Ubuntu Networking :: Cannot Open Port 80

I just installed apache. I didn't change the configuration files at all except add Quote: # added servername to avoid the could not determine fqdn error ServerName myname.homelinux.org to apache2.conf. Apache is working locally (I get the `it's working' screen at [URL]). However, I cannot access my computer from an external computer by going to [URL], which is equivalent to [URL] -- [IP address changed slightly for privacy] Here is a screenshot to my router settings. I disabled the filter for port 80 on the router. here shouldn't be a firewall, unless it's automatically installed with ubuntu 10.4. (sudo ufw status says `inactive'.)

I checked my ports from [URL] and indeed port 22 is open (ssh-ing into my computer externally is not a problem), whereas port 80 is closed. What step in opening up port 80 am I missing? (I also made sure my ISP isn't blocking port 80.)