A method and a system for using relays for network optimization in IP-based communication networks. The method includes negotiating a communication session between two peers connected to the Internet via a signaling server, at least one of the two peers having data traffic restrictions and requiring a relayed route to connect with the other peer; identifying, by each peer, a plurality of candidate contact addresses, including IP address, port and protocol, that the peer can send to the other peer, so that the other peer can find a route to connect to that peer; filtering out any candidate contact address of the plurality of identified candidate contact addresses that is not a relayed candidate contact address, providing a list of relayed candidate contact addresses; and establishing a connection between the two peers via one relayed candidate contact address of the list of relayed candidate contact addresses using a TURN server.