Red Hat 6.1 and 6.2 ship with the auth_ldap rpm which permits the Apache webserver to authenticate web users against a LDAP database. For the full details, including how to build auth_ldap if your distribtution did not ship with it, take a look at the auth_ldap documentation
While Red Hat ships with auth_ldap, it is not configured to use it by default. To enable auth_ldap, first make sure you have the RPM installed:
Next, you need to edit the apache configuration file, /etc/httpd/conf/httpd.conf. There are two sections you need to edit, first look for this section:
and append a LoadModule entry for auth_ldap
Next you need to look for this section:
and append a AddModule entry for auth_ldap
Now restart apache: /etc/rc.d/init.d/httpd restart
If apache restarted without complaints, it should now be configured for LDAP authentication. If apache did not restart properly, comment out the auth_ldap lines in httpd.conf, restart apache, and then go read the full documentation.
Here's two sample .htaccess files that I use:
Feedback & additional documentation would be more than welcome!