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| <title>Authentication, Authorization and Access Control - Apache HTTP Server</title> |
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| <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 2.1</p> |
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| <div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div> |
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| <a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs-project/">Documentation</a> > <a href="../">Version 2.1</a> > <a href="./">How-To / Tutorials</a></div><div id="page-content"><div id="preamble"><h1>Authentication, Authorization and Access Control</h1> |
| <div class="toplang"> |
| <p><span>Available Languages: </span><a href="../en/howto/auth.html" title="English"> en </a> | |
| <a href="../ja/howto/auth.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> | |
| <a href="../ko/howto/auth.html" hreflang="ko" rel="alternate" title="Korean"> ko </a></p> |
| </div> |
| |
| <p>Authentication is any process by which you verify that |
| someone is who they claim they are. Authorization is any |
| process by which someone is allowed to be where they want to |
| go, or to have information that they want to have.</p> |
| </div> |
| <div id="quickview"><ul id="toc"><li><img alt="" src="../images/down.gif" /> <a href="#related">Related Modules and Directives</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#introduction">Introduction</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#theprerequisites">The Prerequisites</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#gettingitworking">Getting it working</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#lettingmorethanonepersonin">Letting more than one |
| person in</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#possibleproblems">Possible problems</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#whatotherneatstuffcanido">What other neat stuff can I |
| do?</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#moreinformation">More information</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="related" id="related">Related Modules and Directives</a></h2> |
| <table class="related"><tr><th>Related Modules</th><th>Related Directives</th></tr><tr><td><ul><li><code class="module"><a href="../mod/mod_auth_basic.html">mod_auth_basic</a></code></li><li><code class="module"><a href="../mod/mod_authn_file.html">mod_authn_file</a></code></li><li><code class="module"><a href="../mod/mod_authz_groupfile.html">mod_authz_groupfile</a></code></li><li><code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code></li></ul></td><td><ul><li><code class="directive"><a href="../mod/mod_authz_host.html#allow">Allow</a></code></li><li><code class="directive"><a href="../mod/mod_authz_groupfile.html#authgroupfile">AuthGroupFile</a></code></li><li><code class="directive"><a href="../mod/core.html#authname">AuthName</a></code></li><li><code class="directive"><a href="../mod/core.html#authtype">AuthType</a></code></li><li><code class="directive"><a href="../mod/mod_authn_file.html#authuserfile">AuthUserFile</a></code></li><li><code class="directive"><a href="../mod/mod_authz_host.html#deny">Deny</a></code></li><li><code class="directive"><a href="../mod/core.html#options">Options</a></code></li><li><code class="directive"><a href="../mod/core.html#require">Require</a></code></li></ul></td></tr></table> |
| </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> |
| <div class="section"> |
| <h2><a name="introduction" id="introduction">Introduction</a></h2> |
| <p>If you have information on your web site that is sensitive |
| or intended for only a small group of people, the techniques in |
| this article will help you make sure that the people that see |
| those pages are the people that you wanted to see them.</p> |
| |
| <p>This article covers the "standard" way of protecting parts |
| of your web site that most of you are going to use.</p> |
| </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> |
| <div class="section"> |
| <h2><a name="theprerequisites" id="theprerequisites">The Prerequisites</a></h2> |
| <p>The directives discussed in this article will need to go |
| either in your main server configuration file (typically in a |
| <code class="directive"><a href="../mod/core.html#directory"><Directory></a></code> section), or |
| in per-directory configuration files (<code>.htaccess</code> files).</p> |
| |
| <p>If you plan to use <code>.htaccess</code> files, you will |
| need to have a server configuration that permits putting |
| authentication directives in these files. This is done with the |
| <code class="directive"><a href="../mod/core.html#allowoverride">AllowOverride</a></code> directive, which |
| specifies which directives, if any, may be put in per-directory |
