How to configure OpenSMTPD with Amazon SES?

Question

Amazon has instructions for postfix and sendmail, but not OpenSMTPD, so adding them here.

Answer 1

Tested with OpenBSD 5.8

1. Verify your domain and a sender in AWS SES console. Save your SMTP Settings.

2. Set up the SMTP authentication details in the mail secrets database (replacing $smtpUsername:$smtpPassword with the values from step 1)

   # touch /etc/mail/secrets
   # chmod 640 /etc/mail/secrets
   # chown root:_smtpd /etc/mail/secrets
   # echo "ses $smtpUsername:$smtpPassword" >> /etc/mail/secrets
   # makemap /etc/mail/secrets
   

3. Configure OpenSMTPD:

   # nano /etc/mail/smtpd.conf
   
   listen on lo0
   table aliases db:/etc/mail/aliases.db
   table secrets db:/etc/mail/secrets.db
   accept for local alias <aliases> deliver to mbox
   accept from local for any relay via tls+auth://ses@email-smtp.us-east-1.amazonaws.com auth <secrets>
   

4. Restart OpenSMTPD:

   # rcctl restart smtpd
   

5. Test it:

   # sendmail -v -f verified-sender@verified-domain.com to@example.com
   Subject: test subject
   
   test body
   ^D
   

Errors?

watch your line-breaks in smtpd.conf

# smtpd -n to check for syntax errors in smtpd.conf

Try port 587 if your machine is blocking port 25 (add :587 to end of aws url in smtpd.conf)