I'm working on a script that uses the CPAN module IO::Socket::Multicast. My script opens a multicast socket and adds two groups, '225.0.1.1' and '225.0.1.2' on the same port 6760. Reading data is no problem but I need to be able to determine when a datagram comes in which group provided it. Any ideas on how to extract that info? I used the sockname and peername calls but they didn't identify the group IP. Instead they gave me 0.0.0.0 and the IP for the server sending the UDP datagrams.

Any suggestions?