SPF (Sender Policy Framework) is a way to tell receiving mail servers which systems are allowed to send email on behalf of your domain. It’s set as a DNS record that lists approved senders like your email provider, website, CRM, or invoicing system.
When an email is received, the server checks the sending IP Address against your SPF record. If it matches, it passes. If not, it fails. That’s how it helps catch spoofed emails pretending to be from your domain.
SPF doesn’t verify the content of the email and it doesn’t guarantee delivery. It just answers the question: “Is this server allowed to send for this domain?”
When SPF is working, nothing stands out, emails go through normally. When it’s wrong or missing, you can see issues like messages going to spam, inconsistent delivery, or systems rejecting your email outright.
Common problems include not listing all sending services, having multiple SPF records (which breaks validation), or hitting the DNS lookup limit because the record gets too complex. It also breaks easily when new tools are added and nobody updates the record.
You can check it by sending an email and reviewing the headers. If it says “SPF: PASS,” you’re good. If it says FAIL, SOFTFAIL, or NONE, something’s off.
SPF is one part of the email trust setup, alongside DKIM (which verifies the message itself) and DMARC (which defines what happens when checks fail). Without SPF, your domain is easier to spoof and your emails are less likely to be trusted.