Hello, I have a problem with the multicast mode of udp-sender. On Solaris 10 X86 and Solaris 10 Sparc it is the same error. One udp-receiver works perfect (unicast), but if I use two udp-receivers (I think then udp-sender switches to unicast mode) the sender gives the following error after starting the transfer with the anykey on the server: Udp-sender 2009-10-31 Set multicast send interface: Invalid argument and then the server stops. The Error is with udpcast-20091031 on Solaris 10 sparc and also on Solaris 10 x86! I compiled it with a hack, because the missing strndup in Solaris. I also have compiled udpcast-20070602 without a hack on Solaris 10 X86, because the news are saying it is Solaris 10 x86 ready. But I got the same error with the invalid argument. The same error occurs, when i set --ttl from 1 to 2. I think it is not a problem with the hardware or the network, because udpcast with the same hardware , but with Mandriva did work. It seems to be an Solaris related issue. Two Solaris-receivers with one Mandriva-sender did also work. Only the sender breaks on Solaris. Can you please help me? Best Regards Ralf