[vgb2k18]

> That's it. Now your mailer should work.

Work... technically... yes. If the definition of 'works' is: "I press send and sometimes my email reaches it's destination".

The spirit of the article IMO implies a definition akin to "I press send and my email reaches it's destination. And... my emails have some protection against spoofing attacks".

So in the spirit of the article, I would recommend your 1-liner takes a small yet significant change:

v=spf1 include:example.com -all

Now... let's talk about biggest barrier to entry for n00bs (myself included) in the self-hosted email game: non-blacklisted ip-address space. And blacklist here refers not just to public lists (SPAMHAUS etc) but private ones too (e.g., outlook).