Configure the /etc/pam.conf file to use PAM Kerberos first.

The following example shows how to set up PAM Kerberos authentication for console login:

login auth requisite pam_authtok_get.so.1
login auth sufficient pam_krb5.so.1
login auth required pam_dhkeys.so.1
login auth required pam_unix_cred.so.1
login auth required pam_unix_auth.so.1 use_first_pass
login auth required pam_dial_auth.so.1