XCCC: Cannot Log On to Outlook Web Access with Secure Sockets Layer from Macintosh Computer (322261)

SYMPTOMS

When all the following conditions are true

you use Outlook Web Access (OWA)

-and-
you have Secure Sockets Layer (SSL) turned on

-and-
you try to gain access to a computer running Exchange 2000 Server

you may receive the following error message:

The identity certificate uses an unknown signature algorithm.

CAUSE

This behavior may occur if both of the following conditions are true:

You use Microsoft Internet Explorer 4.5 for the Macintosh on an Apple Macintosh computer.

-and-
The certificate is issued by Microsoft Certificate Server.

RESOLUTION

To resolve this behavior, install Microsoft Internet Explorer 5 Macintosh Edition. To download this program, visit the following Microsoft Web site:

http://www.microsoft.com/mac/download/

WORKAROUND

To work around this behavior, verify the following:

The bit length of the certificate
The certificate bit length that the client supports
The type of certificate that you are using

If you have Internet Explorer 4.5 for the Macintosh installed, you may have to adjust these settings.

When you use the Certificate Wizard in Microsoft Internet Information Services (IIS), the default certificate uses Secure Hash Algorithm (SHA) encryption with either a 512-bit or a 1024-bit key. However, the Macintosh computer will reject any certificate that uses these default SHA values.

However, you can create a Server Gated Cryptography certificate for export. This uses the Message Digest 5 (MD5) Rivest, Shamir, & Adleman (RSA) signature algorithm. Internet Explorer 4.5 for the Macintosh only supports this method for signing certificates.

MORE INFORMATION

For additional information, click the article numbers below to view the articles in the Microsoft Knowledge Base:

319574 HOW TO: Use Certificates with Virtual Servers in Exchange 2000 Server

320878 HOW TO: Manage Certificates in Windows 2000

The third-party products that are discussed in this article are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, regarding the performance or reliability of these products.