| configuration files.</p> |
| |
| <p>Since we're talking here about authentication, you will need |
| an <code class="directive"><a href="../mod/core.html#allowoverride">AllowOverride</a></code> directive like the |
| following:</p> |
| |
| <div class="example"><p><code> |
| AllowOverride AuthConfig |
| </code></p></div> |
| |
| <p>Or, if you are just going to put the directives directly in |
| your main server configuration file, you will of course need to |
| have write permission to that file.</p> |
| |
| <p>And you'll need to know a little bit about the directory |
| structure of your server, in order to know where some files are |
| kept. This should not be terribly difficult, and I'll try to |
| make this clear when we come to that point.</p> |
| </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> |
| <div class="section"> |
| <h2><a name="gettingitworking" id="gettingitworking">Getting it working</a></h2> |
| <p>Here's the basics of password protecting a directory on your |
| server.</p> |
| |
| <p>You'll need to create a password file. This file should be |
| placed somewhere not accessible from the web. This is so that |
| folks cannot download the password file. For example, if your |
| documents are served out of <code>/usr/local/apache/htdocs</code> you |
| might want to put the password file(s) in |
| <code>/usr/local/apache/passwd</code>.</p> |
| |
| <p>To create the file, use the <a href="../programs/htpasswd.html">htpasswd</a> utility that came |
| with Apache. This will be located in the <code>bin</code> directory |
| of wherever you installed Apache. To create the file, type:</p> |
| |
| <div class="example"><p><code> |
| htpasswd -c /usr/local/apache/passwd/passwords rbowen |
| </code></p></div> |
| |
| <p><code>htpasswd</code> will ask you for the password, and |
| then ask you to type it again to confirm it:</p> |
| |
| <div class="example"><p><code> |
| # htpasswd -c /usr/local/apache/passwd/passwords rbowen<br /> |
| New password: mypassword<br /> |
| Re-type new password: mypassword<br /> |
| Adding password for user rbowen |
| </code></p></div> |
| |
| <p>If <code>htpasswd</code> is not in your path, of course |
| you'll have to type the full path to the file to get it to run. |
| On my server, it's located at |
| <code>/usr/local/apache/bin/htpasswd</code></p> |
| |
| <p>Next, you'll need to configure the server to request a |
| password and tell the server which users are allowed access. |
| You can do this either by editing the <code>httpd.conf</code> |
| file or using an <code>.htaccess</code> file. For example, if |
| you wish to protect the directory |
| <code>/usr/local/apache/htdocs/secret</code>, you can use the |
| following directives, either placed in the file |
| <code>/usr/local/apache/htdocs/secret/.htaccess</code>, or |
| placed in <code>httpd.conf</code> inside a <Directory |
| /usr/local/apache/apache/htdocs/secret> section.</p> |
| |
| <div class="example"><p><code> |
| AuthType Basic<br /> |
| AuthName "Restricted Files"<br /> |
| AuthUserFile /usr/local/apache/passwd/passwords<br /> |
| Require user rbowen |
| </code></p></div> |
| |
| <p>Let's examine each of those directives individually. The <code class="directive"><a href="../mod/core.html#authtype">AuthType</a></code> directive selects |
| that method that is used to authenticate the user. The most |
| common method is <code>Basic</code>, and this is the method |
| implemented by <code class="module"><a href="../mod/mod_auth_basic.html">mod_auth_basic</a></code>. It is important to be aware, |
| however, that Basic authentication sends the password from the client to |
| the browser unencrypted. This method should therefore not be used for |
| highly sensitive data. Apache supports one other authentication method: |
| <code>AuthType Digest</code>. This method is implemented by <code class="module"><a href="../mod/mod_auth_digest.html">mod_auth_digest</a></code> and is much more secure. Only the most recent |
| versions of clients are known to support Digest authentication.</p> |
| |
| <p>The <code class="directive"><a href="../mod/core.html#authname">AuthName</a></code> directive sets |
| the <dfn>Realm</dfn> to be used in the authentication. The realm serves |
| two major functions. First, the client often presents this information to |
| the user as part of the password dialog box. Second, it is used by the |
| client to determine what password to send for a given authenticated |
| area.</p> |
| |
| <p>So, for example, once a client has authenticated in the |
| <code>"Restricted Files"</code> area, it will automatically |
| retry the same password for any area on the same server that is |
| marked with the <code>"Restricted Files"</code> Realm. |
| Therefore, you can prevent a user from being prompted more than |
