Peer to peer over 3G

Question

Hey I'm trying to get a CFStream connection going over 3G. I can get it working over wifi using the host name, but when I try to connect directly to the ip address it fails.

Is there a guide out there on how to connect over 3G?

Thanks ASH

Answer 1

When you are connected to 3G then you are usually behind a router that implements some 'NAT' scheme. This means that your iPhone gets a private internal IP address on the inside (the 3G network) and a shared 'real' public IP address on the outside (the Internet).

This is all fine when you are just a client connecting to services on the Internet, but it will fail horribly when you try to connect to other clients in the same situation.

There is no simple solution for this. Programs like Skype work around this problem by using intermediate servers with public IP addresses that can relay network traffic between hosts behind such 'NATted' networks.