unqualified name resolution

This is probably a dumb question, but I'm throwing it out there anyway. OS X Clients (10.4.7 in this case, but I don't think the version matters too much) can resolve unqualified host names on our network w/o a problem. Running "ping hostname" on an OS X client resolves and works just fine. However, the same does not hold true for my OS X Servers (10.4.7 again). "ping hostname" fails, but "ping hostname.domain.com" works fine. I'm sure it's probably just some minor configuration issue on the server, but I'm uncertain exactly where. Thanks!