SPF Record

What This Check Does

The SPF Record check verifies that a TXT record containing "v=spf1" exists for your domain root. SPF (Sender Policy Framework) is a fundamental email authentication mechanism that specifies which mail servers are authorized to send email on behalf of your domain.

DNS Spy queries your domain's TXT records and looks for a valid SPF record. If no SPF record is found, this check fails.

Why It Matters

Without an SPF record, any mail server in the world can send emails that claim to be from your domain, and receiving servers have no way to verify the claim. This makes your domain a prime target for phishing and spoofing attacks. Attackers can send fraudulent emails appearing to come from your domain to trick recipients into revealing sensitive information.

SPF is the first layer of email authentication, working alongside DKIM and DMARC to create a comprehensive email security framework. Without SPF, your DMARC policy cannot function effectively, and your email deliverability may suffer as anti-spam systems treat unauthenticated domains with suspicion.

NIST SP 800-81, Section 6, emphasizes the importance of email authentication, with SPF being a foundational requirement.

NIST SP 800-81 Compliance

Section 6 of the NIST Secure DNS Deployment Guide addresses email security and specifically recommends implementing SPF records. DNS Spy continuously monitors for the presence and validity of your SPF record, ensuring compliance with NIST email authentication guidelines.

Good vs. Bad Configuration

Bad Configuration

No TXT record containing 'v=spf1' exists for example.com. Any server can send email as your domain with no authentication check.

Good Configuration

example.com TXT "v=spf1 include:_spf.google.com include:sendgrid.net -all" — Authorizes Google and SendGrid to send email, and rejects (-all) all other sources.

How DNS Spy Monitors This

DNS Spy queries your domain's TXT records during each monitoring cycle, checking for a valid SPF record. If the SPF record is missing or removed, an alert is sent immediately. DNS Spy also monitors for changes to your SPF record, ensuring authorized senders remain properly configured.