[X4U] Damn Comcast

[wilkinw]

2.66, Intel Duo Core Xeon 8 gig memory, 4 - 1 terabyte drives, X.5.5.

I really feel embarrassed about this and should know this. Got an  
email from Comcast stating that they have blocked port 25 for spam. I  
don't spam, the only other users of my computer is my wife who only  
uses yahoo email. So I know that Mac Mail uses port 25. How would this  
happen? Also even though Comcast states that they have blocked port 25  
it still seems like me emails are going out. I sent a test email to my  
daughter and my work email and they went thru. Any help would be  
appreciated. I tried to check if you can change the ports in mail but  
don't see any options, Wayne.