Probably, this question is from misunderstanding on how DNS round-robin works. a:dispatch-us.ppe-hosted.com causes SPF to query A record for dispatch-us.ppe-hosted.com. Response for this query contains _all_ A records (not a random one, as you probably think). It means every IP from the list below is authorized. DNS round robin is performed by server randomely choosing the order or A records in the list and/or client randomely choosing the record from list.
24.01.2019 18:47, Eric Tykwinski пишет: > > I’ve got a customer receiving emails from ProofPoint and failing SPF. > > Looks like they followed this page on ProofPoint’s website: > > https://support.proofpointessentials.com/index.php?/Knowledgebase/Article/View/346/0/why-is-spf-check-failing-with-office-365 > > > > Basically, add “a:dispatch-us.ppe-hosted.com” to your current SPF record. > > $ dig +short dispatch-us.ppe-hosted.com > > 148.163.129.52 > > 148.163.129.53 > > 67.231.154.189 > > 67.231.154.184 > > 148.163.129.62 > > 67.231.154.188 > > 67.231.154.187 > > 67.231.154.164 > > 148.163.129.49 > > 67.231.154.183 > > 67.231.154.186 > > 148.163.129.58 > > 148.163.129.56 > > 67.231.154.165 > > 148.163.129.63 > > 148.163.129.48 > > > > Is this a legit method? Looks like it’s a typical round-robin so will > fail more often then work.. > > > > Sincerely, > > > > Eric Tykwinski > > TrueNet, Inc. > > P: 610-429-8300 > > > > > _______________________________________________ > mailop mailing list > [email protected] > https://chilli.nosignal.org/cgi-bin/mailman/listinfo/mailop -- Vladimir Dubrovin @Mail.Ru
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