We have an exhcnage 2007 server with Mailmarshal (for mail scanning) running on the DMZ, we use Active Directory DNS for internal
A number of users have been receiving the following message randomaly (sometimes mail will go and then it will fail again.
Could not be delivered because the domain name was unresolvable:
Unable to resolve route compayxxx.com.au (MX) - *
Our Internal DNs is pointing to our ISP DNS and also using root hints. Not sure what is going on as, I tried running a NSLOOKUP command from both DMZ and Exchange and DNS server and it resolves.... although I noticed the first time I tried it came back with nothing, tried a second time and it resolved.
We only started noticing the problem in the last 2 days (no changes that I'm aware of)