actaully there's probably a pretty small chance that it's being blocked. Usually the only port an ISP will block is 80.
Can your router allow WAN administration? If so, turn it on
for a moment and then try to access that from a remote site (I'm assuming a friend is testing this for you or smoething). If you can't get to the router than you know it's not your LAN config that's the problem. If you can get to it, then something is definitely wrong with your LAN config. Possibly something like a reboot is needed and you haven't yet done that? Remember to turn off remote (WAN) admin after the test.
jlanka (. .)