Not sure if I'm supposed to do this, but as I like to document things that I've found hard, I've put up a tutorial for getting dkim working with opensmtpd. The link is below in case it might help someone now or in the future:
https://simonh.uk/2021/06/23/get-dkim-working-with-opensmtpd/ -- Web: https://simonh.uk Email: m...@simonh.uk
