Microsoft suggests not using single label DNS names. In my recent experience, this should be more than just a suggestion.
I had to open a call to Microsoft this week because some brilliant systems integrator from Alphanumeric decided to leave off the domain suffix from the name of first Windows 2000 domain controller at Dillon Supply. It was dscdc1 instead of the required dscdc1.dillonsupply.com. This server is also one of two DNS servers for the domain. What this means is that the domain controller was unable to update it’s own entry in DNS because Microsoft Active Directory integrated DNS does not allow for single label DNS names by default.
So my options were thin. I tried the registry hack in this Microsoft Knowledgebase Article but it didn’t do much to help (in fact I couldn’t see that it did anything). When I ran netdiag -v I still received a fatal error that the domain controller was not registered with any DNS servers. Some websites suggest demoting the domain controller (dcpromo), changing the machine name to include the domain suffix, and then promoting it again. This is a risky venture because you gotta pray the replication takes place without error to another DC and since your DNS is hosed you will need the luck of the gods. Here’s an alternative: don’t do it.
My call to Microsoft payed off in the form of a .vbs file that will append the domain suffix to any machine name and correctly register the machine in DNS. I have only used it on a Windows 2000 server running SP4. I don’t know how it will work on any other OS version. If you download it run it at your own risk – I’m not responsible for what you do to your systems. All I can say is that it worked flawlessly for me. After running it netdiag showed successful DNS entries for the DC on all AD DNS servers.