Peer-to-peer file sharing (P2P) systems like Gnutella, KaZaA, and eDonkey/eMule, have become extremely popular in recent years, with the estimated user population in the millions. An academic research paper analyzed Gnutella and eMule protocols and found weaknesses in the protocol; many of the issues found in these networks are fundamental and probably common on other P2P networks.[1] Users of file sharing networks, such as eMule and Gnutella, are subject to monitoring of their activity. Clients may be tracked by IP address, DNS name, software version they use, files they share, queries they initiate, and queries they answer to.[1] Clients may also share their private files to the network without notice due to inappropriate settings.[2]
Much is known about the network structure, routing schemes, performance load and fault tolerance of P2P systems in general.[3] It might be surprising, but the eMule protocol does not provide much privacy to the users, although it is a P2P protocol which is supposed to be decentralized.[4]