Error occurs during SSL connection (207523)

The information in this article applies to:

Microsoft Internet Information Server 4.0
Microsoft Internet Explorer Plus 4.0

This article was previously published under Q207523

We strongly recommend that all users upgrade to Microsoft Internet Information Services (IIS) version 6.0 running on Microsoft Windows Server 2003. IIS 6.0 significantly increases Web infrastructure security. For more information about IIS security-related topics, visit the following Microsoft Web site:

http://www.microsoft.com/technet/security/prodtech/IIS.mspx

SYMPTOMS

When you attempt to connect to an IIS Web site using an SSL connection, one of the following symptoms occurs, depending on the browser being used:

In Internet Explorer, the following error message occurs:

Internet Explorer could not open the Internet site: <URL>
The data area passed to a system call is too small.

Netscape Communicator stops responding when you attempt to make the connection.

CAUSE

The browser is trying to use a 128-bit session key, but the Web server is set up to use a 40-bit key.

RESOLUTION

Note Due to export restrictions, the 128-bit key strength encryption feature is available only in the United States and Canada.

To resolve this problem, install the 128-bit version of the latest Windows NT 4.0 Service Pack (SP). This will enable the Web server to create 128-bit connections.

Installing the 128-bit version of the Windows NT SP updates the Schannel.dll file, which is used by IIS to create SSL connections.

MORE INFORMATION

For more information about setting encryption strength, copy the following URL to your browser:

http://localhost/iishelp/iis/htm/core/iistesc.htm

For information on how to determine the security strength that IIS is using, see the following article in the Microsoft Knowledge Base:

184311 Remote key request generation affected by Schannel.dll

Modification Type:	Major	Last Reviewed:	6/30/2006
Keywords:	kbpending kbprb KB207523