553 Sender is spoofed

[OroITDirector]

My exchange server can't send to one domain. The result of the smtp transmission is 553 sender is spoofed. I do not have SPF records associated with my mail server, but will have them shortly as I am hoping that is the problem. Any other suggestions? We also use Postini to check all of our mail before sending to our mail server, could that have anything to do with it? Our MX records point to Postini servers instead of our own.

 

[58sniper]

What does your reverse DNS entry look like? Does it match the name in the banner message (the one sent during the ehlo handshake) from Exchange?

Pat Richard
Microsoft Exchange MVP
Contributing author Microsoft Exchange Server 2007: The Complete Reference