In Microsoft DHCP it is a scope setting called domain name. Same for DHCP on Cisco routers. I was just wondering if the client is confused by not having an appropriate domain name suffix attached to its IP configuration. This can also be set manually in a Windows IP configutation by specifying "DNS Suffix" in the DNS section of the settings.

I haven't run into this issue specifically, but it does sound like a DNS issue or an issue with Active Directory, which of course depends on DNS.

Sometimes you carpe diem, sometimes your diem gets carped.