📄 details.html.en
字号:
<?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>An In-Depth Discussion of Virtual Host Matching - 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 2.0</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 2.0</a> > <a href="./">Virtual Hosts</a></div><div id="page-content"><div id="preamble"><h1>An In-Depth Discussion of Virtual Host Matching</h1><div class="toplang"><p><span>Available Languages: </span><a href="../en/vhosts/details.html" title="English"> en </a> |<a href="../ko/vhosts/details.html" hreflang="ko" rel="alternate" title="Korean"> ko </a></p></div> <p>The virtual host code was completely rewritten in <strong>Apache 1.3</strong>. This document attempts to explain exactly what Apache does when deciding what virtual host to serve a hit from. With the help of the new <code class="directive"><a href="../mod/core.html#namevirtualhost">NameVirtualHost</a></code> directive virtual host configuration should be a lot easier and safer than with versions prior to 1.3.</p> <p>If you just want to <cite>make it work</cite> without understanding how, here are <a href="examples.html">some examples</a>.</p></div><div id="quickview"><ul id="toc"><li><img alt="" src="../images/down.gif" /> <a href="#configparsing">Config File Parsing</a></li><li><img alt="" src="../images/down.gif" /> <a href="#hostmatching">Virtual Host Matching</a></li><li><img alt="" src="../images/down.gif" /> <a href="#tips">Tips</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="configparsing" id="configparsing">Config File Parsing</a></h2> <p>There is a <em>main_server</em> which consists of all the definitions appearing outside of <code><VirtualHost></code> sections. There are virtual servers, called <em>vhosts</em>, which are defined by <code class="directive"><a href="../mod/core.html#virtualhost"><VirtualHost></a></code> sections.</p> <p>The directives <code class="directive"><a href="../mod/mpm_common.html#listen">Listen</a></code>, <code class="directive"><a href="../mod/core.html#servername">ServerName</a></code>, <code class="directive"><a href="../mod/core.html#serverpath">ServerPath</a></code>, and <code class="directive"><a href="../mod/core.html#serveralias">ServerAlias</a></code> can appear anywhere within the definition of a server. However, each appearance overrides the previous appearance (within that server).</p> <p>The default value of the <code>Listen</code> field for main_server is 80. The main_server has no default <code>ServerPath</code>, or <code>ServerAlias</code>. The default <code>ServerName</code> is deduced from the server's IP address.</p> <p>The main_server Listen directive has two functions. One function is to determine the default network port Apache will bind to. The second function is to specify the port number which is used in absolute URIs during redirects.</p> <p>Unlike the main_server, vhost ports <em>do not</em> affect what ports Apache listens for connections on.</p> <p>Each address appearing in the <code>VirtualHost</code> directive can have an optional port. If the port is unspecified it defaults to the value of the main_server's most recent <code>Listen</code> statement. The special port <code>*</code> indicates a wildcard that matches any port. Collectively the entire set of addresses (including multiple <code>A</code> record results from DNS lookups) are called the vhost's <em>address set</em>.</p> <p>Unless a <code class="directive"><a href="../mod/core.html#namevirtualhost">NameVirtualHost</a></code> directive is used for a specific IP address the first vhost with that address is treated as an IP-based vhost. The IP address can also be the wildcard <code>*</code>.</p> <p>If name-based vhosts should be used a <code>NameVirtualHost</code> directive <em>must</em> appear with the IP address set to be used for the name-based vhosts. In other words, you must specify the IP address that holds the hostname aliases (CNAMEs) for your name-based vhosts via a <code>NameVirtualHost</code> directive in your configuration file.</p> <p>Multiple <code>NameVirtualHost</code> directives can be used each with a set of <code>VirtualHost</code> directives but only one <code>NameVirtualHost</code> directive should be used for each specific IP:port pair.