403 Forbidden error in Firefox only, works in Chrome and Safari

Question

I have a Firefox quicksearch bookmark that runs a Maxmind query. This worked until recently. I type 'ip 82.176.230.15' (for example) into the URL bar and it queries Maxmind to retrieve the location of the IP:

http://www.maxmind.com/app/locate_demo_ip?ips=82.176.230.15

Within the past week, for reasons unknown, I now get a 403/Forbidden error when I try to access Maxmind.

"You don't have permission to access /app/locate_demo_ip on this server"

Strangely, the same URL is accessible in Chrome and Safari. I can also access the same URL with Firefox, Chrome, or Safari on my Mac.

I've deleted all cookies, disabled all addons, and still can't get it to work. Any idea what could be happening? I know that the 403 has to come from the server, so I don't know why it would work in other browsers. And it's been going on for days, definitely not some glitch on their server.

Answer 1

Get an HTTP debugger like firebug or fiddler (not sure that will work with FireFox, but probably if you set it up right)

Look at the difference between using your quick bookmark and just typing the URL. The server could return 403 whenever it feels like -- see if there's any difference, and what it is.