Routing all outgoing mails via the outgoing smarthost:
- Ensure the IP address is added as an authorized smarthost (without authentication)
- Ensure the outgoing user has correct limits set matching your traffic volumes
- Update your configuration:
echo ":SMARTHOST:587" > /var/qmail/control/smtproutes
This will override any existing smtp routes. If you do not want this, you can replace the single > with >>.