I have just deployed SBS 2008 Standard and am able to do DNS Queries against the internal DNS Server, however, none of the clients are able to collect a response.
I have checked the Firewall configuration, and DNS is allowed through, and I checked the DNS Configurations as best I could.
I can't test with domain-joined PC's as this is a new deploy and I can't access http://connect.
Other services work, I set up remote Workplace access and tested it and RDP earlier from a remote location. Also, Exchange is able to send / receive mail.
Best Answer
Try restarting the DNS Server or just flushing the DNS cache. I have one 2008 server where after a few days it stops resolving any but local domain names. Just clearing the cache immediately fixes it. I still haven't worked out what is causing it.
JR
PS on rereading your question, do you mean the clients can't resolve any names, even internal ones?
Re alxconn's comment: first thanks, you've answered my question about DNS that I hadn't even asked yet! If anyone else finds their W2k8 DNS stops resolving external domains see http://support.microsoft.com/kb/968372.
Back to your question: the obvious first step is to turn off the firewall. If that still doesn't fix it download the network monitor v3.3 from www.microsoft.com/downloads and sniff a DNS query from a client to see what the server receives and what it replies. The DNS query protocol is pretty straightforward. Have you tried using nslookup and explicitely setting the DNS server using "server "?