RV50 DMZ & IP Passthru Port forward issue

Hi there,

I have multiple RV50 routers connected to Ubuntu physical single board computers. The SIM cards are connected to an isolated 4G network and receive a unique IP from the provider.

System information:

These routers are configured with DMZ on the first host and IP passthrough as shown below so that the provided unique IP is passed through to the single board computer that’s connected to the modem and runs Ubuntu. AT is configured with telnet on port 23.

Now the routing in this network is configured in a such way that these IPs have tcp access between them, so that one can make http requests or ssh to another. The ssh session ends up to the DMZ host, in this case the computer running Ubuntu.

Each Ubuntu system connected to one of these routers has an http server listening on port 8080. Now in theory, an http request on port 8080 to that IP should end up in the linux system just like the ssh session, but instead it’s getting timed out.

I have tried enabling port forwarding in the way shown below (as well as other variations, but most guides online suggested this)

But after this change the result is the same, the http request is getting timed out. At the same time the SSH session ends up at the ubuntu PC.

Does anyone have an idea on how to fix this?

Hi Everyone,

It turns out this was an MTU issue, which is always the culprit when nothing else explains it :sweat_smile:

Can’t find how to close this thread, could a moderator do that for me?