title: Multicast listening and interface IP address change
body: <p>I am binding to a multicast group and port to listen a multicast stream.  Since adding the group membership (via IP_ADD_MEMBERSHIP) requires specifying a specific network interface, what will happen when that interface IP address changes?</p>
  
  <p>Do I have start again with a new socket and add membership? This is related to Linux/C environment. I do see some packets comming in without changing IP, but I feel I have to restart.</p>
  
  <p>thanks,
  gl</p>