Windows Firewall Questions

[Chimp Paradox]

I have been experiencing file sharing difficulties across my network so Ive turned off my firewalls for now. However when I was exploring the advanced settings, I see that what people normally refer to as a firewall are either related to the private profile or a public profile. But that there is a third type called domain profile. What is that?

Second, I assume private firewall just refers to intra computer on your own network?

 

[Chimp Paradox]

is WAN not a network at all right? Ie your computers are connected to a router, not the WAN?

So is a Domain like an overly? A overly which creates different domains within the same network?