When the Network Games Setup offers two IP addresses

[Templer]

I have tried to establish a connection with another player – unsuccessful.

Why the Network Games Setup displays two IP addresses?

 

[Dave 'Arjuna' O'Connor]

One of those will most likely be your local IP - ie the IP address you use internally and the other will be your external IP address. If you are playing someone over your local net then use the local one, otherwise use the external one.