-<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
- "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
-
-<html xmlns="http://www.w3.org/1999/xhtml">
- <head>
- <meta name="generator" content="HTML Tidy, see www.w3.org" />
-
- <title>Authentication</title>
- <link rev="made" href="mailto:rbowen@rcbowen.com" />
- </head>
- <!-- Background white, links blue (unvisited), navy (visited), red (active) -->
-
- <body bgcolor="#FFFFFF" text="#000000" link="#0000FF"
- vlink="#000080" alink="#FF0000">
- <!--#include virtual="header.html" -->
-
- <h1 align="center">Authentication</h1>
- <a id="__index__" name="__index__"></a> <!-- INDEX BEGIN -->
-
-
- <ul>
- <li><a href="#introduction">Introduction</a></li>
-
- <li><a href="#theprerequisites">The prerequisites</a></li>
-
- <li><a href="#gettingitworking">Getting it working</a></li>
-
- <li><a href="#lettingmorethanonepersonin">Letting more
- than one person in</a></li>
-
- <li><a href="#possibleproblems">Possible problems</a></li>
-
- <li><a href="#whatotherneatstuffcanido">What other neat
- stuff can I do?</a></li>
-
- <li><a href="#moreinformation">More information</a></li>
- </ul>
- <!-- INDEX END -->
- <hr />
-
- <table border="1">
- <tr>
- <td valign="top"><strong>Related Modules</strong><br />
- <br />
- <a href="../mod/mod_auth.html">mod_auth</a><br />
- <a href="../mod/mod_access.html">mod_access</a><br />
- </td>
-
- <td valign="top"><strong>Related Directives</strong><br />
- <br />
- <a href="../mod/mod_access.html#allow">Allow</a><br />
- <a
- href="../mod/mod_auth.html#authgroupfile">AuthGroupFile</a><br />
- <a href="../mod/core.html#authname">AuthName</a><br />
- <a href="../mod/core.html#authtype">AuthType</a><br />
- <a
- href="../mod/mod_auth.html#authuserfile">AuthUserFile</a><br />
- <a href="../mod/mod_access.html#deny">Deny</a><br />
- <a href="../mod/core.html#options">Options</a><br />
- <a href="../mod/core.html#require">Require</a><br />
- </td>
- </tr>
- </table>
-
- <h1><a id="authentication"
- name="authentication">Authentication</a></h1>
-
+<?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>Authentication, Authorization and Access Control - 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 2.1</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-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>
<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>
-
- <h2><a id="introduction"
- name="introduction">Introduction</a></h2>
-
+</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_file.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
<p>This article covers the "standard" way of protecting parts
of your web site that most of you are going to use.</p>
-
- <h2><a id="theprerequisites" name="theprerequisites">The
- prerequisites</a></h2>
-
+</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
- <Directory> section), or in per-directory configuration
- files (<code>.htaccess</code> files).</p>
+ <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><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>
+ <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>AllowOverride</code> directive like the following:</p>
-<pre>
- AllowOverride AuthConfig
-</pre>
+ 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
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>
-
- <h2><a id="gettingitworking"
- name="gettingitworking">Getting it working</a></h2>
-
+</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>
+ 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
+ <p>To create the file, use the <a href="../programs/htpasswd.html">htpasswd</a> utility that came
with Apache. This be located in the <code>bin</code> directory
of wherever you installed Apache. To create the file, type:</p>
-<pre>
- htpasswd -c /usr/local/apache/passwd/passwords rbowen
-</pre>
+
+ <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>
-<pre>
- # htpasswd -c /usr/local/apache/passwd/passwords rbowen
- New password: mypassword
- Re-type new password: mypassword
- Adding password for user rbowen
-</pre>
+
+ <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.
<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 httpd.conf inside a <Directory
+ placed in <code>httpd.conf</code> inside a <Directory
/usr/local/apache/apache/htdocs/secret> section.</p>
-<pre>
- AuthType Basic
- AuthName "Restricted Files"
- AuthUserFile /usr/local/apache/passwd/passwords
- require user rbowen
-</pre>
-
- <p>Let's examine each of those directives individually. The <a
- href="../mod/core.html#authtype">AuthType</a> directive selects
+
+ <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 <a href="../mod/mod_auth.html">mod_auth</a>. 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 <a
- href="../mod/mod_auth_digest.html">mod_auth_digest</a> and is
- much more secure. Only the most recent versions of clients are
- known to support Digest authentication.</p>
-
- <p>The <a href="../mod/core.html#authname">AuthName</a>
- directive sets the <em>Realm</em> 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.
