On Sun, 10 Apr 2011, Alain Péan wrote:
After further verification, it seems to be related to ticket granting. Here is what I have in /var/log/messages : su: pam_krb5[7200]: TGT failed verification using keytab and key for 'host/bardeen.lab-lpp.local@LAB-LPP.LOCAL': Cannot find ticket for requested realm
I've yet to do a full upgrade to 5.6, but I have upgraded pam_krb5 to peek at this, and it works fine for me (tested against 2003 and 2008 DCs).
Contents of your /etc/krb5.conf and the output of 'klist -ke' could be instructive.
jh