bonjour,
depuis peu de temps, sur mxtoolbox.com (find problem), j'ai ça pour tous mes serveurs exchange :

More Information About Dmarc Record
Hostname returned a missing or invalid DMARC record
Domain-based Message Authentication, Reporting, and Conformance (DMARC) is a mechanism for improving mail handling by mail-receiving organizations. The ultimate purpose of DMARC, according to RFC-7489 is to provide a “mechanism by which email operators leverage
existing authentication and policy advertisement technologies to enable both message-stream feedback and enforcement of policies against unauthenticated email. Email originating organizations utilize DMARC in order to express domain-level distribution policies/preferences
for message validation, disposition, and reporting.
The DMARC Check will return either “Record Found” or “Missing/Invalid DMARC Record”. If the tests returns “Missing/Invalid DMARC Record” then we were not able to find a DMARC TXT record or there were syntax issues with your DMARC Record.
How DMARC Works:
DMARC policies are retrieved by the mail-receiving organization during a SMTP session, via DNS. When mail receivers query DNS, they look for a DMARC TXT record at the DNS domain that matches the one found in the
RFC5322. From domain in the email message. If a policy is found, that policy is combined with the author’s domain and the SPF and DKIM results to deliver a DMARC policy result. This policy result
will be either “pass” or “fail” and may cause a report to be generated. If a policy is not found, the DMARC module determines the organizational domain and
repeats the attempt to retrieve a policy from the DNS.
Having a DMARC message handling policy is currently not required, but recommended as it improves mail-handling between both the sending and receiving organizations.
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les enregistrements SPF et reverse DNS sont bien OK (sinon j'aurais des erreurs également)
que faut-il faire chez l'hebergeur ? le F.A.I. ? ou le serveur exchange pour résoudre ce souci ?
Cordialement