I have two domains (example.com and example.net and I want to allow example.net to send email from foo@example.com

In my SPF I currently have:

v=spf1 a mx ip4: include:spf-a.outlook.com -all

To add the second entry do I add this as ip4: or should I use include:example.net or are neither correct in this situation?

2 Answers 2


Which spf record is that? Example.net? Example.com? The spf record for example.com should contain ip4: Using include would include the whole spf record of the target domain (and fail if there is none), this is probably not what you want. Of course for production ip should not be private ones.

  • This was for example.com - I wasn't sure if I should use the IP or include. Email will never actually come from foo@example.net, all emails will come from the example.net server but will use example.com as the sender address etc
    – bhttoan
    Oct 10, 2014 at 22:25

Either are valid, but use ip4:.

Outlook.com's SPF records spiral down so deep into DNS lookups that you cannot add [m?]any more include: directives without violating SPF's RFC-defined limit. Most SPF validators don't strictly enforce this, but some do and can cause deliverability issues at random.

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