I had problems with the ASUS RT-N56U router forwarding ranges with XP and W7x64 PCs.
I updated firmware to the latest and could open UDP:23456, 6073, 2300. But when I entered 2300:2400 FSPortTest gave time out errors from port 2301 on.
Eventually I tried leaving out the 'local port' number in the entry dialogue. This cured the problem. This advice from Portforward.com was incorrect for this router.
Maybe this will help someone else. In the meantime, portforward.com should amend the above section.
Regards,
John
