Why can't I access my web server by it's IP address outside my LAN
I've never actually made a web server until now. I set up a very very simple server which is running sinatra on my desktop. I used a website called "whatismyipaddress.com" and it said the address was "18.104.22.168" and I have been trying to access it from computers that don't access the net through my router (linksys WRT 120n) and I haven't had a lot of success.
It works fine when I try to access it by its ip address on my LAN, and I was able to ping the ip address from one of my school's computers (which is weird considering they have a firewall which I was expecting wouldn't allow that.)
I have been spending the last couple of hours changing my router's firewall settings, and nothing seems to work. I have already set it so that it should allow web server access on port 80 (presumably it is talking about web servers on the LAN), but it still doesn't work.