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<!DOCTYPE modulesynopsis SYSTEM "../style/modulesynopsis.dtd">
<?xml-stylesheet type="text/xsl" href="../style/manual.en.xsl"?>
<modulesynopsis metafile="mod_auth_ldap.xml.meta">
<name>mod_auth_ldap</name>
<description>Allows an LDAP directory to be used to store the database
for HTTP Basic authentication.</description>
<status>Experimental</status>
<sourcefile>mod_auth_ldap.c</sourcefile>
<identifier>auth_ldap_module</identifier>
<compatibility>Available in version 2.0.41 and later</compatibility>
<summary>
<p><module>mod_auth_ldap</module> supports the following features:</p>
<ul>
<li>Known to support the <a
href="http://www.openldap.org/">OpenLDAP SDK</a> (both 1.x
and 2.x), <a href="http://developer.novell.com/ndk/cldap.htm">
Novell LDAP SDK</a> and the <a
href="http://www.iplanet.com/downloads/developer/">iPlanet
(Netscape)</a> SDK.</li>
<li>Complex authorization policies can be implemented by
representing the policy with LDAP filters.</li>
<li>Support for Microsoft FrontPage allows FrontPage users to
control access to their webs, while retaining LDAP for user
authentication.</li>
<li>Uses extensive caching of LDAP operations via <a
href="mod_ldap.html">mod_ldap</a>.</li>
<li>Support for LDAP over SSL (requires the Netscape SDK) or
TLS (requires the OpenLDAP 2.x SDK or Novell LDAP SDK).</li>
</ul>
</summary>
<seealso><module>mod_ldap</module></seealso>
<section id="contents"><title>Contents</title>
<ul>
<li>
<a href="#operation">Operation</a>
<ul>
<li><a href="#authenphase">The Authentication
Phase</a></li>
<li><a href="#authorphase">The Authorization
Phase</a></li>
</ul>
</li>
<li>
<a href="#requiredirectives">The require Directives</a>
<ul>
<li><a href="#reqvaliduser">require valid-user</a></li>
<li><a href="#requser">require user</a></li>
<li><a href="#reqgroup">require group</a></li>
<li><a href="#reqdn">require dn</a></li>
</ul>
</li>
<li><a href="#examples">Examples</a></li>
<li><a href="#usingtls">Using TLS</a></li>
<li><a href="#usingssl">Using SSL</a></li>
<li>
<a href="#frontpage">Using Microsoft FrontPage with
<module>mod_auth_ldap</module></a>
<ul>
<li><a href="#howitworks">How It Works</a></li>
<li><a href="#fpcaveats">Caveats</a></li>
</ul>
</li>
</ul>
</section>
<section id="operation"><title>Operation</title>
<p>There are two phases in granting access to a user. The first
phase is authentication, in which <module>mod_auth_ldap</module>
verifies that the user's credentials are valid. This also called
the <em>search/bind</em> phase. The second phase is
authorization, in which <module>mod_auth_ldap</module> determines
if the authenticated user is allowed access to the resource in
question. This is also known as the <em>compare</em>
phase.</p>
<section id="authenphase"><title>The Authentication
Phase</title>
<p>During the authentication phase, <module>mod_auth_ldap</module>
searches for an entry in the directory that matches the username
that the HTTP client passes. If a single unique match is found,
then <module>mod_auth_ldap</module> attempts to bind to the
directory server using the DN of the entry plus the password
provided by the HTTP client. Because it does a search, then a
bind, it is often referred to as the search/bind phase. Here are
the steps taken during the search/bind phase.</p>
<ol>
<li>Generate a search filter by combining the attribute and
filter provided in the <directive module="mod_auth_ldap"
>AuthLDAPURL</directive> directive with
the username passed by the HTTP client.</li>
<li>Search the directory using the generated filter. If the
search does not return exactly one entry, deny or decline
access.</li>
<li>Fetch the distinguished name of the entry retrieved from
the search and attempt to bind to the LDAP server using the
DN and the password passed by the HTTP client. If the bind is
unsuccessful, deny or decline access.</li>
</ol>
<p>The following directives are used during the search/bind
phase</p>
<table>
<tr>
<td><directive module="mod_auth_ldap">AuthLDAPURL</directive></td>
