I'm running into a problem adding a 2008 server to our existing 2003 domain, and as I am not a Windows admin, I'm not getting the problem here. Some reading around on Technet seems to indicate that DNS devolution is the issue. Here's the setup: DNS for the entire company is hosted on a Unix server running Bind, including the service records for the Windows domain. Our toplevel is company.local, and functional domains are in subdomains, such as mgt.company.local (our management servers). Our Windows servers live mostly in office.company.local, but some of them live in .mgt.company.local and .customers.company.local. The 2003 servers all succesfully authenticate against company.local as the Windows domain. Their position in the infrastructure is set by setting the primary DNS suffix under the network settings and the computer name dialog. Trying to do the same with a brand new 2008 install throws an error though: "Changing the Primary Domain DNS name of this computer to office.company.local failed [...] The specified server cannot perform the requested operation" I tried googling, but the closest I came was the Technet article on DNS Devolution, and I can't make heads nor tails on how to apply that to my case. Addendum 2012-10-23: The problem is not joining the domain, that works, the problem is that it joins with the wrong name, as .company.local, instead of .office.company.local. So far everything works, but I'm rather afraid to run production like this, because sooner or later something is going to complain about the AD name not matching DNS.