я не понял, а в чём проблема - то?

postconf -e 'smtpd_sasl_type = dovecot'
postconf -e 'smtpd_sasl_path = private/auth'
postconf -e 'smtpd_sasl_local_domain ='
postconf -e 'smtpd_sasl_security_options = noanonymous'
postconf -e 'broken_sasl_auth_clients = yes'
postconf -e 'smtpd_sasl_auth_enable = yes'
postconf -e 'smtpd_recipient_restrictions = permit_sasl_authenticated,permit_mynetworks,reject_unauth_destination'

postconf -e 'smtp_tls_security_level = may'
postconf -e 'smtpd_tls_security_level = may'
postconf -e 'smtp_tls_note_starttls_offer = yes'
postconf -e 'smtpd_tls_loglevel = 1'
postconf -e 'smtpd_tls_received_header = yes'

postconf -e 'smtpd_helo_required = yes'
postconf -e 'smtpd_helo_restrictions = reject_non_fqdn_helo_hostname,reject_invalid_helo_hostname,reject_unknown_helo_hostnam
e'

server_host = ldap://10.0.0.1
search_base = dc=head,dc=somewhat,dc=ru
query_filter = (&(objectClass=posixGroup)(mail=%s))
result_attribute = memberUid
result_format = %u@mail.somewhat.ru

server_host = ldap://10.0.0.1
search_base = dc=head,dc=somewhat,dc=ru
query_filter = (&(objectClass=posixAccount)(mail=%s))
result_attribute = uid