I am currently in the process of trying to get RHEL5 to properly authenticate to Kerberos.
I have created a test account corresponding to the Username within the Kerberos server, all attempts to switch/login to this user using the Kerberos set password fail.
If I issue a $kinit <username> it will than allow me to login to the username following Kerberos authentication however it is not automatically fetching this information, it has to be manually entered every time (the kinit).
It appears I already had all the packages needed pre-installed during the installation of RHEL5...
Results of (typed) $rpm -qa | grep krb
Initially I went to System > Administration > Authentication
Checked the pretty box named Kerberos and manually replaced the /etc/krb5.conf with an appropriate one.
This is the contents of /etc/pam.d/system-auth (unchanged by hand):
auth required pam_env.so
auth sufficient pam_unix.so nullok try_first_pass
auth requisite pam_succeed_if.so uid >= 500 quiet
auth sufficient pam_krb5.so use_first_pass
auth required pam_deny.so
account required pam_unix.so broken_shadow
account sufficient pam_succeed_if.so uid < 500 quiet
account [default=bad success=ok user_unknown=ignore] pam_krb5.so
account required pam_permit.so
password requisite pam_cracklib.so try_first_pass retry=3
password sufficient pam_unix.so md5 shadow nullok try_first_pass use_authtok
password sufficient pam_krb5.so use_authtok
password required pam_deny.so
session optional pam_keyinit.so revoke
session required pam_limits.so
session optional pam_mkhomedir.so
session [success=1 default=ignore] pam_succeed_if.so service in crond quiet use_uid
session required pam_unix.so
session optional pam_krb5.so
Unfortunality I can't find any documentation to help with this issue or perhaps I am just not aware of what to look for properly.