Email and Domain Security – PwnDefend

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Ok, this is a topic I’ve looked at for years, my views have been built up based on a range of things from the theory, the reality of what I find/see and the incidents I respond to and hear about.

I’ve used Claude largely for this because it’s meant as a quick snapshot in time and a high level thematic view. SPF, DMARC, MTA-STS and DNSSEC (and DNS/Domain management in general) are complex topics and there’s lots of nuance in things.

That said, who wants to see what ‘scanning’ 1 million domains looks like? Let’s take a look at what Claude has come up with:

A million domains

The following is a report generated by Claude using Opus 4.8:

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