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I'm very new to all things DNS, yet I am trying to set up some SPF records. So far the SPF Setup Wizard has been immensely helpful, and I think I have things pretty much set; however I'd really like to know what the difference between and is. Is it somewhat redundant to have both? Or do they both do mutually exclusive things? Thanks in advance.

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up vote 7 down vote accepted
  • "include:" includes the settings from another SPF-record (must point to a different name) - it does not actually specify any hosts ifself.

  • "mx:" includes the hosts designated by MX-records for a domain name (same a using "a:" for each of the host names pointed to by the MX-records).

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The 'include' directive allows you to import SPF settings from another zone. Imagine if you are a company that has 5-7 zone. Rather than writing the SPF records each time, you can just write them on one and import to the others.

Hope that helps!

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Helped me! This seems to be a primary use-case (along with "I need to import someone else's SPF") of include. Kind of wish the syntax docs mentioned this more explicitly as a distinguishing reason to use include rather than "a". – jeremyclarke May 11 at 20:16

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