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We have recently started using Office 365 for our email, which requires us to add a DNS TXT record with the value v=spf1 include:spf.protection.outlook.com -all. We already have an SPF record with the value v=spf1 include:spf.mandrillapp.com ?all for Mandrill, an SMTP sender we also use.

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My concern is this might cause some conflict. Is my concern valid or will be be fine with these two SPF records?

Swisher Sweet
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1 Answers1

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You can only have one SPF record (https://www.rfc-editor.org/rfc/rfc4408#section-3.1.2).
You need to combine them like so:

v=spf1 include:spf.mandrillapp.com include:spf.protection.outlook.com -all

or

v=spf1 include:spf.mandrillapp.com include:spf.protection.outlook.com ?all
Community
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faker
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  • I'm in exactly the same position here... of implementing line 1 or line 2... whats the difference between -all and ?all – Adrian Salazar Dec 26 '14 at 10:53
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    @AdrianSalazar `-all`: mails sent from hosts not specifically allowed are not permitted to send mails. `?all`: means any not specified host is neutral and nothing can be said about the validity of it. In practice it is not sent to spam. `?all` renders the SPF record almost useless. However some 3rd party provides want you to use it because they change IPs often and don't want that to cause problems. – faker Dec 26 '14 at 11:10
  • "You can only have one SPF record." That is clearer than the message I got: " Office 365 ondersteunt slechts één SPF-record" (Office365 only supports 1 SPF-record". It suggested (the way I've read it) like other parties support multiple SPF records, but Office365 doesn't. But as I read your post it's normal just to support 1 SPF record. – Michel Jul 18 '16 at 08:12
  • Indeed, each recipient service has a bit of room in the SPF spec in how they want to handle hardfail, softfail, etc. if Office 365 receives a message, it will only perform one SPF lookup. It also has a configurable option on how to handle SPF hardfail. – blaughw Sep 16 '16 at 22:30