1. Native firmware in 2008 was not functional, as I put something more complicated the Internet via dhcp in the settings — out cosmic glitches. after installing open-wrt router works for several years.
2. In fact, the question, regardless of the firmware:
2.1 Specify the port, for example 9808 to access the admin panel from the Internet if necessary.
2.2 to Register a static IP address for the server, where it is necessary to map port 80 (and, most likely, it will not be a port but a big range)
2.3 Create actually forwarding port 80 to the internal IP address of the server 192.168.1.1, for example, and specify on the web server that it runs behind a NAT in the settings of apache, IIS or what have You.
Or, to say in the settings of the router that all traffic transparently it is forwarding on specific IP.