9. Configure Postfix NULL Client

The local mail server configuration acts as the control client, and all messages are forwarded to the central server for sending

1.postconf-e "relayhost=[mail.example.com]" the server to which the message was routed.
2.postconf-e "inet_interfaces=loopback-omly" mail server listens only for messages on loopback streets
3.postconf-e "MYNETWORKS=127.0.0.0/8 [:: 1]/128" NULL client will be sent from MYNETWORKS=127.0.0.0/8 and [:: 1]/128 mail to the relay host
4.postconf-e "myorigin=example.com" Address rewrite
5.postconf-e "mydestination=" is not sent to the local, while the empty client sends all messages to the repeater
6.postconf-e "local_transport=error:local delivery Disabled" Empty client refuses to receive any messages

7.systemctl enable postfix && systemctl restart Postfix
8.mail-s "Test" [email protected]
Test ok!
.

EOT

9. Configure Postfix NULL Client