I've a question regarding decentralized server:
I don't know how to describe it but I'd use WinMX as an example:
WinMX doesn't have a centralized server. So when you connect
it just search for other WinMX users randomly.

So how does it search for other WinMX users without referring
first to a centralized server?
My first thought is random ping, but this is impossible since
IP has 255^4 combinations.

Any ideas?