installing Dovecot on MacOsX using HomeBrew

Install

brew install dovecot
sudo vim /Library/LaunchDaemons/homebrew.mxcl.dovecot.plist

Configure

sudo cp /usr/local/etc/dovecot/dovecot-example.conf  /usr/local/etc/dovecot/dovecot.conf
sudo vim /usr/local/etc/dovecot/dovecot.conf

Mine reads (it's just meant to access imap files from the local mail server and not to serve outside the localhost):

disable_plaintext_auth = no
mail_location = maildir:~/Maildir
ssl = no
default_login_user = lup
passdb {
  args = login
  driver = pam
}
protocols = imap
service auth {
  user = root
}
service imap-login {
  inet_listener imap {
    address = 127.0.0.1
    port = 10143
  }
  inet_listener imaps {
    address = 127.0.0.1
    port = 10943
  }
}
userdb {
  driver = passwd
}

Reload

sudo launchctl unload homebrew.mxcl.dovecot.plist
sudo launchctl load homebrew.mxcl.dovecot.plist

It does not work on the first try... so read documentation

less /usr/local/share/doc/dovecot/documentation.txt
less /usr/local/share/doc/dovecot/auth-protocol.txt
less /usr/local/share/doc/dovecot/wiki/PasswordDatabase.PAM.txt

Authentification

ls -l /etc/pam.d/
sudo vim /etc/pam.d/dovecot

with /etc/pam.d/dovecot being

auth       required       pam_permit.so
account    required       pam_permit.so
password   required       pam_deny.so
session    required       pam_uwtmp.so