Application Control in TMG 2010

Most things are possible. You would need to access the site/service, track the protocols/ip addresses used then put deny access rules in place above any more open allow access rules. As each service is different there is not a generic 'catch all' setting. However, there are a large range of existing Category sets and Types pre-poulated in TMG that you can choose from and add to the TO: section of the deny rule but these are not necessarily going to cover every eventauality.

Hi Keith,

Thanks for your prompt reply.  Please correct me if I'm wrong... what I understand from TMG and your above comment is that to block the actually application itself we have to find the ports they use and block those ports.

I understand that pre-defined category sets will only block websites that fall under that particular category, not the application itself.  Am I correct in saying this ?

Regards.

Yes - spot on. It is the protocol and ports along with header and content information.
Once you have identified thee - and it can be a painful exercise, then you can vreate a filter or a simple rule based on the results.

Very helpful replies, it is crystal clear now.