When trying to log into a new box setup with pam_krb auth I get the following:

error guessing name of local host principal
TGTR failed verification using keytab: Hostname cannot be canonicalized

This sounds like a DNS verification error of some sort.. Assuming I am on the right track, does anyone know more specifically what it is failing to resolve (client, server, or auth server hostname, PTR lookup)?

2 Answers 2


Creating a DNS A record and PTR record for the server that was showing this error resolved the issue.


Alternately, add

  validate = false

to /etc/krb5.conf (credit: http://www.linuxforums.org/forum/red-hat-fedora-linux/183923-rhel5-6-issues-ldap-krb5-authentication.html#post877263)

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