Hello group,
I'm trying to set up a UDP link between a mobile client on a GPRS network, and a base server, both behind NAT.
Currently I'm getting the client-> server leg OK, and I'm replying to the translated address on the client's network, but I've just realised that I need to deal with the source of the server's reply.
So if the server is listening on, say 85.1.1.66 : 7000 , it's no good me replying from an internal private address, as this will get NATted as the packets leave the server system.
I have to make sure my return message originates with 85.1.1.66 : 7000 don't I? Currently port 7000 is being forwarded to my private address inside the server's firewall. Maybe I just need to send my reply on port 7000. Does that work in the reverse direction (can't try it til Monday)?
Sorry if this is a horribly newbie question, but I'm an applications programmer whose been chucked off the UDP cliff :-)
If this is not the likely problem, could someone just suggest how addresses etc affect the passed messages in the client NAT / NAT server scenario.
cheers, Jim