General : Losing my mind with port forwarding not working.

[AprilMay2211]

I configured my hub 5 to forward ports for my Plex and for my web server, and 'yougetsignal' and other internet port checkers confirm that the port is open on my virgin IP address, but any attempt to actually use the port fails.

I created a basic hello world nodejs app to display a simple web page on port 16565, and I set port forwarding in the router. Yougetsignal says the port is open, but trying to connect to it with a browser returns nothing.

In my local network, if I browse from my laptop to <server local IP>:16565 I see my hello world website.

I've installed ufw on my web server (where nodejs app is) and it allows traffic on 16565.

Looking at the logs on the server, I don't see the external connection attempt hitting the application layer, something must be blocking this traffic.

My local IP is defined as static in the hub 5. My virgin 82. IP address does not change and is the same on 'whatismyip' as shown in the router info page.

What does canyouseeme.org tell you ?

[AprilMay2211]

It says:

Success: I can see your service on 82.xx.xx.xxx on port (16565)
Your ISP is not blocking port 16565

If I browse to http://82.xx.xx.xxx:16565 (it's a basic no ssl test website), I get nothing back, no response, just spins.

In my home network, from another computer http://82.xx.xx.xxx:16565 actually works. From my guest network (virgin hub 5 guest network), I get the same problem as from externally.

Also, "sudo ufw status" shows on my server:

16565/tcp ALLOW Anywhere
16565/udp ALLOW Anywhere

[gunner45]

This is a failure of Hairpin NAT (NAT Loopback). Hairpinning means when a router receives a packet from LAN addressed to its own WAN IP, it should loop the packet back into the LAN and forward it to the correct internal host - but the hub does not properly support hairpinning. The solution is to put the hub into modem mode, use a router which supports Hairpin NAT and set up your port forward on the new router.

[AprilMay2211]

Originally Posted by gunner45

This is a failure of Hairpin NAT (NAT Loopback). Hairpinning means when a router receives a packet from LAN addressed to its own WAN IP, it should loop the packet back into the LAN and forward it to the correct internal host - but the hub does not properly support hairpinning. The solution is to put the hub into modem mode, use a router which supports Hairpin NAT and set up your port forward on the new router.

Thanks, so the solution is buy another router, when I just need my virgin to do one thing that is advertised as being able to do. I was afraid this would be the answer :-(.

Though I'm not really bothered if a device on my guest network goes out onto the internet only to return via the external virgin IP to access a device on the main network. Speed is not an issue here. What I want is external devices to be able to access the site I'm hosting.

No, the solution is not to try and do things in a weird way.
Your service is available externally to any other users, you verified that.
If you want it to connect to it internally just use the internal IP, it makes no sense trying to route packets out to a router and back in again.