Preventing sending SMTP to specific Outbound domains

[robhardman]

Hi

I'm trying to prevent users on my SBS2003 network from sending mail to a specific external domain - but I don't seem to be having much success with my SMTP connectors.

This is my set up:

One SMTP virutal server, forwarding to smart host.
Three SMTP connectors:
one to cover the internal domain, which is set to allow by default (cost 1)
one to cover * (cost 100) which is set allow by default except a couple of specific users
a "banned domains" connector, which is configured with the address space example.com (cost 1) and set to reject messages by default.

I have then attempt to send mail to the banned domain. Instead of getting an NDR, the mail succeeds. Users banned from sending to * work exactly as expected, so what am I doing wrong? Is it because for me, the mail is using the * connector after the banned connector fails?

Thanks for your help!

 

[anawrocki]

Any easy way to do this would be a bogus DNS entry on your internal DNS server for the targeted domain.