XCLN: Windows 95 and Windows 98 Instant Messaging Client Authentication From Separate Domain

When a user uses a computer that is running Windows 95 or Windows 98 to attempt to log on to an Instant Messaging server in a different domain by using NTLM authentication, authentication problems may occur. The user may be prompted for logon credentials multiple times or the user may automatically be logged off.

To resolve this problem, implement the updated version of the system dynamic-link library (DLL), Secur32.dll, that is available for download from the following Microsoft Web sites. Click on the URL for your operating system:

For Windows 95: For Windows 98:

To work around this problem, disable NTLM authentication on the Instant Messaging server, and use digest authentication instead:

1. Open the Internet Information Services Microsoft Management Console (MMC) snap-in.
2. Under the appropriate Web site, open the properties of the Instmsg virtual root.
3. Click the Directory Security tab, and then click Edit under Anonymous Access and Authentication Control.
4. In the Authentication Methods dialog box, click to clear the Integrated Windows authentication check box.

Microsoft has confirmed that this is a problem in Microsoft Windows 95 and Microsoft Windows 98.