kerberos

Kerberos authentication allows your computer to log into certain services automatically without you having to enter (and re-enter) your password (it's a SSO—single sign-on—service). Kerberos v5 is baked into Windows and Internet Explorer and works great with many LDAP-enabled services (for example, Drupal's LDAP module allows includes a submodule for SSO support).

Kerberos is built into Mac OS X as well, but isn't as simple to use and configure with Chrome and FireFox as it is with Explorer on a Windows workstation. You need to do two things before you can use Kerberos for authentication in Chrome/FireFox:

Many businesses and organizations use Active Directory or other LDAP-based authentication systems, and many web applications (like Drupal) can easily integrate with them for authentication and user account provisioning.

The Kerberos Module for Apache allows users to be automatically logged into your web application, by passing through their credentials behind the scenes. This makes for a seamless user experience—the user never needs to log into your web application if the user is authenticated on his local machine.

A standard configuration for Kerberos authentication inside your Apache configuration file looks like: