Note a server will always have either or both IP/Port and ID, it will never have none. ID e.g. CSteamID is used by SteamNetworking and SteamNetworkingSockets for connections. IP/Port is more offten used with 3rd party transports such as KCP, TCP, UDP, etc. A server may have both as a server may handle both SteamNetworkign and other 3rd party connections.