Messages to our clients are often rejected when the correspondant’s domain fails to include a SPF record. When email transmission via Simple Mail Transfer Protocol (SMTP) was designed, it provided for no real verification of sender. Email authentication is a necessary first step towards identifying the origin of messages and thereby establishing trust between mail servers.
Sender Policy Framework (SPF) is a simple email-validation system designed to detect email spoofing by providing a mechanism to allow receiving mail exchangers to check that incoming mail from a domain comes from a host authorized by that domain’s administrators. The list of authorized sending hosts for a domain is published in the Domain Name System (DNS) records for that domain in the form of a specially formatted TXT record. Email spam and phishing often use forged “from” addresses. Publishing and checking SPF records is a simple and effective approach to establishing trustworthy communications between correspondants.
Establishing a SPF record is a simple, elegant way to establish trust between mail servers. There is no reason not to establish a SPF record today!