Host headers enable you to assign multiple sites to one IP address on a Web server, without assigning a unique IP address to each Web site or designating non-standard TCP port numbers. Using host headers is the most common way to host multiple Web sites.
The following list outlines the steps to complete, in IIS, to add a host header name or multiple host header names to an IP address. After you complete the following steps, you must then register the host header name or names with the appropriate name resolution system. If your computer is on an intranet, register the host header name or names with the intranet's name resolution system. If your computer is on the Internet, register the host header name or names with the Domain Name System (DNS), which is administered by InterNic.
Add a Web site to the Web server.
Edit the Web site binding and add a host header name, or create a new binding with a host header name.
Add additional bindings with the same IP address and port number, but different host headers if you want to have additional sites assigned to one IP address.