I had a very odd problem today at work.

An employee couldn't connect to the file server (which is also the DC,DNS,etc). It's our main/only server(other than a print server). anyways, he was receiving a valid NIC/dns/gateway ip and could ping the server fine. Though when I tried to connect via \\server1 it timed out. I tried connecting via \\ and the same thing happened.

I looked at our DNS service on the server and noticed there wasn't a (A) Host record in the FLZ for his login. I added it and after about 5 minutes he could connect fine.

I'm not convinced this was the problem though. If it was a DNS error, shouldn't I have been able to connect via \\ ??

active directory depends very heavily upon the dns service, for logons and routine work. check your server logs and look up the dns errors on the MS site