How can i run my unity standalone exe in various system using networ

Hi,

i have this problem i describe it below.

i have a two unity standalone exes i want to connect it through the network i wrote the scripting for that in that scripting i gave the ip for another system which is my friend system he near with me. Totally two exes one i had and another one i gave to him now i run it to the both exes. i gave my friend ip address na so if i connect it its not connecting. But if i give my ip address and run the both exes in my system it is working correctly. I dont know why now only i start the code for networking so please help me apples.

Thanks