Say, I don't have these records for a domain at all and the email delivery is OK.

Will those records improve something regarding the delivery or are they just a remedy for domain spoofing and are not obligatory?


All systems are created differently; nobody knows how Microsoft, Google, Yahoo works internally.

Most spam detection systems are score based, and once a score reaches a certain threshold an email is considered spam.

Let's just for reference take the open source standard, Spamassassin. SA has a lot of rule based checks in place, and if a score is >= 5 an email is considered as spam. The score is being calculated by the addition of all scores generated by the rules.

Having a correct DKIM/SPF/DMARC reduces the score to a certain degree, because it generates negative values.

Most likely the proprietary solutions of the big mail services are using a similar approach, but also please note that this is just one check amongst many others.

So having those records in place might help getting delivered emails to tougher configured services like Gmail more easily. Then again if delivery is already working for you it means that your email goes through so it won't have any impact on delivery.

  • Spam is usually scored on a lot of elements, such as Helo name match with pointer record, IP reputation, links in email corresponding to email domain, etc. I'd say email authentication always improves chances of Inbox delivery.
    – Reinto
    Dec 23 '19 at 19:11
  • When the above mentioned technics were introduced, spammers were the first to adopt them for their own spam domains before they became wider spread and adopted. So using this technics per se is no guarantee that all MX hosts are going to improve the chance of delivery when such a triple is there and correct. Dec 30 '19 at 18:30
  • Well, yes. But spammers implemented it for domains they own. Authentication generally proofs that you own or, at least manage a domain.If you send on behalf of a domain with a neutral / good reputation, authenticating will improve your deliverability. Of course if you successfully authenticate a (SPAM) domain with terrible reputation, authenticating it might harm deliverability.
    – Reinto
    Jan 5 '20 at 19:59

Short answer: yes.

Long answer: If the mail server you've set up doesn't support these mechanisms, there's a good chance that other mail servers will reject mail coming from it, because they have no way to know whether the mail is really from your mail server, or if it's just a spammer pretending to be you.

Of course, it all depends on how the receiving mail server is configured. If it's very lenient with identity checking, it might just gobble up/relay any mail you send to it. But that would be a badly configured server. (And you should also configure yours not to just relay any mail, otherwise spammers will abuse your server and you'll end up being blacklisted.)

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