Legal controversy
Peer-to-peer technologies are rarely considered in and of themselves to be illegal.However a frequent use of many peer-to-peer technologies is file sharing of materials without permission of the copyright owner, and this is illegal in most countries; unless a license has been granted for the exchanged files, which permits redistribution (such as GPL or GFDL), or if exchanged materials have entered the public domain.Other uses of peer-to-peer such as telephony are not typically nearly so controversial, although provision of telephony is restricted in some legal jurisdictions around the world.