We use qmail + vpopmail + dovecot, limits and alias are in vpopmail mysql database, it has worked ok.
The .qmail-default: | /data/vpopmail/bin/vdelivermail '' bounce-no-mailbox | /var/qmail/bin/preline -f /usr/local/dovecot/libexec/dovecot/deliver -d $EXT@$USER When you send a message to alias works OK. The problem that is happening that is sent to a...@domain.com a...@domain.com he is doubling the email. Come the email that you sent / wrote an email and more with nearly no head, no matter. Searching is very realized that something related to Deliver the dovecot. Can you help us? Tips? Thank you all.