<td>Specifies the LDAP server, the
base DN, the attribute to use in the search, as well as the
extra search filter to use.</td>
</tr>
<tr>
<td><directive module="mod_auth_ldap">AuthLDAPBindDN</directive></td>
<td>An optional DN to bind with
during the search phase.</td>
</tr>
<tr>
<td><directive
module="mod_auth_ldap">AuthLDAPBindPassword</directive></td>
<td>An optional password to bind
with during the search phase.</td>
</tr>
</table>
</section>
<section id="authorphase"><title>The Authorization
Phase</title>
<p>During the authorization phase, <module>mod_auth_ldap</module>
attempts to determine if the user is authorized to access the
resource. Many of these checks require
<module>mod_auth_ldap</module> to do a compare operation on the
LDAP server. This is why this phase is often referred to as the
compare phase. <module>mod_auth_ldap</module> accepts the
following <directive module="core">Require</directive>
directives to determine if the credentials are acceptable:</p>
<ul>
<li>Grant access if there is a <a href="#requser"><code>require
valid-user</code></a> directive.</li>
<li>Grant access if there is a <a
href="#reqgroup"><code>require user</code></a> directive, and the
username in the directive matches the username passed by the
client.</li>
<li>Grant access if there is a <a href="#reqdn"><code>require
dn</code></a> directive, and the DN in the directive matches
the DN fetched from the LDAP directory.</li>
<li>Grant access if there is a <a
href="#reqgroup"><code>require group</code></a> directive, and
the DN fetched from the LDAP directory (or the username
passed by the client) occurs in the LDAP group.</li>
<li>otherwise, deny or decline access</li>
</ul>
<p><module>mod_auth_ldap</module> uses the following directives during the
compare phase:</p>
<table>
<tr>
<td><directive module="mod_auth_ldap">AuthLDAPURL</directive> </td>
<td>The attribute specified in the
URL is used in compare operations for the <code>require
user</code> operation.</td>
</tr>
<tr>
<td><directive
module="mod_auth_ldap">AuthLDAPCompareDNOnServer</directive></td>
<td>Determines the behavior of the
<code>require dn</code> directive.</td>
</tr>
<tr>
<td><directive
module="mod_auth_ldap">AuthLDAPGroupAttribute</directive></td>
<td>Determines the attribute to
use for comparisons in the <code>require group</code>
directive.</td>
</tr>
<tr>
<td><directive
module="mod_auth_ldap">AuthLDAPGroupAttributeIsDN</directive></td>
<td>Specifies whether to use the
user DN or the username when doing comparisons for the
<code>require group</code> directive.</td>
</tr>
</table>
</section>
</section>
<section id="requiredirectives"><title>The require Directives</title>
<p>Apache's <directive module="core">Require</directive>
directives are used during the authorization phase to ensure that
a user is allowed to access a resource.</p>
<section id="reqvaliduser"><title>require
valid-user</title>
<p>If this directive exists, <module>mod_auth_ldap</module> grants
access to any user that has successfully authenticated during the
search/bind phase.</p>
</section>
<section id="requser"><title>require user</title>
<p>The <code>require user</code> directive specifies what
usernames can access the resource. Once
<module>mod_auth_ldap</module> has retrieved a unique DN from the
directory, it does an LDAP compare operation using the username
specified in the <code>require user</code> to see if that username
is part of the just-fetched LDAP entry. Multiple users can be
granted access by putting multiple usernames on the line,
separated with spaces. If a username has a space in it, then it
must be surrounded with double quotes. Multiple users can also be
granted access by using multiple <code>require user</code>
directives, with one user per line. For example, with a <directive
module="mod_auth_ldap">AuthLDAPURL</directive> of
<code>ldap://ldap/o=Airius?cn</code> (i.e., <code>cn</code> is
used for searches), the following require directives could be used
