Each computer on the Internet has a unique address (the IP address). An IP address is in the form of four period-delimited octets consisting of up to 12 numerals—such as 172.16.16.189. Information is transmitted on the Internet in data packets. Each packet is addressed to a specific computer's IP address.
Because IP addresses are difficult to remember, the Domain Name System (DNS) was created for the Internet to pair a specific IP address, such as 172.16.16.189, with a "friendly" domain name, such as microsoft.com. When you use a domain name in an Internet browser, the browser first must contact a DNS server to resolve the domain name to an IP address, then contact the computer with that address.
This has two implications for your server running Internet Information Server (IIS server):
To establish a World Wide Web (WWW) server, you need a permanent IP address. To connect a TCP/IP network to the Internet, you need a valid IP address for each computer or device you want to be accessible from the Internet.
You must use a domain name if you want Internet users to be able to reach your Internet server or servers by the friendly domain name, such as microsoft.com. Both a registered domain name and an IP address are required for your Internet service to be seen and used by others on the Internet.
Most Internet service providers assign your IP addresses and can also register your domain names. Contact the Internet Network Information Center (InterNIC) or your ISP for more information about DNS registration.
To contact the InterNIC to register domain names and obtain IP addresses, connect to the Internet address http://internic.net.
If you must apply for your own domain name or IP addresses, you must have a good understanding of DNS and of TCP/IP networking. For more information about DNS and TCP/IP networking, see the Windows NT Server Networking Supplement and Windows NT Server Networking Guide.