2RFC 7208, "Sender Policy Framework (SPF) for Authorizing Use of Domains in Email, Version 1", April 2014
3Source of RFC: spfbis (app)
9Publication Format(s) : TEXT
10Reported By: David Bürgin
11Date Reported: 2020-06-26
15ptr._spf.example.com. SPF "v=spf1 -ptr +all"
18ptr._spf.example.com. TXT "v=spf1 -ptr:example.com +all"
22The example in appendix A.4, 'Multiple Requirements Example', does not
25In the example, the SPF record at ptr._spf.example.com contains the
28When this directive is evaluated, the <target-name> is equal to
29'ptr._spf.example.com'. An input <ip> such as 192.0.2.10, which has a
30PTR record pointing to 'example.com', will fail to match, as that domain
31is not equal to nor a subdomain of 'ptr._spf.example.com'. In other
32words, given the DNS setup of appendix A, there are no inputs that
33fulfil the requirement for matching this ptr mechanism.
35The example can be fixed by supplying an appropriate <domain-spec>:
36replace '-ptr' with '-ptr:example.com'.