to restrict access:</p>
<example>
require user "Barbara Jenson"<br />
require user "Fred User"<br />
require user "Joe Manager"<br />
</example>
<p>Because of the way that <module>mod_auth_ldap</module> handles this
directive, Barbara Jenson could sign on as <em>Barbara
Jenson</em>, <em>Babs Jenson</em> or any other <code>cn</code> that
she has in her LDAP entry. Only the single <code>require
user</code> line is needed to support all values of the attribute
in the user's entry.</p>
<p>If the <code>uid</code> attribute was used instead of the
<code>cn</code> attribute in the URL above, the above three lines
could be condensed to</p>
<example>require user bjenson fuser jmanager</example>
</section>
<section id="reqgroup"><title>require group</title>
<p>This directive specifies an LDAP group whose members are
allowed access. It takes the distinguished name of the LDAP
group. For example, assume that the following entry existed in
the LDAP directory:</p>
<example>
dn: cn=Administrators, o=Airius<br />
objectClass: groupOfUniqueNames<br />
uniqueMember: cn=Barbara Jenson, o=Airius<br />
uniqueMember: cn=Fred User, o=Airius<br />
</example>
<p>The following directive would grant access to both Fred and
Barbara:</p>
<example>require group "cn=Administrators, o=Airius"</example>
<p>Behavior of this directive is modified by the <directive
module="mod_auth_ldap">AuthLDAPGroupAttribute</directive> and
<directive
module="mod_auth_ldap">AuthLDAPGroupAttributeIsDN</directive>
directives.</p>
</section>
<section id="reqdn"><title>require dn</title>
<p>The <code>require dn</code> directive allows the administrator
to grant access based on distinguished names. It specifies a DN
that must match for access to be granted. If the distinguished
name that was retrieved from the directory server matches the
distinguished name in the <code>require dn</code>, then
authorization is granted.</p>
<p>The following directive would grant access to a specific
DN:</p>
<example>require dn "cn=Barbara Jenson, o=Airius"</example>
<p>Behavior of this directive is modified by the <directive
module="mod_auth_ldap">AuthLDAPCompareDNOnServer</directive>
directive.</p>
</section>
</section>
<section id="examples"><title>Examples</title>
<ul>
<li>
Grant access to anyone who exists in the LDAP directory,
using their UID for searches.
<example>AuthLDAPURL "ldap://ldap1.airius.com:389/ou=People, o=Airius?uid?sub?(objectClass=*)"<br />
require valid-user
</example>
</li>
<li>
The next example is the same as above; but with the fields
that have useful defaults omitted. Also, note the use of a
redundant LDAP server.
<example>AuthLDAPURL "ldap://ldap1.airius.com ldap2.airius.com/ou=People, o=Airius"<br />
require valid-user
</example>
</li>
<li>
The next example is similar to the previous one, but is
uses the common name instead of the UID. Note that this
could be problematical if multiple people in the directory
share the same <code>cn</code>, because a search on <code>cn</code>
<strong>must</strong> return exactly one entry. That's why
this approach is not recommended: it's a better idea to
choose an attribute that is guaranteed unique in your
directory, such as <code>uid</code>.
<example>
AuthLDAPURL "ldap://ldap.airius.com/ou=People, o=Airius?cn"<br />
require valid-user
</example>
</li>
<li>
Grant access to anybody in the Administrators group. The
users must authenticate using their UID.
<example>
AuthLDAPURL "ldap://ldap.airius.com/o=Airius?uid"<br />
require group cn=Administrators, o=Airius
</example>
</li>
<li>
The next example assumes that everyone at Airius who
carries an alphanumeric pager will have an LDAP attribute
of <code>qpagePagerID</code>. The example will grant access
only to people (authenticated via their UID) who have
alphanumeric pagers:
<example>
AuthLDAPURL "ldap://ldap.airius.com/o=Airius?uid??(qpagePagerID=*)"<br />
require valid-user
</example>
</li>
<li>
<p>The next example demonstrates the power of using filters
to accomplish complicated administrative requirements.
