Question

I am working on an application that will receive RTP packets from another local service over UDP. Early in the protocol, I receive a message with the IP address from which I’ll be receiving these RTP packets, but the port number will be given as 0 (zero) … I’m to open my UDP socket using an ephemeral port. My response to the given message will contain the actual port I’ve opened so the sender can know where to direct the packets.

My networking library is an implementation of sockets with boost::asio. Where can I find clear information on how to open such a socket without specifying a non-zero port i.e. use an ephemeral port? Searching the boost docs for “ephemeral” doesn’t give me networking results.

Of course, I’m open to seeing an actual example, but finding good documentation would also be just fine.

Thanks.

Answer 1

I would question using ephemeral ports like that, but … – you can bind your UDP socket to port 0, then use local_endpoint() to retrieve actual port assigned by the OS.