Definition

SPF (Sender Policy Framework) is a DNS TXT record that lists which mail servers are authorized to send email on behalf of your domain — helping receivers detect spoofed messages.

Detailed Explanation

When a receiving server gets email from you@yourdomain.com, it checks DNS for an SPF record. If the sending server’s IP is not listed, the message may fail SPF authentication and land in spam.

Example record:

v=spf1 include:_spf.google.com include:servers.mcsv.net ~all
  • include: authorizes third-party senders (Google Workspace, Mailchimp)
  • ~all = soft fail for unauthorized senders
  • -all = hard fail (use when confident)

Limit: maximum 10 DNS lookups in SPF chain.

Nepal Context

Nepali businesses sending bulk email from shared cPanel hosting often fail SPF when using an ESP — fix by adding the ESP’s include to SPF, not sending marketing mail from cPanel directly.

Practical Examples

  • A company using Google Workspace and Mailchimp publishes v=spf1 include:_spf.google.com include:servers.mcsv.net ~all.
  • A business adds a second SPF record for a new tool instead of editing the first, and both start failing.

How to Check It

  1. Look up your SPF record with an online SPF checker, which also counts DNS lookups.
  2. Send a test email to Gmail, open Show original, and confirm SPF: PASS.
  3. Re-check whenever you add a new sending service, such as a CRM or helpdesk.

Key Takeaways

  • One SPF TXT record per domain
  • Authorize every service that sends on your behalf
  • Verify with MXToolbox or mail-tester.com

Common Mistakes

  1. Multiple SPF records (only one allowed)
  2. Exceeding 10 DNS lookups
  3. Forgetting to update SPF when switching ESPs