Without filters, it would have been necessary to create a
new LDAP group and ensure that the group's members remain
synchronized with the pager users. This becomes trivial
with filters. The goal is to grant access to anyone who has
a filter, plus grant access to Joe Manager, who doesn't
have a pager, but does need to access the same
resource:</p>
<example>
AuthLDAPURL "ldap://ldap.airius.com/o=Airius?uid??(|(qpagePagerID=*)(uid=jmanager))"<br />
require valid-user
</example>
<p>This last may look confusing at first, so it helps to
evaluate what the search filter will look like based on who
connects, as shown below. The text in blue is the part that
is filled in using the attribute specified in the URL. The
text in red is the part that is filled in using the filter
specified in the URL. The text in green is filled in using
the information that is retrieved from the HTTP client. If
Fred User connects as <code>fuser</code>, the filter would look
like</p>
<example>(&(|(qpagePagerID=*)(uid=jmanager))(uid=fuser))</example>
<p>The above search will only succeed if <em>fuser</em> has a
pager. When Joe Manager connects as <em>jmanager</em>, the
filter looks like</p>
<example>(&(|(qpagePagerID=*)(uid=jmanager))(uid=jmanager))</example>
<p>The above search will succeed whether <em>jmanager</em>
has a pager or not.</p>
</li>
</ul>
</section>
<section id="usingtls"><title>Using TLS</title>
<p>To use TLS, see the <module>mod_ldap</module> directives <directive
module="mod_ldap">LDAPTrustedCA</directive> and <directive
module="mod_ldap">LDAPTrustedCAType</directive>.</p>
</section>
<section id="usingssl"><title>Using SSL</title>
<p>To use SSL, see the <module>mod_ldap</module> directives <directive
module="mod_ldap">LDAPTrustedCA</directive> and <directive
module="mod_ldap">LDAPTrustedCAType</directive>.</p>
<p>To specify a secure LDAP server, use <em>ldaps://</em> in the
<directive module="mod_auth_ldap">AuthLDAPURL</directive>
directive, instead of <em>ldap://</em>.</p>
</section>
<section id="frontpage"><title>Using Microsoft
FrontPage with mod_auth_ldap</title>
<p>Normally, FrontPage uses FrontPage-web-specific user/group
files (i.e., the <module>mod_auth</module> module) to handle all
authentication. Unfortunately, it is not possible to just
change to LDAP authentication by adding the proper directives,
because it will break the <em>Permissions</em> forms in
the FrontPage client, which attempt to modify the standard
text-based authorization files.</p>
<p>Once a FrontPage web has been created, adding LDAP
authentication to it is a matter of adding the following
directives to <em>every</em> <code>.htaccess</code> file
that gets created in the web</p>
<example><pre>
AuthLDAPURL "the url"
AuthLDAPAuthoritative off
AuthLDAPFrontPageHack on
</pre></example>
<p><directive
module="mod_auth_ldap">AuthLDAPAuthoritative</directive> must be
off to allow <module>mod_auth_ldap</module> to decline group
authentication so that Apache will fall back to file
authentication for checking group membership. This allows the
FrontPage-managed group file to be used.</p>
<section id="howitworks"><title>How It Works</title>
<p>FrontPage restricts access to a web by adding the <code>require
valid-user</code> directive to the <code>.htaccess</code>
files. If <directive
module="mod_auth_ldap">AuthLDAPFrontPageHack</directive> is not
on, the <code>require valid-user</code> directive will succeed for
any user who is valid <em>as far as LDAP is
concerned</em>. This means that anybody who has an entry in
the LDAP directory is considered a valid user, whereas FrontPage
considers only those people in the local user file to be
valid. The purpose of the hack is to force Apache to consult the
local user file (which is managed by FrontPage) - instead of LDAP
- when handling the <code>require valid-user</code> directive.</p>
<p>Once directives have been added as specified above,
FrontPage users will be able to perform all management
operations from the FrontPage client.</p>
</section>
<section id="fpcaveats"><title>Caveats</title>
<ul>
<li>When choosing the LDAP URL, the attribute to use for
authentication should be something that will also be valid
for putting into a <module>mod_auth</module> user file.
