An SPF record (Sender Policy Framework) is a txt record you add to your DNS to restrict where emails using your domain can be sent from. It helps prevent spammers from sending fake emails that look like they came from your business.

SPF records are an advanced level topic, so I won't explain further here.

This post is aimed at people trying to troubleshoot and create an SPF record.

Getting things right can be complex when you have multiple email servers and emails being forwarded. These are some tools I used recently that might help others (and my future self)

Online tools I use

  • SPF Wizard
    • Assists in creating a valid SPF record by breaking each part into separate fields you can fill in
  • SPF Testing Tools
    • Lookup, check syntax is valid and especially helpful Test an SPF record
    • Test if an email from a certain IP and email address will succeed. Great to troubleshoot emails being blocked when they shouldn't be
  • MX Toolbox - Super Toolbox
    • A wide range of tools to lookup almost anything for a domain
  • Find an IP Address
    • Find the IP for a domain. Lookup the IP of MX servers etc
  • CIDR to IPv4 Conversion
    • Convert an IP range to CIDR

With the above you should be able to find what you need to create and test a complex email setup.