Why can normally receive UDP broadcast on the simulator, but can not receive broadcast on a real machine

I was a small program to send and receive UDP broadcast, I was in the simulator, it is normal to send and receive radio, but I put the program on a real machine, fax machine can only receive its own broadcast radio does not receive anything else, is what reason? ? ?
Reply:
What is your real machine on the network using? If it is wifi, then with a LAN should be able to receive.
If it is 3G or 2G network, this is a close reach.
Reply:
Upstairs has a point;
Simulator and network fax machine uses a different cause this problem.
Simulator should be less restricted, on a real machine, and if the address is no problem, the server broadcasts data should also be received
Reply:
If the network is not restricted words
Reply:
Computer simulator is used where the LAN

If it is wifi Internet fax machine, then
Wireless routing problem should be cut off the broadcast domain
Fax machine you want your computer to interact with the network under study, then penetrate it

Reply:
Your computer should be in the LAN, the WAN in real machine. LAN broadcast WAN how close to Oh, the other you can not broadcast to the WAN. You can find your real machine ip address, send udp packets to it. It can be received. But it sends data to your computer is not received, unless you do port mapping, port mapping router to your computer go above