SPF (Sender Policy Framework)

A DNS record listing the servers permitted to send email for your domain. Receiving mail servers check it before deciding whether to trust the message.

[01]What It Means

SPF is a single TXT record published in your domain’s DNS. It names every service allowed to send mail on your behalf, usually as a list of includes: your mailbox provider, your CRM, your transactional sender, your outbound tool.

The record ends with a qualifier that tells receivers what to do about anything not listed. ~all means treat it as suspicious, -all means reject it outright, and ?all means take no position, which offers no protection at all.

SPF checks the envelope sender, not the address a human sees in the From field. That distinction matters, because a message can pass SPF and still display someone else’s name.

[02]Why It Matters

Outbound programmes fail quietly when SPF is wrong. Mail is accepted, no bounce arrives, and the messages land in spam where nobody counts them. Every sending tool you add to a go-to-market stack is another sender that has to be authorised, which is why SPF breaks most often during expansion rather than at setup.

[03]Where It Goes Wrong

More than one SPF record on a domain, which invalidates bothExceeding the ten DNS lookup limit as sending tools accumulateLeaving ?all in place, which authorises nothing and protects nothing

[04]Related Terms