Use o imapsync .
imapsync --buffersize 81920000 --nosyncacls --subscribe --syncinternaldates --fast --host1 server.zimbra.tld --user1 [email protected] --password1 badasspass --tls1 --host2 server.dovecot.tld --user2 [email protected] --password2 lalala --tls2
trecho do site
The purpose of imapsync is to migrate IMAP accounts or to backup IMAP accounts. IMAP is one of the three current standard protocols to access mailboxes, the two other are POP3 and HTTP with webmails (often tied to an IMAP server).