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

I send and receive UDP is a small program

Simulator can be well received by the real machine information, everything is normal; But two real machine or fax machine to send information to the simulator, then 95% of the information is not received.

Where the network simulator and real machine connected to the same network, all come with a wireless router.

I feel like a wireless network problems, but saw wireless router setting items, Which did not find connection, the wireless router is TPLINK. Now very depressed, do not know the machine set up, or network problems.
Reply:
Add the wireless router WAN port is not the case as the switches used
Reply:
Real machine IP is 192.168.1.123 and 192.168.1.105
Simulator is 192.168.1.103

Gateway is 192.168.1.1