Symantec Brightmail Gateway issue

Hi All,

We use Symantec Brightmail Gateway 9.0.2 and Exchange 2007 server. Recently, we always received fake emails from Intermet, but these fake email used our company's email addres. I want to block all emails with @mycompany.com which come from internet, but not block our real emails to send out to Internet.

Any body know how to do it? I think that I should setup content filter policy, but I am not sure about it.

Thanks in advance.