[atburrow]

Blocking at the router level could work. I figure if you have multiple PCs on the network, it could also be easier to maintain.

[mondoshawan]

The problem with this is that unless you're doing deep packet inspection, they can patch the system to route every call through the same frontend IP -- including services you actually want to use. It'll work for the short term, but probably not long term -- doubly so if they just route everything over HTTP.