The user ID is ideal for this.</li>
<li>When adding users via FrontPage, FrontPage administrators
should choose usernames that already exist in the LDAP
directory (for obvious reasons). Also, the password that the
administrator enters into the form is ignored, since Apache
will actually be authenticating against the password in the
LDAP database, and not against the password in the local user
file. This could cause confusion for web administrators.</li>
<!-- XXX is that true? was mod_auth before the aaa change -->
<li>Apache must be compiled with <module>mod_auth</module> in order to
use FrontPage support. This is because Apache will still use
the <module>mod_auth</module> group file for determine the extent of a
user's access to the FrontPage web.</li>
<li>The directives must be put in the <code>.htaccess</code>
files. Attempting to put them inside <directive module="core"
type="section">Location</directive> or <directive module="core"
type="section">Directory</directive> directives won't work. This
is because <module>mod_auth_ldap</module> has to be able to grab
the <directive module="mod_auth">AuthUserFile</directive>
directive that is found in FrontPage <code>.htaccess</code>
files so that it knows where to look for the valid user list. If
the <module>mod_auth_ldap</module> directives aren't in the same
<code>.htaccess</code> file as the FrontPage directives, then
the hack won't work, because <module>mod_auth_ldap</module> will
never get a chance to process the <code>.htaccess</code> file,
and won't be able to find the FrontPage-managed user file.</li>
</ul>
</section>
</section>
<directivesynopsis>
<name>AuthLDAPAuthoritative</name>
<description>Prevent other authentication modules from
authenticating the user if this one fails</description>
<syntax>AuthLDAPAuthoritative on|off</syntax>
<default>AuthLDAPAuthoritative on</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>
<usage>
<p>Set to <code>off</code> if this module should let other
authentication modules attempt to authenticate the user, should
authentication with this module fail. Control is only passed on
to lower modules if there is no DN or rule that matches the
supplied user name (as passed by the client).</p>
</usage>
</directivesynopsis>
<directivesynopsis>
<name>AuthLDAPBindDN</name>
<description>Optional DN to use in binding to the LDAP server</description>
<syntax>AuthLDAPBindDN <em>distinguished-name</em></syntax>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>
<usage>
<p>An optional DN used to bind to the server when searching for
entries. If not provided, <module>mod_auth_ldap</module> will use
an anonymous bind.</p>
</usage>
</directivesynopsis>
<directivesynopsis>
<name>AuthLDAPBindPassword</name>
<description>Password used in conjuction with the bind DN</description>
<syntax>AuthLDAPBindPassword <em>password</em></syntax>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>
<usage>
<p>A bind password to use in conjunction with the bind DN. Note
that the bind password is probably sensitive data, and should be
properly protected. You should only use the <directive
module="mod_auth_ldap">AuthLDAPBindDN</directive> and <directive
module="mod_auth_ldap">AuthLDAPBindPassword</directive> if you
absolutely need them to search the directory.</p>
</usage>
</directivesynopsis>
<directivesynopsis>
<name>AuthLDAPCharsetConfig</name>
<description>Language to charset conversion configuration file</description>
<syntax>AuthLDAPCharsetConfig <em>file-path</em></syntax>
<contextlist><context>server config</context>
</contextlist>
<usage>
<p>The <directive>AuthLDAPCharsetConfig</directive> directive sets the location
of the language to charset conversion configuration file. <var>File-path</var> is relative
to the <directive module="core">ServerRoot</directive>. This file specifies
the list of language extensions to character sets.
Most administrators use the provided <code>charset.conv</code>
file, which associates common language extensions to character sets.</p>
<p>The file contains lines in the following format:</p>
<example>
<var>Language-Extension</var> <var>charset</var> [<var>Language-String</var>] ...
