Mail (not!) from my own postmaster

[Paul Franklin]

I just got an e-mail which claims to be from postmasteratyugmdotorg, 
which resides on my kolab server, stating that an e-mail I attempted to 
send could not be delivered.  Of course, it originated from a host 
identified only by IP address.
Is there a setting to cause Kolab to reject that as spam since no one 
off site should be masquerading as our postmaster?
--Paul

-- 
Paul Douglas Franklin
Computer Manager, Union Gospel Mission of Yakima, Washington
Husband of Danette
Father of Laurene, Miriam, Tycko, Timothy, Sarabeth, Marie, Dawnita, Anna Leah, Alexander, and Caleb