How to Troubleshoot SSL in Internet Information Server 4.0

MORE INFORMATION

Key Manager

Key Manager is an application that allows for the installation of Server Certificates for the SMTP and WWW services. The following points are important to remember when you use this application:

• After you perform any operations in Key Manager, commit the changes. This can be done through the Computers menu option or when exiting. If Key Manager is closed without saving changes or if the application is left open, then the creation, deletion, or changes made to a key will not be implemented.
• Unless an installed key is associated with an IP Address and Port (this includes "Any Unassigned"), the key will not be available to the appropriate service.
• After a change is committed in Key Manager, it is necessary to restart the Inetinfo process for proper functionality. To do this, Stop the IIS Admin Service in Control Panel Services, and then restart all appropriate subordinate services, such as the World Wide Web Publishing service.

Microsoft Management Console (MMC)

The properties for a Web site include the following important configuration options:

1. On the Master Properties sheet of Internet Information Server, click the ISAPI Filters tab. There should be a listing for "sspifilt" with the Status showing a green, upward-pointing arrow and a Priority of "HIGH."
2. On the Web site Properties tab, the SSL Port should be set to 443.
3. On the Secure Communications area of the Directory security tab, click to select the "Require secure channel when accessing this resource" check box.

NOTE: If instead of an Edit button being displayed on the Directory Security tab, the button displays "Key Manager," the WWW Service is unaware of a key for SSL. If a key is installed already in Key Manager, see the "Key Manager" section of this document.

Standard SSL Connectivity

If you follow the "Key Manager" and "Microsoft Management Console" sections above, and SSL is not fully functional, see the following:

• If a Web browser displays no error and simply times out, the cause may be one of the following:
  
  
  • A router or firewall on the network is blocking TCP port 443.
  • The Sspifilt.dll ISAPI filter is not loaded properly. See step 1 in the Microsoft Management Console section above.
• If you use Internet Explorer 3.02 and the error "A connection with the server could not be established" occurs, the Root Certificate (signer) of your SSL key in not installed in the browser.
• If Microsoft Proxy Server 2.0 is installed on the Internet Information Server computer, Web Publishing must be enabled. In addition, if Packet Filtering is being used, a packet filter for TCP Port 443 must be added.
• Secure Sockets Layer does not function properly when you implement HOST Headers on a Web site.

The HOST header is packaged in the HTTP request, which is in-turn encrypted in the TCP packet. The TCP packet is sent to a specific IP address and the HTTP request is opened by the first Web site bound to that IP. Because many HOST header Web sites may bound to an IP address, unexpected results may occur.

SSL with Client Certificates

If client authentication is enabled, but not fully functional, see the following:

• The Web server returns a 403.7 Client Certificate required message. This message is a generic error from the Web server; it can indicate several conditions:
  
  
  • There is no Client Certificate installed in the browser.
  • The Client Certificate supplied is not yet valid or is corrupt.
• An empty Client Certificate dialog appears when you access a client authentication Web site, which may indicate one of the following conditions:
  
  
  • There is no Client Certificate installed in the browser.
  • Service Pack 4 is installed. See the following Knowledge Base article for more information:
    

    194788 : Windows NT Service Pack 4 and Client Certificates

NOTE: Due to known issues with the Service Pack 3 version of the Schannel.dll file, it is highly recommended that you apply Service Pack 4 to any server relying on SSL functionality.