Im having a major problem with relaying email. This is the scenario.
Im using helpdesk software on a server in the DMZ. I need to reply to emails from the helpdesk software to external email addresses. I can reply to internal emails from the helpdesk software with no problems.
On the Helpdesk software I have it setup for SMTP to point to my Exchange 2007 server on the LAN.
I can telnet from my helpdesk server on port 25 to the Exchange server and from the Exchange to the helpdesk server with no problems.
I have setup a Receive Connector in Exchange and have the remote server as the Helpdesk server. And have the Anonymous users selected.
I have followed the following below
And had no luck.
The error I get in the log of the Helpdesk software is
550 5.7.1 Unable to relay
Any help on this would be great.