We have a webserver, and it is on a workgroup and it forwards smtp traffic to and smtp server on testdom.com (e.g.). The problem is, it will only send mail to recepients in the testdom.com. It will not send to anything outside, and generates a relay error. The from address that we are using is email.testdom.com
I can get it to work by adding the webserver to the testdom.com domain. But i don't want my webserver to be on the domain, i'd prefer to keep it in a workgroup.
Is this a feature microsoft have introduced? It used to work about 6 weeks ago.