I am hoping someone can shed some light on this one...
I have two Windows 2003 DC's - both running DNS, there are several Windows 2008 R2 and one Windows 2012 Standard server running as member servers - they are all on the same subnet.
Until today, we had no issues with resolving internet addresses via these systems.
SonicWall NSA240 is the firewall.
Earlier today I was browsing the internet, no issues at all. I accidentally configured a VM with the same IP address as the firewall (missed out a digit). This was resolved quickly. No changes were made to the firewall.
Soon after this I tried to browse a site and found that I couldn't
I bounced on to both DC's and tried to resolve internet IPs - neither worked
pinging internet addresses also fails
running tests from the firewall is successful - I can complete DNS resolution and ping tests
This led me to believe that the problem was internal - but nothing in relation to DNS has been changed.
However, not being able to ping internet IP addresses leads me to the Firewall.
DNS setup as follows on both DCs:
- DNS forwarders to 18.104.22.168 and 22.214.171.124. plus two ISP DNS servers
- Root hints are showing correctly on both systems
- Both servers are configured identically - both servers fail recursive DNS test
- Both server cannot ping external addresses (and neither can any device on network)
I have been scratching my head for a while now - all suggestions welcome!