1. Install Kerberos packages:

krb5.client.rte 1.4.0.7 # Network Authentication Servi…
krb5.lic 1.4.0.7 # Network Authentication Servi…

2. Configure kerberos

/usr/krb5/sbin/config.krb5 -C -r YOURDOMAIN.COM -d yourdomain.com \
-c yourdomaincontroller.com -s yourdomaincontroller.com

3. Copy /etc/krb5/krb5.conf and /usr/lib/security/methods.cfg from a good server

4. Change the users:

mkuser registery=KRB5Afiles SYSTEM=KRB5Afiles testuser

5. Make sure the clock is sync’d correctly