Understanding SPF, DKIM, and DMARC: A Simple Guide

I manage IT at a mid-size business. At least once a month, I get asked to release some incoming email from quarantine that got sent there because the sender's SPF record is wrong or outdated and doesn't include all the email services they actually use. (What this really tells me is how many small businesses are out there running with no in-house IT expertise or support of any kind.)

I don't do whitelisting. Instead, I always reach out and offer to help the other party correct their SPF record.

It happens often enough that I wrote a script in Racket that will generate the email for me and paste it into the clipboard [1]. The email tells them exactly what they need to change, and links to docs from their current email provider (so they don't have to trust me about edits to their DNS).

[1]: https://gist.github.com/otherjoel/6b8bf02f6db6e0c47ba6bca72e...

Cool stuff! BTW, what's up with the license?

Including the whole license in the gist was probably overkill, but I particularly like Blue Oak for permissive licensing and would like to see it more widely used.

https://writing.kemitchell.com/2019/03/09/Deprecation-Notice...

> If anyone notifies you in writing that you have not complied with [Notices](#notices), you can keep your license by taking all practical steps to comply within 30 days after the notice. If you do not do so, your license ends immediately.

I'm not sure I like it. Like, what if the notification of notice was incorrect? You lose your license anyway?

By default under most open source licenses, particularly permissive ones, violating the terms even by accident ends your license instantly, with no notice whatsoever.

Including a fair, common sense path to forgiveness severely limits legal risk for users, and is one of the things I like about the Blue Oak license.