SPF & DMARC explained: who may send for a domain?

SPF: the domain’s permission list

SPF (Sender Policy Framework) is a record in the DNS of the sender’s domain - in essence a permission list. It names exactly the server IP addresses that may send e-mail for that domain. When your mailbox receives a mail, NeoMail24 compares the sending server’s IP with this list: listed means legitimate, not listed is a warning sign.

DMARC: the instruction for the case of forgery

DMARC (Domain-based Message Authentication, Reporting and Conformance) builds on SPF and DKIM. It requires that at least one of the two checks passed and that the sender’s domain really matches. And it contains the domain owner’s instruction: what should happen to forged mails - just mark them, put them in quarantine or reject them?

Together they paint the traffic-light picture

Only the trio of SPF, DKIM and DMARC produces a reliable picture. NeoMail24 applies all three checks to every incoming mail and condenses the result into the traffic light: green means "sender verified", yellow means "look closer", red warns of forgery signals. In addition, the spam filter rates the subject, content and links of every message.

Why this matters to you too

You benefit even without a domain of your own: every phishing mail that reaches you is a forgery in the name of someone else’s domain. The more strictly receivers like NeoMail24 evaluate these checks, the less attractive forging becomes for criminals. The traffic light makes the technology visible - without your reading a single header line.

That completes the trio: SPF checks the permission, DKIM the signature, DMARC the policy. NeoMail24 checks all three on every incoming mail - you spot forged senders at a glance.