Hi, I have upgrade my Exchange 2000 Front-End Server to Exchange 2003 . My BackEnd still running Exchange 2000 Enterprise. After the upgrade, I can't access to the OWA in the Exchange 2003 Front-End Server. I always receive the following error messages as shown below. Event Type: Warning Event Source: EXPROX Event Category: None Event ID: 1000 Computer: FrontEnd-Exch Description: Microsoft Exchange Server has detected that NTLM-based authentication is presently being used between this server and server 'BackEnd-Exch'. NTLM is still a secure authentication mechanism and protects users' credentials. However, this indicates that there may be a configuration issue preventing the use of Kerberos authentication. If this condition persists, please verify that server 'BackExch' is properly configured to use Kerberos authentication. After applying any changes it may be necessary to restart Internet Information Services on both the front-end and back-end servers. Regards Wystan
