FreeBSD-SA-00:20.krb5 MIT Kerberos 5 is an implementation of the Kerberos 5 protocol which is available in the FreeBSD ports collection as the security/krb5 port. FreeBSD also includes separately-developed Kerberos 4 and 5 implementations from KTH, which are optionally installed as part of the base system (KTH Heimdal, the Kerberos 5 implementation, is currently considered "experimental" software).
FreeBSD-SA-00:33.kerberosIV KTH Kerberos is an implementation of the Kerberos 4 protocol which is distributed as an optional component of the base system.