Apologies for digging up an ancient thread, @GeeBee2, but I'm trying to do exactly what you describe, for exactly the same reasons. I need to send a broadcast packet from a specific port. Then, the [third-party] service will, by convention, reply to my broadcast on the port I sent from I see all of the above, but for the life of me, I can't get it working myself. Do you happen to have a working code sample you could share?