Technology and tools

What is SPF?

Sender Policy Framework: a DNS record listing which servers may send email for a domain, so receivers can spot forged senders.

Sender Policy Framework is a DNS TXT record in which a domain lists the mail servers allowed to send email on its behalf. Receiving servers check the connecting server against that list.

SPF checks the envelope sender, not the From address a person sees, and it breaks when mail is forwarded. That is why it is combined with DKIM and DMARC, which ties the checks to the visible From domain.

Where you learn it

See SPF in a real investigation

Our missions put you in front of real logs, domains and forums, with these terms underlined where they appear.

Start learning free