Spf2.0 - Sender ID

We did get a few questions about spf2.0. spf2.0 refers to Sender ID, which is not what SPF is. I know it sounds confusing, but it is two completely different things.

The main difference between the two is what is being validated.

  • SPF validates the envelope from (mail from, return-path)
  • Sender ID isvalidates one of the message’s address header fields defined by RFC 2822

Sender ID (Microsoft Protocol) can do what SPF does because Sender ID was derived from SPF, but it uses different tags to define what to validate in the message headers, and is not used by DMARC.

Also, Sender ID has become an obsolete standard.

The most interesting is that there are some large ISP out which still gibe you a better anti-spam verdict should you publish beside your SPF record also a Sender ID txt record.

While there is no real value for DMARC it can still improve the deliverability of your emails.

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There are different opinions on that.