The tag for SPF records is "v=spf1" while Sender ID is using other tags like "spf2.0/pra", "spf2.0/from".
But it defines the new PRA identity to validate, and defines new sender policy record tags that specify whether a policy covers MAIL FROM (called MFROM by Sender ID), PRA, or both. Since it was derived from SPF, Sender ID can also validate the MAIL FROM.
SPF was initiated by Meng Weng Wong of to enable validation of legitimate sources of email for a domain and is now an IETF standard ( RFC 4408).Īn SPF record is a type of Domain Name Service (DNS) record that identifies which mail servers are permitted to send email on behalf of your domain.