IP PUBLIC TO DOMAIN NAME

I have 16 IP Public from ISP and I point one of them (IP Address) to my server using leased line.

Computers <=> HUB <=> ROUTER (CISCO 800 SERIES) <=> DIAL UP MODEM <=> Internet

When I tried http://www.namadomain.com
it doesn’t worked?….
beside I had been configured my DNS Server, DHCP Server and IIS.?