Library

Longer pieces, with the workings left in.

Every piece names its sources. Where we relied on somebody else's estimate, we say it is an estimate.

Aug 16, 2026
Zendesk's SPF record has one entry. A receiver counts six.

Canva sits at nine of a possible ten, and I only know because I wrote a counter that follows the chain the way a receiving server does rather than the way a person reads it.

Authentication
4 min
Aug 16, 2026
I checked seventeen domains for deliverability. Only two were broken.

I expected a mess and did not find one. The interesting results were the two domains that were not clean, and neither failure is the one you would guess.

Deliverability
4 min