SPF publishes which mail servers are authorised to send for a domain used in email delivery. Plan it around all legitimate sending services and maintain one SPF policy record per hostname. Do not add a second competing SPF record whenever you add a new service.
Before you begin
- List all legitimate sending services.
- Avoid duplicate SPF policies at one hostname.
- Test each important sender.
List every service that sends for the business
Start with the mailbox provider, then consider your website forms, invoice system, booking tools and newsletters. Some services use their own sending domain; others need authorisation for yours. Ask each provider what it requires for your particular setup.
This inventory prevents an easy mistake: configuring only the staff mailbox and forgetting the service that sends customer receipts. Keep the business purpose and responsible person beside each sender so obsolete services can be reviewed later.
Inspect the existing policy before editing
SPF is commonly published as a TXT record. Read the current record before replacing it, and keep a copy. Adding a second TXT record beginning with the SPF version marker is not the normal way to combine another provider’s instructions.
SPF also has limits on DNS lookups. A long list of provider includes can become invalid even if each looks reasonable on its own. If the combined policy is unclear, ask the email administrator or provider to validate the complete record rather than assembling guesses.
Make a controlled update
Use the actual sending providers’ current instructions.
- Confirm the active DNS host and exact hostname being authenticated.
- Record the existing SPF policy.
- Account for all legitimate senders in one valid policy for that hostname.
- Check syntax and lookup limits.
- Test messages from each important sending service.
Do not treat SPF as the whole email setup
SPF does not create inboxes or replace MX routing. It also does not guarantee that a message reaches the inbox. DKIM, DMARC, message content and recipient systems are separate parts of delivery and trust.
If you change nameservers, preserve the SPF policy in the new active zone. If you change a sending service, review the policy deliberately. Keeping the domain registration and renewal current is the foundation, while the chosen email provider supplies the mail service itself.
Prepared with AI-assisted drafting and illustration, then checked against the linked sources and NameUK’s current service. The artwork is conceptual; setup values must come from your own provider.
Further readingGoogle Workspace: set up SPF ↗IETF RFC 7208: SPF evaluation and DNS lookup limits ↗NameUK registration and renewal prices ↗Extension rules and provider processes can change. Check the current registrar instructions before a registration, transfer or renewal.
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