postfix-mta-sts.service

[Unit]
Description=Postfix MTA STS daemon
After=syslog.target network.target

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/bin/systemctl start postfix-mta-sts-daemon@main.service
ExecReload=/bin/systemctl start postfix-mta-sts-daemon@backup.service ; \
/bin/systemctl restart postfix-mta-sts-daemon@main.service ; \
/bin/systemctl stop postfix-mta-sts-daemon@backup.service
ExecStop=/bin/systemctl stop postfix-mta-sts-daemon@main.service

[Install]
WantedBy=multi-user.target