[idle_zealot]

Ssh and p2p stuff are two examples off the top of my head. For p2p, you lose the ability for peers to initiate a connection with you if you block incoming traffic.

[staticassertion]

Why not block all incoming connections except on those ports?

[konart]

That's what you usually do (preferably on your router if you are using one).

But the article says "and check Block all incoming connections". That's my point.