How do I set up a socket so it can be accessed outside my LAN?

I can use the loopback address and the LAN address, but if I use my IP address, I can not connect to it with my client. Which ServerSocket constructor should I use for this? Also, when I print out that a Serversocket has been created, and give the information, it gives the correct port number, but gives 0.0.0.0 as the address.

This is not for an assignment, just a personal project. I am trying to make a non browser based chat server/client.

Thanks in advance