I don't need to receive emails from anybody.
I just want to be able to to send emails from no-reply@mydomain.com for password resets, email address verifications, things like that.
And I would like to at least make an attempt to have the emails I send pass through a basic spam filter. So I assume at the very least I need to setup DKIM and SPF records.
Is it as simple as following https://wiki.debian.org/Postfix and https://wiki.debian.org/opendkim ?
(That is the route I am taking right now, will report back here what I find out in a few hours!)
Is there a reason why you're not choosing an email provider? there are very cheap ones out there. What you're trying to do is normally called "transactional" email normally and there are a lot of providers who specialize in that.
Then be sure to set a DMARC DNS record that advises recipients to require DKIM. Downside is your mail will bounce when you mess up DKIM, upside is you'll get somewhat clear feedback.
I used dkimpy, pretty simple: https://russell.ballestrini.net/quickstart-to-dkim-sign-emai...
Going to try again tomorrow :S
All email is perl.