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by tipalink 2201 days ago
If I were to guess, I'd say the same way adblockers work on browsers: blacklisting domains. Sendgrid was given as an example. They could also block using image size (1px) or location (end of message body).

That being said, I see your point. It's a game of Whack-a-Mole. What's to stop businesses from setting up a cname record on their domain to Sendgrid, for example?

1 comments

The next whack-a-mole move, inspect CNAMEs to see if they reference blocklisted domains