WIZ750SR-TTL - UDP to serial works, but serial to udp does not


I am using two WIZ750SR-TTL boards for a project. Basically what I want to do is send data from a device ( via udp packets over ethernet to a WIZ750SR board ( which will then convert the packets to serial data and send them to the main board I am using (Atmel SAM4S). Then on the Atmel board, I take the serial data that I received from the first WIZ750SR board ( and send it directly out via another serial connection to another WIZ750SR board ( which will then send out the data as udp packets over ethernet to a second device ( Note: As soon as I receive the serial data, I transmit it back out over the other serial port, and I do not modify it in any way.

I am accurately receiving the packets over serial on the Atmel Board, and the Atmel board is transmitting them out on the second serial connection. However, the second WIZ750SR board ( is not sending out the udp packets to the second device ( I have even confirmed this by using wireshark, and no packets are sent out. I have also tried going in the opposite direction and sending from the second device to the first device, and that did not work either.

I’m just wondering if I have some type of configuration wrong for the WIZ750SR boards or maybe I need to modify the serial data that I receive before I transmit it out on the other serial port. I had assumed that basically the WIZ750SR board receives the udp packet, strips off the headers, and then just forwards the data (payload) over serial. So I do not see why I would have to modify the serial data coming in to the Atmel board before I transmit it again. I also assume that when you send serial data (payload) to the WIZ750SR board, that it then adds on the necessary udp headers and then sends it out over ethernet. What am I missing?

The configuration for the first WIZ750SR board is shown below. The second device is configured the exact same way except for the Local IP is, and the Remote IP is