Website diagnostics
SPF Checker & Record Check
Use a free SPF checker and record check tool with Web Health. Test SPF syntax, confirm authorized mail servers, detect lookup issues, and help prevent email spoofing.
Understanding Sender Policy Framework (SPF)
SPF is an essential email authentication protocol designed to combat domain spoofing and phishing. By specifying exactly which mail servers are authorized to send messages for your domain, SPF helps receiving mail systems (Gmail, Outlook, Yahoo) verify sender legitimacy.
Common SPF Mechanisms
- v=spf1: Required prefix defining the record as SPF version 1.
- ip4 / ip6: Explicitly authorizes specific IP addresses or CIDR subnets.
- include: Delegates authorization to a third-party service (e.g. _spf.google.com).
- ~all (SoftFail): Advises receivers to accept but mark unauthorized mail.
- -all (HardFail): Directs receivers to reject emails from unauthorized senders.
SPF Optimization Best Practices
- Single SPF Record: Ensure exactly one SPF TXT record exists on your domain root.
- Stay Under 10 Lookups: Audit nested includes to avoid RFC 10 DNS lookup limit errors.
- Combine with DKIM & DMARC: Deploy SPF alongside DKIM signatures and DMARC enforcement.
- Remove Stale Services: Delete legacy email service providers from your include mechanisms.
Frequently Asked Questions
An SPF (Sender Policy Framework) record is a DNS TXT record that publishes an authorized list of mail servers and IP addresses permitted to send email on behalf of your domain name.