Hi! We deployed Exchange 2003 (front-end and back-end). Our clients use ActiveSync by using their MDAs. They can successfully logon to Exchnage 2003 if they use ONLY and ONLY pre-Windows 2000 logon name. It is like that: HOSTIX\user01_domain.com Actually this user has following account name on our server: User logon name: user01@xxxxxxxxxxx How can we tell Exchange that user can only use user01@xxxxxxxxxx account information if they use ActiveSync. For other Services such as OWA,OMA, RPC over HTTPS, IMAP they can successfully use their logon name in form user01@xxxxxxxxxxx The only problem exists in ActiveSync logon name. Any idea? Cicek