You can configure your Web sites and FTP sites to grant or deny specific computers, groups of computers, or domains access to Web sites, FTP sites, directories, or files. For example, if your intranet server is connected to the Internet, you can prevent Internet users from accessing your server by granting access only to members of your intranet, and explicitly denying access to outside users.

Note
IP address restrictions apply only to IPv4 addresses.

Note
In Windows 2003 Server Service Pack 1 (SP1), HTTP.sys will not cache content from a Web site with restricted IP addresses. In this case, you might consider using Internet Protocol Security (IPSec) instead of IP address restriction. For more information about IPSec, see Creating an IPsec Policy to Restrict Ports.