http://arav.i2p/stuff/article/setting_up_a_mail_server?lang=ru
Copy dovecot.conf file and conf.d directory. We will need dovecot.conf and files from a conf.d directory: 10-auth.conf, 10-mail.conf, 10-ssl.conf, 15-mailboxes.conf, 20-lmtp.conf, 90-sieve.conf, 10-logging.conf, 10-master.conf, 15-lda.conf, 20-managesieve.conf, auth-system.conf.ext.