title: How to Multicast (send) to first NIC?
body: <p>I found recently that if I have a dial-up connection (this is for a kiosk) and a local area network connection, when the dial-up connection is established (with internet access), my multicast sendto would default to the dial-up rather than my LAN NIC. This made the multicast go out to the dial-up connection instead rather than to my LAN which has several multicast subscribers.</p>
  
  <p>I understand that I need to use IP_MULTICAST_IF to set the interface on my multicast socket. Question is how do I enumerate the interfaces and how do I use IP_MULTICAST_IF in setsockopt?
  On the kiosk Windows XP Embedded, there's always going to be just one local area connection NIC. How do I get this interface and pass its IP address (is this what IP_MULTICAST_IF is expecting??) to setsockopt?</p>