I can’t find it but Gmail actually had some sort of whitepaper or something once about Gmail-originated SPAM and how it became a huge problem which was partially the reason they started doing phone verification.
The parent’s comment is valid. Any modern email peer is doing domain based reputation which is possible thanks to SPF and DKIM, and if you don’t have those configured you’ll have a bad time. Then it’s the job of the domain owner or email operator (postmaster) to make sure you’re not blasting out SPAM and respond to abuse feedback. If you think about it, this is the only sane way for email to function without preauthentication.
The only major outlier to this is Outlook, which is still doing IP based reputation. And of course a long tail of small server operators that rely on legacy SPAM lists from decade ago and reject only legitimate emails and pass through plenty of Viagra ads.
The parent’s comment is valid. Any modern email peer is doing domain based reputation which is possible thanks to SPF and DKIM, and if you don’t have those configured you’ll have a bad time. Then it’s the job of the domain owner or email operator (postmaster) to make sure you’re not blasting out SPAM and respond to abuse feedback. If you think about it, this is the only sane way for email to function without preauthentication.
The only major outlier to this is Outlook, which is still doing IP based reputation. And of course a long tail of small server operators that rely on legacy SPAM lists from decade ago and reject only legitimate emails and pass through plenty of Viagra ads.