Open TCP Port Not Recognized By Router

TCP/IP Chip W5500
1

I have designed over a dozen boards that use the W5500 for TCP communications over a LAN. I recently tried to access the W5500 on a board which was configured in TCP mode and was in the Listen state. If I use a browser (like IE11) over the LAN, there is no problem connecting to port 80 of the W5500. However, if I set up my Netgear FV318 router for port forwarding to port 80 of the same W5500, the router does not recognize that the port is open!!

I spent considerable time (and money) working with the tech support people at Netgear to verify that the problem was with the W5500 and not the router.

I further confirmed this problem when I attempted to connect to the W5500 through the LAN using an ESP-8266 Wi-Fi device. The ESP-8266 successfully connects to an IP camera on the LAN but fails to connect to the W5500 on the same LAN.

I would like to find someone who has anyone successfully used port forwarding with the W5500 as the target device.

2

As long as you were talking to support, you most probably have much more technical information about the incident. Can you share it please? Did you investigate packets and their flow?

3

Please check steps below.

  1. If you don’t use DHCP in a target, change to DHCP.
    And then check the status of target in a router.

  2. After No. 1, if a target isn’t recognized in a router, you must have the connection of TCP between a target to external IP once. In this case, it doesn’t matter DHCP or Static IP. Please check the status of target in a router.

  3. After No.2, if you can recognize a target in a router, and then please use port forward function in a router.

In my case, I used a WIZ550SR-EVB and ipTIME-A2004plus router. I succeeded.

Thanks.