Client Server Networking Problem

[iva]

Okay, this is a 6 years old post, but I have had the same problem already twice, so next time when I google for the solution, I will find this post. I don't know if this would solve OP's problem, but I had the same situation, communication worked from client to server, but server to client never worked. It turns out, if I use server's machine name instead of server's IP address, miraculously everything started to work.