- So, for example, once a client has authenticated in the
+ 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.
will always need to ask again for the password whenever the
hostname of the server changes.</p>
- <p>The <a
- href="../mod/mod_auth.html#authuserfile">AuthUserFile</a>
+ <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 <a href="../mod/mod_auth_dbm.html">mod_auth_dbm</a> module
- provides the <a
- href="../mod/mod_auth_dbm.html#authdbmuserfile">AuthDBMUserFile</a>
- directive. These files can be created and
- manipulated with the <a
- href="../programs/dbmmanage.html">dbmmanage</a> program. Many
+ 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
+ party modules in the <a href="http://modules.apache.org/">Apache Modules
Database</a>.</p>
- <p>Finally, the <a href="../mod/core.html#require">require</a>
+ <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>require</code> directive.</p>
-
- <h2><a id="lettingmorethanonepersonin"
- name="lettingmorethanonepersonin">Letting more than one
- person in</a></h2>
-
+ <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 <a
- href="../mod/mod_auth.html#authgroupfile">AuthGroupFile</a>
- comes in.</p>
+ 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>
-<pre>
- GroupName: rbowen dpitts sungo rshersey
-</pre>
+
+ <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>
-<pre>
- htpasswd /usr/local/apache/passwd/password dpitts
-</pre>
+
+ <div class="example"><p><code>
+ htpasswd /usr/local/apache/passwd/password 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.
<p>Now, you need to modify your <code>.htaccess</code> file to
look like the following:</p>
-<pre>
- AuthType Basic
- AuthName "By Invitation Only"
- AuthUserFile /usr/local/apache/passwd/passwords
- AuthGroupFile /usr/local/apache/passwd/groups
- require group GroupName
-</pre>
-
- <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>
+
+ <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>
-<pre>
- require valid-user
-</pre>
- <p>Using that rather than the <code>require user rbowen</code>
+ <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 th right one in the
- <code>AuthUserFile</code> directive.</p>
-
- <h2><a id="possibleproblems" name="possibleproblems">Possible
- problems</a></h2>
-
+ 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
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>
-
- <h2><a id="whatotherneatstuffcanido"
- name="whatotherneatstuffcanido">What other neat stuff can
- I do?</a></h2>
-
+</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>allow</code> and <code>deny</code> directives let
+ <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>order</code> directive goes hand-in-hand with these two,
- and tells Apache in which order to apply the filters.</p>
+ <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>
-<pre>
- allow from address
-</pre>
- <p>where <em>address</em> is an IP address (or a partial IP
+ <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>
-<pre>
- deny from 205.252.46.165
-</pre>
+
+ <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>
-<pre>
- deny from host.example.com
-</pre>
+
+ <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>
-<pre>
- deny from 192.101.205
- deny from cyberthugs.com moreidiots.com
- deny from ke
-</pre>
-
- <p>Using <code>order</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>deny</code> and an <code>allow</code>
- directive:</p>
-<pre>
- order deny,allow
- deny from all
- allow from dev.example.com
-</pre>
-
- <p>Listing just the <code>allow</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>
- <h2><a id="moreinformation" name="moreinformation">More
- information</a></h2>
-
- <p>You should also read the documentation for <code><a
- href="../mod/mod_auth.html">mod_auth</a></code> and <code><a
- href="../mod/mod_access.html">mod_access</a></code> which
+ <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>
- </body>
-</html>
-
+</div></div>
+<div id="footer">
+<p class="apache">Maintained by the <a href="http://httpd.apache.org/docs-project/">Apache HTTP Server Documentation Project</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>
\ No newline at end of file
--- /dev/null
+<?xml version='1.0' encoding='UTF-8' ?>
+<!DOCTYPE manualpage SYSTEM "../style/manualpage.dtd">
+<?xml-stylesheet type="text/xsl" href="../style/manual.en.xsl"?>
+
+<manualpage>
+<relativepath href=".." />
+<parentdocument href="./">How-To / Tutorials</parentdocument>
+
+<title>Authentication, Authorization and Access Control</title>
+
+<summary>
+ <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>
+</summary>
+
+<section id="related"><title>Related Modules and Directives</title>
+ <related>
+ <modulelist>
+ <module>mod_auth_basic</module>
+ <module>mod_authn_file</module>
+ <module>mod_authz_groupfile</module>
+ <module>mod_authz_host</module>
+ </modulelist>
+
+ <directivelist>
+ <directive module="mod_authz_host">Allow</directive>
+ <directive module="mod_authz_groupfile">AuthGroupFile</directive>
+ <directive module="core">AuthName</directive>
+ <directive module="core">AuthType</directive>
+ <directive module="mod_authn_file">AuthUserFile</directive>
+ <directive module="mod_authz_file">Deny</directive>
+ <directive module="core">Options</directive>
+ <directive module="core">Require</directive>
+ </directivelist>
+ </related>
+</section>
+
+<section id="introduction"><title>Introduction</title>
