Opendmarc

Start service manually:

/usr/sbin/opendmarc -p local:/var/spool/postfix/var/run/opendmarc/opendmarc.sock -u opendmarc -P /var/spool/postfix/var/run/opendmarc/opendmarc.pid
/usr/sbin/opendmarc -p local:/var/spool/postfix/var/run/opendmarc/opendmarc.sock -c /etc/opendmarc.conf -u opendmarc -P /var/spool/postfix/var/run/opendmarc/opendmarc.pid

Docs:

• https://www.howtoforge.com/community/threads/opendmarc-on-stretch.77500/
• https://p5r.uk/blog/2017/dmarc-with-postfix.html
• https://www.skelleton.net/2015/03/21/how-to-eliminate-spam-and-protect-your-name-with-dmarc/
• https://petermolnar.net/howto-spf-dkim-dmarc-postfix/#fn6