Peer Exchange (PEX) is a method of discovering new peers via other peers, rather than the tracker. It allows Transmission to attach to the swarm much quicker. - PEX is automatically disabled for privately tracked torrents. The feature is compatible with both Azureus and µTorrent peers. + PEX is automatically disabled for privately tracked torrents. The feature is compatible with both Vuze and µTorrent peers.
Transmission encrypts the connections it makes with other peers when necessary, using the RC4 cipher. The implementation is compatible with other clients such as Azureus and µTorrent. It is always enabled, however you can set Transmission (Preferences -> Peers) to prefer encrypted peers or to ignore unencrypted peers completely. +
Transmission encrypts the connections it makes with other peers when necessary, using the RC4 cipher. The implementation is compatible with other clients such as Vuze and µTorrent. It is always enabled, however you can set Transmission (Preferences -> Peers) to prefer encrypted peers or to ignore unencrypted peers completely.
Note that the latter option may make Transmission unconnectable in some swarms. The encryption feature does not mean your session is secure or anonymous, it is merely a way to avoid the traffic shaping measures some ISPs have implemented.