I am facing a problem as follows: - I have a mailbox "d12@domain.com" on an exchange server. I have created an email alias (secondary email) for this mailbox as d12_d55@domain.com. Now I am sending out an email, programmatically, with the reply-to email header field set to "d12_d55@domain.com". When I download the email sent, to MS Outlook 2000 or higher, the mail seems to be perfect with everything in place. When I click REPLY, I expect to see the id "d12_d55@domain.com" in the TO field. But outlook, for some reason, changes this to "d12@domain.com". When I download the same email to some other machine MS outlook, things behaved as I had expected i.e I got "d12_d55@domain.com" in the TO field. I suspect that there is some MS Outlook setting that is controlling this behvaiour but I have no clue. Could someone throw some light on this and help me understand what is happening and how to control this behaviour? Thanks in advance !!

I'd guess that the one that's changing is set up for exchange (outlook thinks it's smarter than you and if it finds that e-mail to be a "secondary" alias for an exchange box will flip it to the "primary" e-mail address for that mailbox instead) And the one that's not is set up as a POP3 mailbox (outlook can't query alternative e-mail aliases via pop3) The most common work around the "POP3 Hack" can be found here: http://www.arrowmail.co.uk/howto/sendas.aspx It basically involves this: 1. setting up an additional "pop3" account in outlook for each alias you want to be able to use 2. setting the "Incoming mail server" to something fake for those "fake" accounts 3. going into outlook send/receive settings and telling it not to check for incoming mail for those accounts.