dovecot.conf

# (...)
auth default {
  mechanisms = plain login
  passdb ldap {
    args = /etc/dovecot/dovecot-ldap.conf
  }
 
  # Immediately when checking password.
  userdb prefetch {
  }
 
  # For the SMTP (Postfix/Exim)
  socket listen {
    client {
      path = /var/run/dovecot/auth-client
      group = sasl
      mode = 0660
    }
  }
}
# (...)

The Dovecot 2.x configuration is similar, only distributed in separate files, see the 10-auth.conf (included at the end), auth-ldap.conf.ext, 10-master.conf (instead of “listen socket” will “unix_listener ').

dovecot-ldap.conf

uris = ldapi://
dn = uid=dovecot,ou=System,dc=example,dc=com
dnpass = haslo
auth_bind = yes
ldap_version = 3
base = dc=example,dc=com
scope = subtree
pass_attrs = uid=user,userPassword=password,homeDirectory=userdb_home,uidNumber=userdb_uid,gidNumber=userdb_gid