mod_auth_tkt is a lightweight single-sign-on authentication module for apache, supporting versions 1.3.x, 2.0.x, and 2.2.x. It uses secure cookie-based tickets to implement a single-signon framework that works across multiple apache instances and servers.

mod_auth_tkt itself is completely repository-agnostic, as the actual authentication is done by a user-supplied CGI or script in your language of choice (examples are provided in Perl, with contrib libraries for use with python and PHP). This allows authentication against virtually any kind of user repository you can imagine (password files, ldap directories, databases, etc.)