On 8.03.2019 18:01, Wietse Venema wrote:
Ozy Mate:
Dear Friends,
I have signed up with a 3rd party smtp server as relay host. This server
needs the following lines in the main.cf of our server instead of relayhost
direction:
smtp_sender_dependent_authentication = yes
sender_dependent_relayhost_maps = hash:/etc/postfix/sender_relay
smtp_sasl_auth_enable = yes
smtp_sasl_security_options = noanonymous
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
This is working fine. However, all the senders/domains not listed in
sender_relay file are still able to send emails directly from our email
server. How can I block this? I mean sender not listed in sender_relay file
should not be able to send any email from our Postfix server.
That's easy enough, use sender_dependent_default_transport_maps,
and a default transport that returns mail as undeliverable.
/etc/postfix/main.cf:
sender_dependent_default_transport_maps = hash:/etc/postfix/sender_relay
default_transport = error:5.7.1 sender is not authorized
/etc/postfix/sender_relay:
# sender transport:nexthop
us...@example.com smtp:relay-for-user-1.example
us...@example.com smtp:relay-for-user-2.example
Wietse
Easy for you, Wietse, not for me. I try and report back.
Thank you very much.
