Configuration Overview
Dovecot Backend
Dovecot can be configured for use in "backend" mode on a single server. In this mode, Dovecot is responsible for reading and writing mails to storage and handling all of the email protocols.
Dovecot Proxy
Dovecot can be configured for use in "proxy" mode on a single server. In this mode, Dovecot is responsible for proxying incoming email protocols to remote hosts.
See proxy passdb.