Port Scan nuisance

We are using SEPM 12.1. After setting up new firewall policies, users all over are getting port scan popups. I have not been able to find a solution to this and hope someone has any ideas.

Examples:

2    9/25/2013 8:14:30 AM    Port Scan    Minor    Incoming    TCP    205.138.173.231    00-A0-C8-56-81-B9    #.#.#.#    #-#-#-#        xxxx    xxxx    Default    1    9/25/2013 8:14:06 AM    9/25/2013 8:14:06 AM    Somebody is scanning your computer.   

Somebody is scanning your computer.
Your computer's TCP ports:
1657, 1656, 1658, 1659 and 1661 have been scanned from 205.138.173.231.

Thanks