</example>
<p>The case of the extension does not matter. Blank lines, and lines
beginning with a hash character (<code>#</code>) are ignored.</p>
</usage>
</directivesynopsis>
<directivesynopsis>
<name>AuthLDAPCompareDNOnServer</name>
<description>Use the LDAP server to compare the DNs</description>
<syntax>AuthLDAPCompareDNOnServer on|off</syntax>
<default>AuthLDAPCompareDNOnServer on</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>
<usage>
<p>When set, <module>mod_auth_ldap</module> will use the LDAP
server to compare the DNs. This is the only foolproof way to
compare DNs. <module>mod_auth_ldap</module> will search the
directory for the DN specified with the <a
href="#reqdn"><code>require dn</code></a> directive, then,
retrieve the DN and compare it with the DN retrieved from the user
entry. If this directive is not set,
<module>mod_auth_ldap</module> simply does a string comparison. It
is possible to get false negatives with this approach, but it is
much faster. Note the <module>mod_ldap</module> cache can speed up
DN comparison in most situations.</p>
</usage>
</directivesynopsis>
<directivesynopsis>
<name>AuthLDAPDereferenceAliases</name>
<description>When will the module de-reference aliases</description>
<syntax>AuthLDAPDereferenceAliases never|searching|finding|always</syntax>
<default>AuthLDAPDereferenceAliases Always</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>
<usage>
<p>This directive specifies when <module>mod_auth_ldap</module> will
de-reference aliases during LDAP operations. The default is
<code>always</code>.</p>
</usage>
</directivesynopsis>
<directivesynopsis>
<name>AuthLDAPEnabled</name>
<description>Turn on or off LDAP authentication</description>
<syntax> AuthLDAPEnabled on|off</syntax>
<default>AuthLDAPEnabled on</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>
<usage>
<p>Set to <code>off</code> to disable
<module>mod_auth_ldap</module> in certain directories. This is
useful if you have <module>mod_auth_ldap</module> enabled at or
near the top of your tree, but want to disable it completely in
certain locations.</p>
</usage>
</directivesynopsis>
<directivesynopsis>
<name>AuthLDAPFrontPageHack</name>
<description>Allow LDAP authentication to work with MS FrontPage</description>
<syntax>AuthLDAPFrontPageHack on|off</syntax>
<default>AuthLDAPFrontPageHack off</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>
<usage>
<p>See the section on <a href="#frontpage">using Microsoft
FrontPage</a> with <module>mod_auth_ldap</module>.</p>
</usage>
</directivesynopsis>
<directivesynopsis>
<name>AuthLDAPGroupAttribute</name>
<description>LDAP attributes used to check for group membership</description>
<syntax>AuthLDAPGroupAttribute <em>attribute</em></syntax>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>
<usage>
<p>This directive specifies which LDAP attributes are used to
check for group membership. Multiple attributes can be used by
specifying this directive multiple times. If not specified,
then <module>mod_auth_ldap</module> uses the <code>member</code> and
<code>uniquemember</code> attributes.</p>
</usage>
</directivesynopsis>
<directivesynopsis>
<name>AuthLDAPGroupAttributeIsDN</name>
<description>Use the DN of the client username when checking for
group membership</description>
<syntax>AuthLDAPGroupAttributeIsDN on|off</syntax>
<default>AuthLDAPGroupAttributeIsDN on</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>
<usage>
<p>When set <code>on</code>, this directive says to use the
distinguished name of the client username when checking for group
membership. Otherwise, the username will be used. For example,
assume that the client sent the username <code>bjenson</code>,
which corresponds to the LDAP DN <code>cn=Babs Jenson,
o=Airius</code>. If this directive is set,
<module>mod_auth_ldap</module> will check if the group has
<code>cn=Babs Jenson, o=Airius</code> as a member. If this
directive is not set, then <module>mod_auth_ldap</module> will
