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| author |   hongbotian <hongbo.tianhongbo@huawei.com> | 2015-11-30 03:10:21 -0500 |
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| committer | hongbotian <hongbo.tianhongbo@huawei.com> | 2015-11-30 03:10:21 -0500 |
| commit | c0b7206652b2852bc574694e7ba07ba1c2acdc00 (patch) | |
| tree | 5cb95cb0e19e03610525903df46279df2c3b7eb1 /rubbos/app/apache2/manual/vhosts/details.html.en | |
| parent | b6d3d6e668b793220f2d3af1bc3e828553dc3fe6 (diff) | |
delete app
Change-Id: Id4c572809969ebe89e946e88063eaed262cff3f2
Signed-off-by: hongbotian <hongbo.tianhongbo@huawei.com>
Diffstat (limited to 'rubbos/app/apache2/manual/vhosts/details.html.en')
| -rw-r--r-- | rubbos/app/apache2/manual/vhosts/details.html.en | 440 |
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diff --git a/rubbos/app/apache2/manual/vhosts/details.html.en b/rubbos/app/apache2/manual/vhosts/details.html.en deleted file mode 100644 index 14ad0dac..00000000 --- a/rubbos/app/apache2/manual/vhosts/details.html.en +++ /dev/null @@ -1,440 +0,0 @@ -<?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> | -<a href="../tr/vhosts/details.html" hreflang="tr" rel="alternate" title="Türkçe"> tr </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#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> - is running on is used instead. We will call the <em>main_server address - set</em> those IP addresses returned by a DNS lookup on the - <code>ServerName</code> of the main_server.</p> - - <p>For any undefined <code>ServerName</code> fields, a - name-based vhost defaults to the address given first in the - <code>VirtualHost</code> statement defining the vhost.</p> - - <p>Any vhost that includes the magic <code>_default_</code> - wildcard is given the same <code>ServerName</code> as the - main_server.</p> - -</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> -<div class="section"> -<h2><a name="hostmatching" id="hostmatching">Virtual Host Matching</a></h2> - - <p>The server determines which vhost to use for a request as - follows:</p> - - <h3><a name="hashtable" id="hashtable">Hash table lookup</a></h3> - - <p>When the connection is first made by a client, the IP - address to which the client connected is looked up in the - internal IP hash table.</p> - - <p>If the lookup fails (the IP address wasn't found) the - request is served from the <code>_default_</code> vhost if - there is such a vhost for the port to which the client sent the - request. If there is no matching <code>_default_</code> vhost - the request is served from the main_server.</p> - - <p>If the IP address is not found in the hash table then the - match against the port number may also result in an entry - corresponding to a <code>NameVirtualHost *</code>, which is - subsequently handled like other name-based vhosts.</p> - - <p>If the lookup succeeded (a corresponding list for the IP - address was found) the next step is to decide if we have to - deal with an IP-based or a name-base vhost.</p> - - - - <h3><a name="ipbased" id="ipbased">IP-based vhost</a></h3> - - <p>If the entry we found has an empty name list then we have - found an IP-based vhost, no further actions are performed and - the request is served from that vhost.</p> - - - - <h3><a name="namebased" id="namebased">Name-based vhost</a></h3> - - <p>If the entry corresponds to a name-based vhost the name list - contains one or more vhost structures. This list contains the - vhosts in the same order as the <code>VirtualHost</code> - directives appear in the config file.</p> - - <p>The first vhost on this list (the first vhost in the config - file with the specified IP address) has the highest priority - and catches any request to an unknown server name or a request - without a <code>Host:</code> header field.</p> - - <p>If the client provided a <code>Host:</code> header field the - list is searched for a matching vhost and the first hit on a - <code>ServerName</code> or <code>ServerAlias</code> is taken - and the request is served from that vhost. A <code>Host:</code> - header field can contain a port number, but Apache always - matches against the real port to which the client sent the - request.</p> - - <p>If the client submitted a HTTP/1.0 request without - <code>Host:</code> header field we don't know to what server - the client tried to connect and any existing - <code>ServerPath</code> is matched against the URI from the - request. The first matching path on the list is used and the - request is served from that vhost.</p> - - <p>If no matching vhost could be found the request is served - from the first vhost with a matching port number that is on the - list for the IP to which the client connected (as already - mentioned before).</p> - - - - <h3><a name="persistent" id="persistent">Persistent connections</a></h3> - - <p>The IP lookup described above is only done <em>once</em> for a - particular TCP/IP session while the name lookup is done on - <em>every</em> request during a KeepAlive/persistent - connection. In other words a client may request pages from - different name-based vhosts during a single persistent - connection.