How do I block SPAM emails that seem to be coming from my domain?

[mspain]

As the subject suggests, is there a way to do this from Exchange? For example, I received SPAM this morning from somebody claiming to be br@mydomain.com. There is no user br in Active Directory.

Any help would be greatly appreciated!

 

[58sniper]

[google]Exchange 2003 Recipient Filter[/google]
[google]Exchange 2003 tarpit[/google]

Pat Richard
Microsoft Exchange MVP

 

[Zelandakh]

SPF record.