I assume, you are using IMAP. Search the forums for imapsync.
my mail server has user mails and mail directories stored in "/home/username" and the authentication is through /etc/password. it runs sendmail as mta and i use squirel mail as webclient .
i am planing to migrate to zimbra 4.0 and i dont have any idea how i should move about 1500 users and there mail . i dont understand how mails are stored in zimbra , as i have figured out it is stored in /opt/zimbra/store ..
can any one help me how should i migrate my mail server.
please do it in step by step maner