I have 3 Mac OS X servers all bound to AD, all configured in the Golden Triangle setup. All 3 are completely separate from each other in terms of services, but all reside on the same internal network and are all bound to the same Active Directory domain. Two are 10.5.x (latest updates) and one is 10.6.3.
Last weekend, all 3 simultaneously stopped allowing Active Directory users access to certain services, specifically AFP & SSH. SMB still works fine on all 3. I asked the AD admin if anything changed, and he said "Yes, we made a change to user accounts to toughen up security", and suggested I use email@example.com instead of just username. This still didn't work.
I have completely removed one of my servers from AD, and re-joined, but this didn't work either. I can do kinit from command line and get a Kerberos ticket. sudo klist -ke shows all services are configured to use the correct Kerberos principles.
I have been scavenging the logs for any useful info. The AFP log just shows that I'm connecting and disconnecting. The DirectoryService.log shows stuff about misconfigured Kerberos hashes, but my research is showing that's not uncommon. /var/log/system.log isn't showing anything useful that I can see.
I'm not sure where to go from here. Any help/ideas appreciated.