I am trying to get a dual homed computer working receiving multicast messages using ASIO and there appears to be all kinds of problems. Firstly, when trying to receive multicast traffic ASIO will only ever bind to one address. Even explicitly providing an IP address to bind to will not convince the OS to allow you to bind to that address. In my case it always attempts to bind to the device that is connected to the WAN. Secondly, even if both devices are connected to the same network, ASIO will only receive multicast packets on one interface. If that interface is disconnected it will no longer receive multicast packets. I have tested this using both the any address and with explicit IP addresses over multiple sockets. Neither seem to work. Disabling all interfaces except the one receiving Multicast traffic allows ASIO to bind to the last remaining interface and receive packets properly. I have seen this problem using ASIO 0.3.7 and both my own programs and the default multicast receive included with ASIO. I have also been able to replicate it using Windows XP SP2 and Fedora Core 6 ( 2.6.20-1) Any explanation or help would be greatly appreciated Dan