| once for a password by letting multiple restricted areas share |
| the same realm. Of course, for security reasons, the client |
| will always need to ask again for the password whenever the |
| hostname of the server changes.</p> |
| |
| <p>The <code class="directive"><a href="../mod/mod_authn_file.html#authuserfile">AuthUserFile</a></code> |
| directive sets the path to the password file that we just |
| created with <code>htpasswd</code>. If you have a large number |
| of users, it can be quite slow to search through a plain text |
| file to authenticate the user on each request. Apache also has |
| the ability to store user information in fast database files. |
| The <code class="module"><a href="../mod/mod_authn_dbm.html">mod_authn_dbm</a></code> module provides the <code class="directive"><a href="../mod/mod_authn_dbm.html#authdbmuserfile">AuthDBMUserFile</a></code> directive. These |
| files can be created and manipulated with the <a href="../programs/dbmmanage.html">dbmmanage</a> program. Many |
| other types of authentication options are available from third |
| party modules in the <a href="http://modules.apache.org/">Apache Modules |
| Database</a>.</p> |
| |
| <p>Finally, the <code class="directive"><a href="../mod/core.html#require">Require</a></code> |
| directive provides the authorization part of the process by |
| setting the user that is allowed to access this region of the |
| server. In the next section, we discuss various ways to use the |
| <code class="directive"><a href="../mod/core.html#require">Require</a></code> directive.</p> |
| </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> |
| <div class="section"> |
| <h2><a name="lettingmorethanonepersonin" id="lettingmorethanonepersonin">Letting more than one |
| person in</a></h2> |
| <p>The directives above only let one person (specifically |
| someone with a username of <code>rbowen</code>) into the |
| directory. In most cases, you'll want to let more than one |
| person in. This is where the <code class="directive"><a href="../mod/mod_authz_groupfile.html#authgroupfile">AuthGroupFile</a></code> comes in.</p> |
| |
| <p>If you want to let more than one person in, you'll need to |
| create a group file that associates group names with a list of |
| users in that group. The format of this file is pretty simple, |
| and you can create it with your favorite editor. The contents |
| of the file will look like this:</p> |
| |
| <div class="example"><p><code> |
| GroupName: rbowen dpitts sungo rshersey |
| </code></p></div> |
| |
| <p>That's just a list of the members of the group in a long |
| line separated by spaces.</p> |
| |
| <p>To add a user to your already existing password file, |
| type:</p> |
| |
| <div class="example"><p><code> |
| htpasswd /usr/local/apache/passwd/passwords dpitts |
| </code></p></div> |
| |
| <p>You'll get the same response as before, but it will be |
| appended to the existing file, rather than creating a new file. |
| (It's the <code>-c</code> that makes it create a new password |
| file).</p> |
| |
| <p>Now, you need to modify your <code>.htaccess</code> file to |
| look like the following:</p> |
| |
| <div class="example"><p><code> |
| AuthType Basic<br /> |
| AuthName "By Invitation Only"<br /> |
| AuthUserFile /usr/local/apache/passwd/passwords<br /> |
| AuthGroupFile /usr/local/apache/passwd/groups<br /> |
| Require group GroupName |
| </code></p></div> |
| |
| <p>Now, anyone that is listed in the group <code>GroupName</code>, |
| and has an entry in the <code>password</code> file, will be let in, if |
| they type the correct password.</p> |
| |
| <p>There's another way to let multiple users in that is less |
| specific. Rather than creating a group file, you can just use |
| the following directive:</p> |
| |
| <div class="example"><p><code> |
| Require valid-user |
| </code></p></div> |
| |
| <p>Using that rather than the <code>Require user rbowen</code> |
| line will allow anyone in that is listed in the password file, |
| and who correctly enters their password. You can even emulate |
| the group behavior here, by just keeping a separate password |
| file for each group. The advantage of this approach is that |
| Apache only has to check one file, rather than two. The |
| disadvantage is that you have to maintain a bunch of password |
| files, and remember to reference the right one in the |
| <code class="directive"><a href="../mod/mod_authn_file.html#authuserfile">AuthUserFile</a></code> directive.</p> |
| </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> |
| <div class="section"> |
| <h2><a name="possibleproblems" id="possibleproblems">Possible problems</a></h2> |
| <p>Because of the way that Basic authentication is specified, |
| your username and password must be verified every time you |
