Hi, Im having problem to perform Exchange 2003 certificate-based authentication, Im working with Ex2003 SP2 with latest updates on Windows Server 2003 R2 with latest SP and updates in a child domain (for this example child1.contoso.com). My TMG server is at the root domain (contoso.com), when Im trying to publish the Exchange 2003 with my SSL certificate listener, everythings good but outside Im getting prompt for Certificate (thats OK), and then pop-up for username/password. I want to avoid the pop-up for username/password, and get into my OWA without any issues, since Im using E attribute at the subjects SSL Certificate for users e-mail address. For example (E = John.Smith@Contoso.com). Is that possible? And if yes, how can I fix this issue please? Please help me! Thanks :)

I haven't done this, but does the UPN on the user accounts match the email address? Exchange doesn't use the email address for login, while it might match, that would be a coincidence if the UPN is configured correctly. Simon. Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

Hello, To meet your requirement, you can use the Windows authentication for OWA access. Thanks, Simon