</p> - - - - <h3><a name="absoluteURI" id="absoluteURI">Absolute URI</a></h3> - - <p>If the URI from the request is an absolute URI, and its - hostname and port match the main server or one of the - configured virtual hosts <em>and</em> match the address and - port to which the client sent the request, then the - scheme/hostname/port prefix is stripped off and the remaining - relative URI is served by the corresponding main server or - virtual host. If it does not match, then the URI remains - untouched and the request is taken to be a proxy request.</p> - - -<h3><a name="observations" id="observations">Observations</a></h3> - - <ul> - <li>A name-based vhost can never interfere with an IP-base - vhost and vice versa. IP-based vhosts can only be reached - through an IP address of its own address set and never - through any other address. The same applies to name-based - vhosts, they can only be reached through an IP address of the - corresponding address set which must be defined with a - <code>NameVirtualHost</code> directive.</li> - - <li><code>ServerAlias</code> and <code>ServerPath</code> - checks are never performed for an IP-based vhost.</li> - - <li>The order of name-/IP-based, the <code>_default_</code> - vhost and the <code>NameVirtualHost</code> directive within - the config file is not important. Only the ordering of - name-based vhosts for a specific address set is significant. - The one name-based vhosts that comes first in the - configuration file has the highest priority for its - corresponding address set.</li> - - <li>For security reasons the port number given in a - <code>Host:</code> header field is never used during the - matching process. Apache always uses the real port to which - the client sent the request.</li> - - <li>If a <code>ServerPath</code> directive exists which is a - prefix of another <code>ServerPath</code> directive that - appears later in the configuration file, then the former will - always be matched and the latter will never be matched. (That - is assuming that no <code>Host:</code> header field was - available to disambiguate the two.)</li> - - <li>If two IP-based vhosts have an address in common, the - vhost appearing first in the config file is always matched. - Such a thing might happen inadvertently. The server will give - a warning in the error logfile when it detects this.</li> - - <li>A <code>_default_</code> vhost catches a request only if - there is no other vhost with a matching IP address - <em>and</em> a matching port number for the request. The - request is only caught if the port number to which the client - sent the request matches the port number of your - <code>_default_</code> vhost which is your standard - <code>Listen</code> by default. A wildcard port can be - specified (<em>i.e.</em>, <code>_default_:*</code>) to catch - requests to any available port. This also applies to - <code>NameVirtualHost *</code> vhosts.</li> - - <li>The main_server is only used to serve a request if the IP - address and port number to which the client connected is - unspecified and does not match any other vhost (including a - <code>_default_</code> vhost). In other words the main_server - only catches a request for an unspecified address/port - combination (unless there is a <code>_default_</code> vhost - which matches that port).</li> - - <li>A <code>_default_</code> vhost or the main_server is - <em>never</em> matched for a request with an unknown or - missing <code>Host:</code> header field if the client - connected to an address (and port) which is used for - name-based vhosts, <em>e.g.</em>, in a - <code>NameVirtualHost</code> directive.</li> - - <li>You should never specify DNS names in - <code>VirtualHost</code> directives because it will force - your server to rely on DNS to boot. Furthermore it poses a - security threat if you do not control the DNS for all the - domains listed. There's <a href="../dns-caveats.html">more - information</a> available on this and the next two - topics.</li> - - <li><code>ServerName</code> should always be set for each - vhost. Otherwise A DNS lookup is required for each - vhost.</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="tips" id="tips">Tips</a></h2> - - <p>In addition to the tips on the <a href="../dns-caveats.html#tips">DNS Issues</a> page, here are - some further tips:</p> - - <ul> - <li>Place all main_server definitions before any - <code>VirtualHost</code> definitions. (This is to aid the - readability of the configuration -- the post-config merging - process makes it non-obvious that definitions mixed in around - virtual hosts might affect all virtual hosts.)</li> - - <li>Group corresponding <code>NameVirtualHost</code> and - <code>VirtualHost</code> definitions in your configuration to - ensure better readability.</li> - - <li>Avoid <code>ServerPaths</code> which are prefixes of - other <code>ServerPaths</code>. If you cannot avoid this then - you have to ensure that the longer (more specific) prefix - vhost appears earlier in the configuration file than the - shorter (less specific) prefix (<em>i.e.</em>, "ServerPath - /abc" should appear after "ServerPath /abc/def").</li> - </ul> - -</div></div> -<div class="bottomlang"> -<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> | -<a href="../tr/vhosts/details.html" hreflang="tr" rel="alternate" title="Türkçe"> tr </a></p> -</div><div id="footer"> -<p class="apache">Copyright 2009 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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