Checking the Install
At this point, it's a good idea to check that the install and user information are all properly configured, particularly Open Directory and single sign-on (Kerberos). I started by making sure that I could log a client onto the fileserver with a user and password from the LDAP server. Then I checked that I could get a Kerberos ticket for a user and that the ssh command-line tool could use that ticket.
If you have trouble with Kerberos, consult one of the two excellent articles on AFP458.com. If your trouble is LDAP, see my two articles at MacDevCenter.com. The Reference section at the end of this article provides links.