My original http server with a dedicated ip address won’t work behind a router since I moved to LA and installed cable modem.
Here is the way: no matter which way, wired or wireless, you use to surf the internet, the ip address behind a router became the intranet address like 192.168.*.*. The router has 2 address: one for wan, internet address which your isp supplies; the other for lan, the first intranet address usually 192.168.0.1.
First modify the httpd.conf file to make the address become your machine’s lan address like 192.168.0.* if you don’t have domain name. Otherwise go to you domain name setup, make it point to your router’s wan address. For linux, I changed the hosts file, make the domain name alias pointing both to 127.0.0.1 and lan address.
Then http://192.168.0.1 (router’s lan address) , make some forwarding there, which depends on different routers.
More details, google: website behind a router