Some of you have been asking about how to setup a website at home.  This article covers how to setup "port forwarding" on a router.  Different routers will have slightly different GUI's, but the basics are the same. You designate a certain port to be forwarded (port 80 for standard website) and then set which internal IP address is going to host the webserver.  The public will use the public IP address assigned to the router.  This address will also be the address that is paired up with the domain name in DNS.

https://lifehacker.com/127276/geek-to-live--how-to-access-a-home-server-behind-a-routerfirewall