I have a test network consisting of four servers running windows 2003 server R2 SP2. I have set up a domain which functioned correctly for about a day and a half until the other servers decided they can no longer connect to the domain controller. Ping resolves the domain controllers name to the correct ip nslookup finds the ip but can not resolve the name.

When I attempt to log on to a machine on the domain it takes around twenty minutes...