Choosing multicast network interface in Python.

Question

I have a server with two separate Ethernet connections. When I bind a socket in python it defaults to one of the two networks. How do I pull a multicast stream from the second network in Python? I have tried calling bind using the server's IP address on the second network, but that hasn't worked.

Answer 1

When binding your socket, try the values mentioned here:

For IPv4 addresses, two special forms are accepted instead of a host address: the empty string represents INADDR_ANY, and the string '' represents INADDR_BROADCAST.

INADDR_ANY is also known as the wildcard address:

Sockets with wildcarded local addresses may receive messages directed to the specified port number and addressed to any of the possible addresses assigned to a host`

More here.

Answer 2

I figured it out. It turns out that the piece I was missing was adding the interface to the mreq structure that is used in adding membership to a multicast group.