Background: All users using POP/SMTP account to send and receive email via ISP.One user has 4 different email addresses because there are 3 different brand productions. The main email account is user@company.com, others are user@a.com, user@b.com, user@c.com. When someone sent an email to user@a.com, use can reply by using user@a.com. Project: We plan to use Exchange 2003 instead of POP/SMTP Process: Installed first new Exchange 2003 in test lab. Setup main email account user@company.com for user, deployed other 3 email address under RECIPIENT POLICIES, added other 3 email addresses under user account in AD, configured Outlook 2003 users email account by using Exchange Server. This user can send and receive by using 4 different email addresses. Problem: When someone sent an email to user@a.com, Outlook only show users name, not email address, user dont know which email address the guy sent to. How can we solve this problem by using Exchange 2003. Thanks, Rob

you need to use mutiple AD accounts or a mix of pop3 and exchange server. there are also 3rd party solutions here, but microsoft doesn't easily support what you are trying to do.

BTW, Outlook and Exchange 2010 solve this problem.