check if the group has <code>bjenson</code> as a member.</p>
</usage>
</directivesynopsis>
<directivesynopsis>
<name>AuthLDAPRemoteUserIsDN</name>
<description>Use the DN of the client username to set the REMOTE_USER
environment variable</description>
<syntax>AuthLDAPRemoteUserIsDN on|off</syntax>
<default>AuthLDAPRemoteUserIsDN off</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>
<usage>
<p>If this directive is set to on, the value of the
<code>REMOTE_USER</code> environment variable will be set to the full
distinguished name of the authenticated user, rather than just
the username that was passed by the client. It is turned off by
default.</p>
</usage>
</directivesynopsis>
<directivesynopsis>
<name>AuthLDAPUrl</name>
<description>URL specifying the LDAP search parameters</description>
<syntax>AuthLDAPUrl <em>url</em></syntax>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>
<usage>
<p>An RFC 2255 URL which specifies the LDAP search parameters
to use. The syntax of the URL is</p>
<example>ldap://host:port/basedn?attribute?scope?filter</example>
<dl>
<dt>ldap</dt>
<dd>For regular ldap, use the
string <code>ldap</code>. For secure LDAP, use <code>ldaps</code>
instead. Secure LDAP is only available if Apache was linked
to an LDAP library with SSL support.</dd>
<dt>host:port</dt>
<dd>
<p>The name/port of the ldap server (defaults to
<code>localhost:389</code> for <code>ldap</code>, and
<code>localhost:636</code> for <code>ldaps</code>). To
specify multiple, redundant LDAP servers, just list all
servers, separated by spaces. <module>mod_auth_ldap</module>
will try connecting to each server in turn, until it makes a
successful connection.</p>
<p>Once a connection has been made to a server, that
connection remains active for the life of the
<code>httpd</code> process, or until the LDAP server goes
down.</p>
<p>If the LDAP server goes down and breaks an existing
connection, <module>mod_auth_ldap</module> will attempt to
re-connect, starting with the primary server, and trying
each redundant server in turn. Note that this is different
than a true round-robin search.</p>
</dd>
<dt>basedn</dt>
<dd>The DN of the branch of the
directory where all searches should start from. At the very
least, this must be the top of your directory tree, but
could also specify a subtree in the directory.</dd>
<dt>attribute</dt>
<dd>The attribute to search for.
Although RFC 2255 allows a comma-separated list of
attributes, only the first attribute will be used, no
matter how many are provided. If no attributes are
provided, the default is to use <code>uid</code>. It's a good
idea to choose an attribute that will be unique across all
entries in the subtree you will be using.</dd>
<dt>scope</dt>
<dd>The scope of the search. Can be either <code>one</code> or
<code>sub</code>. Note that a scope of <code>base</code> is
also supported by RFC 2255, but is not supported by this
module. If the scope is not provided, or if <code>base</code> scope
is specified, the default is to use a scope of
<code>sub</code>.</dd>
<dt>filter</dt>
<dd>A valid LDAP search filter. If
not provided, defaults to <code>(objectClass=*)</code>, which
will search for all objects in the tree. Filters are
limited to approximately 8000 characters (the definition of
<code>MAX_STRING_LEN</code> in the Apache source code). This
should be than sufficient for any application.</dd>
</dl>
<p>When doing searches, the attribute, filter and username passed
by the HTTP client are combined to create a search filter that
looks like
<code>(&(<em>filter</em>)(<em>attribute</em>=<em>username</em>))</code>.</p>
<p>For example, consider an URL of
<code>ldap://ldap.airius.com/o=Airius?cn?sub?(posixid=*)</code>. When
a client attempts to connect using a username of <code>Babs
Jenson</code>, the resulting search filter will be
<code>(&(posixid=*)(cn=Babs Jenson))</code>.</p>
<p>See above for examples of <directive
module="mod_auth_ldap">AuthLDAPURL</directive> URLs.</p>
</usage>
</directivesynopsis>
</modulesynopsis>
