Monday, January 5, 2009

Broken Port Forwarding



I've spent over an hour trying to get my new D-Link DCS-910 working from outside my home network. I've done this kind of thing a hundred times, basically I'm setting up port forwarding so incoming connections to my home router will get forwarded to my camera.

I was forwarding port 8085 to 10.1.1.205:8085 but it just wasn't working. Inside my network I was able to go to 10.1.1.205:8085 but I wasn't able to get to foo.mine.nu:8085 (where foo.mine.nu resolves to my home network courtsey of DynDNS). After trying lots of different ports and even reloading the firmware on my Netgear WPN824, it turns out it was something simple and had nothing to do with the Netgear. The problem was the default gateway setting on the D-Link camera. I had setup the DCS-910 to use the static IP address of 10.1.1.205. I didn't bother to set the default gateway. For some reason, this worked fine when I was going from some other machine on my 10.1.1.x network, but failed miserably when trying to connect from outside.

I don't disagree that leaving the default gateway set to 0.0.0.0 is a problem, I'm just suprised that the camera would work on my LAN but fail when accessed via port forwarding.

If you have a similar problem with port forwarding, make sure the device you're forwarding to has its default gateway properly set! Lesson learned.

Disclaimer: My camera really isn't at foo.mine.nu. I'm just using this FQDN as an example.