| request a document from the server. This is even if you're |
| reloading the same page, and for every image on the page (if |
| they come from a protected directory). As you can imagine, this |
| slows things down a little. The amount that it slows things |
| down is proportional to the size of the password file, because |
| it has to open up that file, and go down the list of users |
| until it gets to your name. And it has to do this every time a |
| page is loaded.</p> |
| |
| <p>A consequence of this is that there's a practical limit to |
| how many users you can put in one password file. This limit |
| will vary depending on the performance of your particular |
| server machine, but you can expect to see slowdowns once you |
| get above a few hundred entries, and may wish to consider a |
| different authentication method at that time.</p> |
| </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> |
| <div class="section"> |
| <h2><a name="whatotherneatstuffcanido" id="whatotherneatstuffcanido">What other neat stuff can I |
| do?</a></h2> |
| <p>Authentication by username and password is only part of the |
| story. Frequently you want to let people in based on something |
| other than who they are. Something such as where they are |
| coming from.</p> |
| |
| <p>The <code class="directive"><a href="../mod/mod_authz_host.html#allow">Allow</a></code> and |
| <code class="directive"><a href="../mod/mod_authz_host.html#deny">Deny</a></code> directives let |
| you allow and deny access based on the host name, or host |
| address, of the machine requesting a document. The |
| <code class="directive"><a href="../mod/mod_authz_host.html#order">Order</a></code> directive goes |
| hand-in-hand with these two, and tells Apache in which order to |
| apply the filters.</p> |
| |
| <p>The usage of these directives is:</p> |
| |
| <div class="example"><p><code> |
| Allow from <var>address</var> |
| </code></p></div> |
| |
| <p>where <var>address</var> is an IP address (or a partial IP |
| address) or a fully qualified domain name (or a partial domain |
| name); you may provide multiple addresses or domain names, if |
| desired.</p> |
| |
| <p>For example, if you have someone spamming your message |
| board, and you want to keep them out, you could do the |
| following:</p> |
| |
| <div class="example"><p><code> |
| Deny from 205.252.46.165 |
| </code></p></div> |
| |
| <p>Visitors coming from that address will not be able to see |
| the content covered by this directive. If, instead, you have a |
| machine name, rather than an IP address, you can use that.</p> |
| |
| <div class="example"><p><code> |
| Deny from <var>host.example.com</var> |
| </code></p></div> |
| |
| <p>And, if you'd like to block access from an entire domain, |
| you can specify just part of an address or domain name:</p> |
| |
| <div class="example"><p><code> |
| Deny from <var>192.101.205</var><br /> |
| Deny from <var>cyberthugs.com</var> <var>moreidiots.com</var><br /> |
| Deny from ke |
| </code></p></div> |
| |
| <p>Using <code class="directive"><a href="../mod/mod_authz_host.html#order">Order</a></code> will let you |
| be sure that you are actually restricting things to the group that you want |
| to let in, by combining a <code class="directive"><a href="../mod/mod_authz_host.html#deny">Deny</a></code> and an <code class="directive"><a href="../mod/mod_authz_host.html#allow">Allow</a></code> directive:</p> |
| |
| <div class="example"><p><code> |
| Order deny,allow<br /> |
| Deny from all<br /> |
| Allow from <var>dev.example.com</var> |
| </code></p></div> |
| |
| <p>Listing just the <code class="directive"><a href="../mod/mod_authz_host.html#allow">Allow</a></code> |
| directive would not do what you want, because it will let folks from that |
| host in, in addition to letting everyone in. What you want is to let |
| <em>only</em> those folks in.</p> |
| </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> |
| <div class="section"> |
| <h2><a name="moreinformation" id="moreinformation">More information</a></h2> |
| <p>You should also read the documentation for |
| <code class="module"><a href="../mod/mod_auth_basic.html">mod_auth_basic</a></code> and <code class="module"><a href="../mod/mod_authz_host.html">mod_authz_host</a></code> which |
| contain some more information about how this all works.</p> |
| </div></div> |
| <div class="bottomlang"> |
| <p><span>Available Languages: </span><a href="../en/howto/auth.html" title="English"> en </a> | |
| <a href="../ja/howto/auth.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> | |
| <a href="../ko/howto/auth.html" hreflang="ko" rel="alternate" title="Korean"> ko </a></p> |
| </div><div id="footer"> |
| <p class="apache">Copyright 1999-2004 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> |
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