Thank you for response, Matt. Actually I am well aware that adding MX to SPF makes no sense, at least when you use cloud mailbox providers, like G Suite, O365 etc, which have specially tailored 'include' mechanism for their sending IPs/subnets
My question is different. I am aware that despite MX is redundant for G Suite/O365/etc., it is still heavily used in SPF records of many organizations and is almost always is the second in the row, after A mechanism (thanks to many online SPF record generators) So I want to understand whether having MX placed in the beginning of SPF record can cause a quicker reach of '10 DNS lookup limitation' for G Suite senders, due to the reason that G Suite has 5 MX records (and I assume that number of DNS queries, executed to resolve MXes to IPs, is 6 and not 1) Regards, *Alexander* On Wed, May 19, 2021 at 5:15 PM Matthäus Wander via dmarc-discuss < dmarc-discuss@dmarc.org> wrote: > Alexander NAZARIAN via dmarc-discuss wrote on 2021-05-18 20:40: > > Different online SPF checkers show different results. > > > > [...] > > > > So, looks that mailbox providers count MX mechanism as 1 lookup (no > > matter how many hostnames MX record resolves to) and dmarcanalyzer.com > > <http://dmarcanalyzer.com> tool lookup check have nothing with reality, > > > > Could you help with understanding how many DNS queries are being run for > > the MX mechanism ? > > You've shown two different interpretations of the SPF specification. To > me, which of these is the correct interpretation is of less importance > than the fact that both interpretations exist. If high deliverability is > desired, it's thus wise to comply with the more strict interpretation. > > In the concrete example, the "mx" mechanism is redundant to > "include:_spf.google.com" and can be omitted. > > Regards, > Matt > _______________________________________________ > dmarc-discuss mailing list > dmarc-discuss@dmarc.org > http://www.dmarc.org/mailman/listinfo/dmarc-discuss > > NOTE: Participating in this list means you agree to the DMARC Note Well > terms (http://www.dmarc.org/note_well.html) >
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