Users are complaining internet connection is sporadic. Recently our ISP has changed DNS address so I starder my troubleshooting from there.
A little about our setup:
DNS Server is behind 2 firewalls.
DNS and ROUTER settings on the server point DNS to the internel firewall. DNS and router point to the external firewall.
DNS on DHCP is set to DNS server.
Confused yet?
If I do I NSLOOKUP on the external firewall it resolves the names at first attempt. The internal firewall doesn’t have good diagnostic tools so I can’t test it from there.
When I try to do a NSLOOKUP from the server, it resolves the names only after 3 or 4 attempts.
2 other things I have noticed are that when i do the NSLOOKUP, the resonse list the server as UNKNOWN and the resolution as non-authoritative.
Any suggestions?