The Relay software written by F1OON for Windows 98SE, Me, 2000 and XP grabs the multicast data and provides it on a TCP/IP Unicast port so that programs can connect to the data stream without having to have IP multicast capabilities.
"Rufz" is the abbreviation of the German word "Rufzeichen-Hören", which means "Listening to Callsigns". RufzXP is an excellent training software for improving code speed and CW practice.