I'm developing a VoIP IOS app using SIP protocol. I have my own SIP parser library and I use GCDAsyncUDPSocket to send data to the server.
The problem is that I can't reach the server on double NAT with my app. I do PING and the server responds immediately PONG, but when I send a SIP package, I can't even reach the server.
I try to reach the server with other clients like Zoiper or Media5 and works perfectly. So I think i'm doing something wrong.