docker postfix opendkim
easy to use.
DOMAIN_NAME=youdomain.com
DKIMDOMAIN=email
docker run -it --rm -e DOMAIN_NAME=$DOMAIN_NAME -e SELECTOR_NAME=$DKIMDOMAIN -e DKIMDOMAIN=$DKIMDOMAIN --name sendmail-dkim --hostname $DOMAIN_NAME -v dkimkey:/etc/dkimkeys -p 25:25 kasen/postfix-server
look docker run logs, set DKIM / SPF record
DKIMDOMAIN
._domainkey.DOMAIN_NAME
TXT v=DKIM1; h=sha256; k=rsa; t=s; p=
selfspf.DOMAIN_NAME
A your IPv4
selfspf.DOMAIN_NAME
AAAA your IPv6
DOMAIN_NAME
TXT selfspf.DOMAIN_NAME TXT v=spf1 include:selfspf.DOMAIN_NAME ~all
in docker,
sendemail -o message-charset=utf-8 -t [email protected] -f test@$DOMAIN_NAME -m "from test@$DOMAIN_NAME test email." -u 'test email : $(date)'