Does the same issue occur? If yes there is something up with your kerb setup. If the issue does not reoccur it may have been a one time confluence of circumstances.

>Can someone tell me where I need to place the ignore_root parameter mentioned above (file and line)?

• If you create a user in AD with account name root, you can logon as root
  with its AD password.
• If you don't want AD authentication for root, you can edit
  /etc/pam.d/system-auth. On the line that starts with auth and also includes
  pam_krb5.so, add this to the end: minimum_uid=1. Authentication for root (uid=0)
  will now be done locally only.
• If you want the AD user to have the same rights as root, you can set the
  user's UID to 0 (usermod -u 0 -c username). Of course, if you have used
  minimum_uid, that won't work.
• Alternatively, use sudoers to allow users to use sudo to execute specific
  tasks as root.

Andrea
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