I have a tough issue. I have a existing DC that is part of a WAN, and was moved to a new office. It can no longer see the internet. The firewall (Cisco ASA-5505) was changed to use the new internet provider IP, but the server (DC) can't see past the firewall. DNS was configured on this DC years ago and has been working as it should. I have not reconfigured the Site to Site VPN connection to the other offices yet, but this shouldn't be an issue, as they have been offline before.
The internal firewall (gateway) IP address didn't change (10.0.14.4). Server IP is 10.0.14.2. I deleted the forwarders and readded. I added new ones from openDNS. I cleared cache, and restarted the DNS services. Rebooted the server. Changed the ports on the switch.
I can see the internet from the PC's when I manually enter a DNS address outside the network. ie. 184.108.40.206 or 220.127.116.11. When I use the DNS address of the server (DC) it fails. With the internal DNS address in place, I can resolve internal DNS names, but not external ones. I can ping the server using the IP and DNS name from the PC's