Hi Joelly and thanks for your answer!

About this:

"One last question: since I have to deal with huge mailboxes, if prior to activate replication I do an rsync between the two Dovecot filesystems, does the replication will work?"

Do you think I will reduce the bandwidth usage on the IPsec VPN doing rsync prior to activate replication on Dovecot? Or does the replication needs to do a full sync of the entire mailbox even if the mail dir is already copied on the other end?

And what about the first question: where I can find an example of LDAP userdb to exclude all users from replication and adding one at a time?

Thanks in advance!

Cheers

One last question: since I have to deal with huge mailboxes, if prior to activate replication I do an rsync between the two Dovecot filesystems, does the replication will work?