</p> <p>The ordering of <code>NameVirtualHost</code> and <code>VirtualHost</code> directives is not important which makes the following two examples identical (only the order of the <code>VirtualHost</code> directives for <em>one</em> address set is important, see below):</p><table><tr><td><div class="example"><p><code> NameVirtualHost 111.22.33.44<br /> <VirtualHost 111.22.33.44><br /> # server A<br /> ...<br /> </VirtualHost><br /> <VirtualHost 111.22.33.44><br /> # server B<br /> ...<br /> </VirtualHost><br /> <br /> NameVirtualHost 111.22.33.55<br /> <VirtualHost 111.22.33.55><br /> # server C<br /> ...<br /> </VirtualHost><br /> <VirtualHost 111.22.33.55><br /> # server D<br /> ...<br /> </VirtualHost></code></p></div></td><td><div class="example"><p><code> <VirtualHost 111.22.33.44><br /> # server A<br /> </VirtualHost><br /> <VirtualHost 111.22.33.55><br /> # server C<br /> ...<br /> </VirtualHost><br /> <VirtualHost 111.22.33.44><br /> # server B<br /> ...<br /> </VirtualHost><br /> <VirtualHost 111.22.33.55><br /> # server D<br /> ...<br /> </VirtualHost><br /> <br /> NameVirtualHost 111.22.33.44<br /> NameVirtualHost 111.22.33.55<br /> <br /></code></p></div></td></tr></table> <p>(To aid the readability of your configuration you should prefer the left variant.)</p> <p>After parsing the <code>VirtualHost</code> directive, the vhost server is given a default <code>Listen</code> equal to the port assigned to the first name in its <code>VirtualHost</code> directive.</p> <p>The complete list of names in the <code>VirtualHost</code> directive are treated just like a <code>ServerAlias</code> (but are not overridden by any <code>ServerAlias</code> statement) if all names resolve to the same address set. Note that subsequent <code>Listen</code> statements for this vhost will not affect the ports assigned in the address set.</p> <p>During initialization a list for each IP address is generated and inserted into an hash table. If the IP address is used in a <code>NameVirtualHost</code> directive the list contains all name-based vhosts for the given IP address. If there are no vhosts defined for that address the <code>NameVirtualHost</code> directive is ignored and an error is logged. For an IP-based vhost the list in the hash table is empty.</p> <p>Due to a fast hashing function the overhead of hashing an IP address during a request is minimal and almost not existent. Additionally the table is optimized for IP addresses which vary in the last octet.</p> <p>For every vhost various default values are set. In particular:</p> <ol> <li>If a vhost has no <code class="directive"><a href="../mod/core.html#serveradmin">ServerAdmin</a></code>, <code class="directive"><a href="../mod/core.html#resourceconfig">ResourceConfig</a></code>, <code class="directive"><a href="../mod/core.html#accessconfig">AccessConfig</a></code>, <code class="directive"><a href="../mod/core.html#timeout">Timeout</a></code>, <code class="directive"><a href="../mod/core.html#keepalivetimeout">KeepAliveTimeout</a></code>, <code class="directive"><a href="../mod/core.html#keepalive">KeepAlive</a></code>, <code class="directive"><a href="../mod/core.html#maxkeepaliverequests">MaxKeepAliveRequests</a></code>, <code class="directive"><a href="../mod/core.html#receivebuffersize">ReceiveBufferSize</a></code>, or <code class="directive"><a href="../mod/core.html#sendbuffersize">SendBufferSize</a></code> directive then the respective value is inherited from the main_server. (That is, inherited from whatever the final setting of that value is in the main_server.)</li> <li>The "lookup defaults" that define the default directory permissions for a vhost are merged with those of the main_server. This includes any per-directory configuration information for any module.</li> <li>The per-server configs for each module from the main_server are merged into the vhost server.</li> </ol> <p>Essentially, the main_server is treated as "defaults" or a "base" on which to build each vhost. But the positioning of these main_server definitions in the config file is largely irrelevant -- the entire config of the main_server has been parsed when this final merging occurs. So even if a main_server definition appears after a vhost definition it might affect the vhost definition.</p> <p>If the main_server has no <code>ServerName</code> at this point, then the hostname of the machine that <code class="program"><a href="../programs/httpd.html">httpd</a></code>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -