Methods to establish communication between a first and second device via at least one intermediate device comprise, at the first device, generating an offer data packet comprising a second device address, which includes a first identifier indicating a public key associated with the second device; transmitting the offer data packet to a first intermediate device for transmission to the second device based upon the address of the second device; receiving an answer data packet via the first intermediate device, the answer data packet including network information associated with the second device; establishing a communication channel with the second device based on the network information received; receiving over the communication channel a first handshake data packet including a public key; calculating a second identifier based upon the public key; comparing the first identifier with the second identifier; and warning if a relationship between the first identifier and the second identifier is not an expected relationship.