ProudNet server is Proud::CNetServer instance. ProudNet server performs as followed.

Accept or manage the connection from ProudNet client.
Perform the communication with client. : More details on Communication between hosts .
Manage the group of peer-to-peer communication between clients : More details on P2P Group .
ProudNet server also plays the role of relay server with relay function of peer-to-peer communication. (More details on Overview of peer-to-peer communication between clients )

Communication relationship between client and server