How not hybrid p2p programs know about others peers?

Question

I know that hybrid p2p software use a centralized node to get information about the others peers to connect to them, but in full p2p software how this is done? they connect to a sort of vpn in a range of ip's so them can check what ip is been active or something?

Answer 1

Yes, full P2P nodes need to keep a list of neighbours classified by some criteria, in order to know on which they should connect to. More details here :

However, in order to route traffic efficiently through the network, nodes in a structured overlay must maintain lists of neighbors that satisfy specific criteria. This makes them less robust in networks with a high rate of churn (ie with large numbers of nodes frequently joining and leaving the network)