+ <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>
+</section>
+
+<section id="theprerequisites"><title>The Prerequisites</title>
+ <p>The directives discussed in this article will need to go
+ either in your main server configuration file (typically in a
+ <directive module="core" type="section">Directory</directive> 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
+ <directive module="core">AllowOverride</directive> 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 <directive module="core">AllowOverride</directive> directive like the
+ following:</p>
+
+ <example>
+ AllowOverride AuthConfig
+ </example>
+
+ <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>
+</section>
+
+<section id="gettingitworking"><title>Getting it working</title>
+ <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 be located in the <code>bin</code> directory
+ of wherever you installed Apache. To create the file, type:</p>
+
+ <example>
+ htpasswd -c /usr/local/apache/passwd/passwords rbowen
+ </example>
+
+ <p><code>htpasswd</code> will ask you for the password, and
+ then ask you to type it again to confirm it:</p>
+
+ <example>
+ # htpasswd -c /usr/local/apache/passwd/passwords rbowen<br />
+ New password: mypassword<br />
+ Re-type new password: mypassword<br />
+ Adding password for user rbowen
+ </example>
+
+ <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>
+
+ <example>
+ AuthType Basic<br />
+ AuthName "Restricted Files"<br />
+ AuthUserFile /usr/local/apache/passwd/passwords<br />
+ Require user rbowen
+ </example>
+
+ <p>Let's examine each of those directives individually. The <directive
+ module="core">AuthType</directive> 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 <module>mod_auth_basic</module>. 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 <module
+ >mod_auth_digest</module> and is much more secure. Only the most recent
+ versions of clients are known to support Digest authentication.</p>
+
+ <p>The <directive module="core">AuthName</directive> 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 <directive module="mod_authn_file">AuthUserFile</directive>
+ 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 <module>mod_authn_dbm</module> module provides the <directive
+ module="mod_authn_dbm">AuthDBMUserFile</directive> 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 <directive module="core">Require</directive>
+ 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
+ <directive module="core">Require</directive> directive.</p>
+</section>
+
+<section id="lettingmorethanonepersonin"><title>Letting more than one
+person in</title>
+ <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 <directive module="mod_authz_groupfile"
+ >AuthGroupFile</directive> 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>
+
+ <example>
+ GroupName: rbowen dpitts sungo rshersey
+ </example>
+
+ <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>
+
+ <example>
+ htpasswd /usr/local/apache/passwd/password dpitts
+ </example>
+
+ <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>
+
+ <example>
+ 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
+ </example>
+
+ <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>
+
+ <example>
+ Require valid-user
+ </example>
+
+ <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
+ <directive module="mod_authn_file">AuthUserFile</directive> directive.</p>
+</section>
+
+<section id="possibleproblems"><title>Possible problems</title>
+ <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>
+</section>
+
+<section id="whatotherneatstuffcanido"><title>What other neat stuff can I
+do?</title>
+ <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 <directive module="mod_authz_host">Allow</directive> and
+ <directive module="mod_authz_host">Deny</directive> directives let
+ you allow and deny access based on the host name, or host
+ address, of the machine requesting a document. The
+ <directive module="mod_authz_host">Order</directive> 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>
+
+ <example>
+ Allow from <var>address</var>
+ </example>
+
+ <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>
+
+ <example>
+ Deny from 205.252.46.165
+ </example>
+
+ <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>
+
+ <example>
+ Deny from <var>host.example.com</var>
+ </example>
+
+ <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>
+
+ <example>
+ Deny from <var>192.101.205</var><br />
+ Deny from <var>cyberthugs.com</var> <var>moreidiots.com</var><br />
+ Deny from ke
+ </example>
+
+ <p>Using <directive module="mod_authz_host">Order</directive> will let you
+ be sure that you are actually restricting things to the group that you want
+ to let in, by combining a <directive
+ module="mod_authz_host">Deny</directive> and an <directive
+ module="mod_authz_host">Allow</directive> directive:</p>
+
+ <example>
+ Order deny,allow<br />
+ Deny from all<br />
+ Allow from <var>dev.example.com</var>
+ </example>
+
+ <p>Listing just the <directive module="mod_authz_host">Allow</directive>
+ 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>
+</section>
+
+<section id="moreinformation"><title>More information</title>
+ <p>You should also read the documentation for
+ <module>mod_auth_basic</module> and <module>mod_authz_host</module> which
+ contain some more information about how this all works.</p>
+</section>
+
+</manualpage>
+
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