3.1.5.30 DPSP_MSG_PING
When a DirectPlay 4 client receives a DPSP_MSG_PING message (section 2.2.42), it MUST look up the player specified by the IDFrom field in the Player List. If the ID does not represent a valid player, the client MUST ignore this message. Otherwise, the client MUST send a DPSP_MSG_PINGREPLY message (section 2.2.43) and echo the TickCount field. It MUST also increment the Player.ChatterCount.