I have 3 domain controllers all do DNS and DHCP for their range. The main DC does not want to resolve names or gives me internment DNS issues.
For example if I reboot the main DC it takes forever to come up first of all and it's a fairly new machine. Second DNS works like a champ for an hour or two then goes to hell. If the DNS record is for a remote location like another office on the WAN, I can no longer ping it by name on my desktop. I have to use the IP. If I flush my DNS and register all is well for a bit again.
Another issue is the DNS seems to work fine after the DC is rebooted for people coming in on our VPN. However after the DC has been up for an hour or two you can no longer resolve things via the name when you VPN in. Restarting the DNS services does no good.
Everything works great once rebooted for a small period of time