DMARCIAN: Concluding the Experiment: SPF Flattening

DMARCIAN just released a engaging article:

“SPF Flattening” was invented by dmarcian as part of the initial release of the SPF Surveyor. For many years the functionality was flagged as “experimental.” Today, we’re concluding the experiment and sharing what we’ve learned. Sender Policy Framework (SPF) Background Email operators use SPF to identify themselves and their infrastructure when sending email across the internet. SPF was originally created by email operators around 2000 in response to Joe Job Attacks. At that time, spammers were making victims out of legitimate email operators by pretending to be them while sending spam. Legitimate operators were blamed for sending spam simply because there was no easy way to identify email operators and their infrastructure. Email operators publish SPF records to describe their email infrastructure. These records are specially formatted strings of text that live in the DNS. When receiving email, an email server looks at the domain of the sending operator’s email

Continued here: Concluding the Experiment: SPF Flattening

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