Port forwarding suddenly stopped working

[Ingenious]

I have a 7800N which has been running for over a year now and apart from this problem seems to be working fine.

I have half a dozen IP cameras connected plus an "always on" desktop PC (which acts as an IP camera recorder running WebcamXP software).

All the cameras plus the PC have been set up for port forwarding. So I can access them remotely via my static IP and the port number.

Suddenly, all port forwarding has stopped working. I can access the cameras when at home, either via the local network IP and the port number, or my internet IP plus port number (obviously the router sees the IP and realises it's actually local because I am connected to it!). But I can no longer access any of the cameras or the PC from outside of the home network, over the internet.

I have *not* made any changes to the port settings. My IP has not changed. The cameras have not changed settings or addresses. The fact I can access them locally proves the internal IP addresses and ports are correct.

The forwarded port settings are all still there, unchanged. Why in earth would this suddenly stop working? But I can no longer connect to any camera when I am away from home, or the home PC.

The only thing to note is that the router kept dropping the internet connection a few weeks ago and I had to keep switching it off and on every few days or so, I think it was getting a little hot (seems fine now).

Any suggestions on where to start with this one, given that it was working one day and not the next?

Screen Shot 2014-03-13 at 23.39.53.png

[Ingenious]

Just to add, I have tried the following:

Updating to the latest firmware.
Complete factory reset.

I then tried entering one of the port forwards again from that list, the one that allows me to connect to my PC's IP camera web server over the net.

Again as before, I can access it locally via that port. But I cannot access it from over the internet.

If I just type my home IP address (with no ports) from externally it connects to my NAS's webserver, which proves that the router is at least responding to something. But why not forward the ports anymore?

[billion_fan]

Just to add, I have tried the following:

Updating to the latest firmware.
Complete factory reset.

I then tried entering one of the port forwards again from that list, the one that allows me to connect to my PC's IP camera web server over the net.

Again as before, I can access it locally via that port. But I cannot access it from over the internet.

If I just type my home IP address (with no ports) from externally it connects to my NAS's webserver, which proves that the router is at least responding to something. But why not forward the ports anymore?

Well port forwarding is working (or I should say UPNP), as you can access your NAS from the outside (I assume is running on port 80)

Check the gateway address on your camera's and home pc so make sure it points to the routers IP address (as you can access them locally, this could point to the gateway address being incorrect)

[Ingenious]

Thank you billion_fan you were spot on with the gateway address.

That was set manually over a year ago on the cameras (along with the fixed IP address on the network, etc). For some reason, the gateway address seems to have changed, no idea how or why, this is what stopped the cameras responding. I changed it on each cam to match the gateway address shown on the default Billion login screen and it all works again.

Ta!