a> use the IP address of the connection to 43 determine the correct virtual host to serve. Therefore you need to 44 have a separate IP address for each host.</p> 45 46 <p>With name-based virtual hosting, the server relies on the client to 47 report the hostname as part of the HTTP headers. Using this technique, 48 many different hosts can share the same IP address.</p> 49 50 <p>Name-based virtual hosting is usually simpler, since you need 51 only configure your DNS server to map each hostname to the correct 52 IP address and then configure the Apache HTTP Server to recognize 53 the different hostnames. Name-based virtual hosting also eases 54 the demand for scarce IP addresses. Therefore you should use 55 name-based virtual hosting unless you are using equipment 56 that explicitly demands IP-based hosting. Historical reasons for 57 IP-based virtual hosting based on client support are no longer 58 applicable to a general-purpose web server.</p> 59 60 <p> Name-based virtual hosting builds off of the IP-based virtual host 61 selection algorithm, meaning that searches for the proper server name 62 occur only between virtual hosts that have the best IP-based address.</p> 63 64</div><div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div> 65<div class="section"> 66<h2><a name="alg" id="alg">How the server selects the proper name-based virtual host</a></h2> 67 68 <p>It is important to recognize that the first step in name-based virtual 69 host resolution is IP-based resolution. Name-based virtual host 70 resolution only chooses the most appropriate name-based virtual host 71 after narrowing down the candidates to the best IP-based match. Using a wildcard (*) 72 for the IP address in all of the VirtualHost directives makes this 73 IP-based mapping irrelevant.</p> 74 75 <p>When a request arrives, the server will find the best (most specific) matching 76 <code class="directive"><a href="/mod/core.html#virtualhost"><VirtualHost></a></code> argument based on 77 the IP address and port used by the request. If there is more than one virtual host 78 containing this best-match address and port combination, Apache will further 79 compare the <code class="directive"><a href="/mod/core.html#servername">ServerName</a></code> and <code class="directive"><a href="/mod/core.html#serveralias">ServerAlias</a></code> directives to the server name 80 present in the request.</p> 81 82 <h3><a name="defaultvhost" id="defaultvhost">The default name-based vhost for an IP and port combination </a></h3> 83 <p> If no matching ServerName or ServerAlias is found in the set of 84 virtual hosts containing the most specific matching IP address and port 85 combination, then <strong>the first listed virtual host</strong> that 86 matches that will be used.</p> 87</div><div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div> 88<div class="section"> 89<h2><a name="using" id="using">Using Name-based Virtual Hosts</a></h2> 90 91<table class="related"><tr><th>Related Modules</th><th>Related Directives</th></tr><tr><td><ul><li><code class="module"><a href="/mod/core.html">core</a></code></li></ul></td><td><ul><li><code class="directive"><a href="/mod/core.html#documentroot">DocumentRoot</a></code></li><li><code class="directive"><a href="/mod/core.html#serveralias">ServerAlias</a></code></li><li><code class="directive"><a href="/mod/core.html#servername">ServerName</a></code></li><li><code class="directive"><a href="/mod/core.html#virtualhost"><VirtualHost></a></code></li></ul></td></tr></table> 92 93 <p>The first step is to create a <code class="directive"><a href="/mod/core.html#virtualhost"><VirtualHost></a></code> block for 94 each different host that you would like to serve. Inside each <code class="directive"><a href="/mod/core.html#virtualhost"><VirtualHost></a></code> block, you will need at minimum a 95 <code class="directive"><a href="/mod/core.html#servername">ServerName</a></code> directive to designate 96 which host is served and a <code class="directive"><a href="/mod/core.html#documentroot">DocumentRoot</a></code> 97 directive to show where in the filesystem the content for that host 98 lives.</p> 99 100 <div class="note"><h3>Main host goes away</h3> 101 <p> Any request that doesn't match an existing <code class="directive"><a href="/mod/core.html#virtualhost"><VirtualHost></a></code> is handled by the global 102 server configuration, regardless of the hostname or ServerName.</p> 103 104 <p> When you add a name-based virtual host to an existing server, and 105 the virtual host arguments match preexisting IP and port combinations, 106 requests will now be handled by an explicit virtual host. In this case, 107 it's usually wise to create a <a href="#defaultvhost">default virtual host</a> 108 with a <code class="directive"><a href="/mod/core.html#servername">ServerName</a></code> matching that of 109 the base server. New domains on the same interface and port, but 110 requiring separate configurations, can then be added as subsequent (non-default) 111 virtual hosts.</p> 112 </div> 113 114 <div class="note"><h3>ServerName inheritance</h3> 115 <p> It is best to always explicitly list a <code class="directive"><a href="/mod/core.html#servername">ServerName</a></code> in every name-based virtual host.