If you want to configure HTTP.SYS, you need a tool call HttpCfg.exe. By default this tool is not installed on either Windows Server 2003 or Windows XP (with SP2 installed). So for Windows Server 2003 you need to go to the "\SUPPORT\TOOLS" folders on the installation CD for the version of Windows Server 2003 that you have installed and install the Support Tools (SUPTOOL.MSI). For Windows XP (With SP 2 installed) you need to download and install the Windows XP Service Pack 2 Support Tools.

Once you have HTTPCfg.exe installed on the machine, you can configure any of the following:

• Add, query and delete SSL certificate meta-information. Such meta-information is maintained by the HTTP API in a metastore, and is used to locate certificates for certificate exchange in HTTPS sessions.
• Add, query and delete namespace reservations. The HTTP API allows administrators to reserve URI namespaces and protect them with Access Control Lists (ACLs), so that only specified HTTP API clients can use them.
• Add, query, and delete Internet Protocol (IP) addresses in the IP Listen List. If this list of addresses is specified, the HTTP API listens only to addresses on the list. Otherwise it listens on all IPs on the machine.

For more details on HTTPCfg.exe, the following link is very useful: http://www.microsoft.com/resources/documentation/WindowsServ/2003/all/techref/en-us/Default.asp?url=/Resources/Documentation/windowsserv/2003/all/techref/en-us/httpcfg.asp

Also, there is some registry keys that you can leverage to configure HTTP.SYS, please see http://support.microsoft.com/default.aspx?scid=kb;[LN];820129