Date Added: Mar 2013
Kerberos is a network authentication protocol used in client-server applications. There are two versions of Kerberos currently in use, version 4 and 5. Kerberos versions 1 through 3 were internal development versions and never released. Kerberos version 4 has a number of known weaknesses and should no long be used. There are several popular Kerberos version5 distributions today, including MIT Kerberos, Heimdal Kerberos, Sun Enterprise Authentication Mechanism (SEAM), and the Kerberos implementation in Microsoft Active Directory. MIT and Heimdal Kerberos are freely distributed in public domains.