I am doing some consulting work for a client who has a Firebox III as a firewall. We have normal ports open including 80,21,443,5900,3389 etc. and am able to browse every site known to man however the one thing we can not do is go to mapquest and see a map. The map space loads along with the larger/smaller slide bar on the left side however the map itself never loads. If I connect outside the firewall or from any other site the maps load fine. This is not a browser configuration issues as I use several browsers and they all work outside the firewall. I have opened up UDP ports 20 to 22000 as a test but have been unable to figure out what ports outside of 80 and 443 are needed to make this work.
We can access google maps and all other map site fine - is is only mapquest.