Our environment is Exchange 2007<o:p></o:p>
We are getting external messages bounce back to users with #554 5.4.4
SMTPSEND.DNS.NonExistentDomain; nonexistent domain ##, external mail does go
out for a few minutes after the transport service is restarted but then starts
failing with users receiving #554 5.4.4 SMTPSEND.DNS.NonExistentDomain;
nonexistent domain ##
Exchange is configured with specified external DNS server, I have tested looking up the
mx records for some of the domains that have failed and all is ok with DNS, so
this does not look to be the issue. I am a little confused that mail does go
out for anything between 30 seconds and up to 6 minutes after the transport
service is restarted. I would be grateful if anyone could assist me please?
Jason Spencer