What features does Windows Firewall block on games?

[Terpie]

I recently reset my Windows Firewall settings, so I ended up getting the "Windows firewall has blocked some features of this program" message whenever I launched a steam game. I ended up NOT allowing the games to communicate through the firewall, but I was still allowed to play online and did not notice any differences.

With that being said, what "features" are blocked then, since nothing seems different even though I am not providing access?

[mimizukari]

online functionality often.

it may not be immediately obvious, but you are blocking some ports from working for that game which can cause trouble