</p> 116 <p>If a <code class="directive"><a href="/mod/core.html#virtualhost">VirtualHost</a></code> doesn't specify 117 a <code class="directive"><a href="/mod/core.html#servername">ServerName</a></code>, a server name will be 118 inherited from the base server configuration. If no server name was 119 specified globally, one is detected at startup through reverse DNS resolution 120 of the first listening address. In either case, this inherited server name 121 will influenced name-based virtual host resolution, so it is best to always 122 explicitly list a <code class="directive"><a href="/mod/core.html#servername">ServerName</a></code> in every 123 name-based virtual host.</p> 124 </div> 125 126 <p>For example, suppose that you are serving the domain 127 <code>www.example.com</code> and you wish to add the virtual host 128 <code>other.example.com</code>, which points at the same IP address. 129 Then you simply add the following to <code>httpd.conf</code>:</p> 130 131 <pre class="prettyprint lang-config"><VirtualHost *:80> 132 # This first-listed virtual host is also the default for *:80 133 ServerName www.example.com 134 ServerAlias example.com 135 DocumentRoot /www/domain 136</VirtualHost> 137 138<VirtualHost *:80> 139 ServerName other.example.com 140 DocumentRoot /www/otherdomain 141</VirtualHost></pre> 142 143 144 <p>You can alternatively specify an explicit IP address in place of the 145 <code>*</code> in <code class="directive"><a href="/mod/core.html#virtualhost"><VirtualHost></a></code> directives. For example, you might want to do this 146 in order to run some name-based virtual hosts on one IP address, and either 147 IP-based, or another set of name-based virtual hosts on another address.</p> 148 149 <p>Many servers want to be accessible by more than one name. This is 150 possible with the <code class="directive"><a href="/mod/core.html#serveralias">ServerAlias</a></code> 151 directive, placed inside the <code class="directive"><a href="/mod/core.html#virtualhost"><VirtualHost></a></code> section. For example in the first <code class="directive"><a href="/mod/core.html#virtualhost"><VirtualHost></a></code> block above, the 152 <code class="directive"><a href="/mod/core.html#serveralias">ServerAlias</a></code> directive indicates that 153 the listed names are other names which people can use to see that same 154 web site:</p> 155 156 <pre class="prettyprint lang-config">ServerAlias example.com *.example.com</pre> 157 158 159 <p>then requests for all hosts in the <code>example.com</code> domain will 160 be served by the <code>www.example.com</code> virtual host. The wildcard 161 characters <code>*</code> and <code>?</code> can be used to match names. 162 Of course, you can't just make up names and place them in <code class="directive"><a href="/mod/core.html#servername">ServerName</a></code> or <code>ServerAlias</code>. You must 163 first have your DNS server properly configured to map those names to an IP 164 address associated with your server.</p> 165 166 <p>Name-based virtual hosts for the best-matching set of <code class="directive"><a href="/mod/core.html#virtualhost"><virtualhost></a></code>s are processed 167 in the order they appear in the configuration. The first matching <code class="directive"><a href="/mod/core.html#servername">ServerName</a></code> or <code class="directive"><a href="/mod/core.html#serveralias">ServerAlias</a></code> is used, with no different precedence for wildcards 168 (nor for ServerName vs. ServerAlias). </p> 169 170 <p>The complete list of names in the <code class="directive"><a href="/mod/core.html#virtualhost">VirtualHost</a></code> 171 directive are treated just like a (non wildcard) 172 <code class="directive"><a href="/mod/core.html#serveralias">ServerAlias</a></code>.</p> 173 174 <p>Finally, you can fine-tune the configuration of the virtual hosts 175 by placing other directives inside the <code class="directive"><a href="/mod/core.html#virtualhost"><VirtualHost></a></code> containers. Most directives can be 176 placed in these containers and will then change the configuration only of 177 the relevant virtual host. To find out if a particular directive is allowed, 178 check the <a href="/mod/directive-dict.html#Context">Context</a> of the 179 directive. Configuration directives set in the <em>main server context</em> 180 (outside any <code class="directive"><a href="/mod/core.html#virtualhost"><VirtualHost></a></code> 181 container) will be used only if they are not overridden by the virtual host 182 settings.</p> 183 184</div></div> 185<div class="bottomlang"> 186<p><span>Available Languages: </span><a href="/de/vhosts/name-based.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> | 187<a href="/en/vhosts/name-based.html" title="English"> en </a> | 188<a href="/fr/vhosts/name-based.html" hreflang="fr" rel="alternate" title="Fran�ais"> fr </a> | 189<a href="/ja/vhosts/name-based.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> | 190<a href="/ko/vhosts/name-based.html" hreflang="ko" rel="alternate" title="Korean"> ko </a> | 191<a href="/tr/vhosts/name-based.html" hreflang="tr" rel="alternate" title="T�rk�e"> tr </a></p> 192</div><div class="top"><a href="#page-header"><img src="/images/up.gif" alt="top" /></a></div><div class="section"><h2><a id="comments_section" name="comments_section">Comments</a></h2><div class="warning"><strong>Notice:</strong><br />This is not a Q&A section. 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