One things don’t work it’s always good to go back to the fundamentals.
In the case discussed in this TMG Firewall Team blog post, the person who called CSS created a Server Publishing Rule for an SMTP server but the rule didn’t forward mail to the published SMTP server.
What was even worse was that this same SMTP server was also used for the outbound mail relay (yes, I know, not a good idea, but somebody has to do it that way I guess) and the outbound mail didn’t leave through the TMG firewall either.
What could cause this problem? The SMTP server used the TMG firewall as it’s default gateway, so we should be good there. The Access Rule for outbound SMTP looked good, and the Server Publishing Rule for the incoming mail looked good too.
So what could be the problem?
Check out the TMG Firewall Team’s blog post and you’ll quickly find the solution – hint: always go back to basics when troubleshooting TMG firewall problems.
DEBRA LITTLEJOHN SHINDER
MVP (Enterprise Security)