Mail relay for FreeBSD

Disable Sendmail

Stop the services in /etc/rc.conf

sendmail_enable="NO"
sendmail_submit_enable="NO"
sendmail_outbound_enable="NO"
sendmail_msp_queue_enable="NO"

Stop Sendmail

Stop the service

service sendmail stop

Install OpenSMTPD

Install the package from ports

pkg install opensmtpd

Configure SMTPD

Add the relay credentials to /etc/mail/secrets

myrelay webmaster@example.com:xxx-password-xxx

/usr/local/etc/mail/smtpd.conf

listen on socket
listen on lo0

table aliases file:/etc/mail/aliases
table secrets file:/etc/mail/secrets

action "local" mbox alias <aliases>
action "relay" relay host smtp+tls://myrelay@smtp.mailgun.org:587 auth <secrets>

match for local action "local"
match for any action "relay"

Enable SMTPD in /etc/rc.conf

smtpd_enable="YES"

Edit /etc/mail/aliases

root: root@onetwoseven.one

And run:

newaliases

Configure the system to use smtpd in /etc/mail/mailer.conf

sendmail        /usr/local/sbin/smtpctl
send-mail       /usr/local/sbin/smtpctl
mailq           /usr/local/sbin/smtpctl
makemap         /usr/local/sbin/smtpctl
newaliases      /usr/local/sbin/smtpctl
hoststat        /usr/bin/true
purgestat       /usr/bin/true

Add a symlink:

ln -sf /usr/local/sbin/smtpctl /usr/local/sbin/sendmail