the content length is 803, here is a sample data (received on Hercules):
POST /?imei=865546040689768&serial_num=1104633324 HTTP/1.1
the PHP page is programmed to receive both GET and POST packages and query to an SQL server, the result is shown below:
As you can see, i can receive both IMEI and Serial by GET but POST array length is 0. I think this problem comes from the server and not the router, so thank you anyway.