Ideally block by exe name either by firewall or applicatiojn control. See policies here
https://www-secure.symantec.com/connect/downloads/firewall-and-application-control-policy-block-peer-peer-applications-0
This should help you
https://www-secure.symantec.com/connect/articles/what-do-p2p-applications-do-and-how-block-peer-peer-applications-p2p-using-symantec-endpoin
Hi,
Thank you for posting in Symantec community.
Refer this similar thread: https://www-secure.symantec.com/connect/forums/block-skype-all-types-messenger-and-teamviewer
Do you need more assistance with your problem or were you able to get it resolved? If you could post an update for followers of this thread that would be most helpful. Otherwise, if resolved, you can close the thread out by clicking the "Mark as solution" link at the bottom left on the most helpful post. If multiple posts helped to solve your problem, please click the "Request split solution" link at the bottom left, select the most helpful posts and click the "Submit" button. This will benefit admins looking for a resolution to the same problem. Thanks and take care, Brian