Hi all
I play M2H_Networking_Tutorial , its work very good on local network with local server :), but when play it on Server out side of local network its not work 
You need to setup a master server. Read the tutorial carefully again.
If you’re not using the master server with NAT punchthrough, you need to forward the ports that you’re hosting the game on in your router for the network IP of the machine on your network that is hosting, or put that machine in your router’s DMZ.