Having both passes and failures is incredibly useful. The percentage of failures is very useful. Any set of mail streams will always have some failures. Once you know what the baseline rate for a (sub)domain is, simply seeing changes in that rate will help you identify problems. An increase in the failure rate is generally either 1) someone trying to abuse your domain name; or 2) something has gone wrong with DKIM signing or someone associated with the domain organization has started sending mail from somewhere without appropriate SPF or DKIM.
Michael Hammer On Wed, Jul 31, 2019 at 5:24 PM Дилян Палаузов <[email protected]> wrote: > Hello Fredie, > > DMARC limits the amount of servers that can generate emails for a > particular domain. The aggregate reports show to > which extend DMARC does work correctly and when it fails for a domain. > The aggregate reports to not tell you how to fix > your DKIM implementation, so that sender and receiver agree on the DKIM > signature. The per message failure reports tell > you which messages were not signed correctly, so that you can check the > DKIM implementation. > > I thought some hours ago it could be useful to reduce the amount of > reports, by not sending a report when things are > 100% correct, but now I am not so sure. > > The aggregate reports contain information, if something is not working > correctly, but they also prove, if everything is > running correctly. If there is an option to reduce the reports to contain > only information about failures, you don’t > have a prove, that everything is working correctly. Let’s say if you > write a message to site S and don’t get an > aggregate report back, this can mean, that DMARC passed, but it can also > mean, that S does not evaluate DMARC or that > DMARC failed and S does not send aggregate reports. Is the lack of > success-reports a prove of correctness or not? I am > inclined. > > What do you want to do with the information about failures from the DMARC > aggregate reports? > > Regards > Дилян > > On Wed, 2019-07-31 at 19:31 +0200, Freddie Leeman wrote: > > Hi Дилян, > > > > Thanks for your input and feedback. Maybe a single tag, that allows the > domain owner to avoid receiving aggregate reports for messages that align, > would be enough? I personally have little experience with mailing lists > which, I understand, can be a real pain when it comes to SPF/DKIM. So would > a tag that instructs the receiving party to only send an aggregate report > whenever the DMARC policies is applied be a better option? > > > > Kind regards, > > Freddie > > > > Van: Дилян Палаузов [mailto:[email protected]] > > Verzonden: woensdag 31 juli 2019 17:29 > > Aan: [email protected] > > Onderwerp: Re: [dmarc-ietf] Aggregate reporting options tag name 'ao' > > > > Hello Freddie, > > > > if a message has 5 DKIM-Signatures, some of them fail DKIM validation > and some of them do not align, irrespective of validation status, you want > to receive a report for the failed DKIM signatures. The proposed option d > is in the DKIM domain. DMARC without alignment is DKIM or SPF. To get a > report for failed DKIM signature you put in the DKIM-Signature header r=y. > After the mail passes over a mailing list, the signature is invalidated and > you get a useless report. Your intension is to limit the amount of useless > reports, but this particular option goes in the opposite direction. > > > > If you remove the SPF records and ensure that each leaving message is > signed, you do not need the ao=1 option, as each report on failure will be > about DKIM. > > > > With ao=s whenever a mail is sent to an alias and redirected to another > server, you will get a useless report. I am not exactly sure, but I think > SPF contained some reporting mechanisms, so this option might duplicate > them. > > > > Perhaps you want to propose a mechanism, that hides the successful > deliveries (useless report) and only reports problematic cases? > > > > Regards > > Дилян > > > > > > On July 31, 2019 5:58:18 PM GMT+03:00, Freddie Leeman <freddie= > [email protected]> wrote: > > > Would it be useful to add an ‘ao’ tag name for aggregate reporting > options? Something like: > > > > > > ao: Aggregate reporting options (plain-text; OPTIONAL; default > is "0"). > > > Provides requested options for generation of aggregate reports. This > tag's content MUST be ignored if a "rua" tag is not specified. The value of > this tag is a colon-separated list of characters that indicate aggregate > reporting options as follows: > > > > > > 0: Generate a DMARC aggregate report for every message, regardless of > its alignment. > > > 1: Generate a DMARC aggregate report if any underlying authentication > mechanism produced something other than an aligned "pass" result. > > > d: Generate a DMARC aggregate report if the message had a signature > that failed evaluation, regardless of its alignment. > > > s: Generate a DMARC aggregate report if the message failed SPF > evaluation, regardless of its alignment. > > > > > > This would allow domain owners to save on tons of reports to be > handled and processing that are useless in most scenarios. For instance, > when I’ve deployed my SPF/DKIM/DMARC policy and I’m pleased with my > policie’s results, I would still want to use the reporting to detect and > fix changes in my email environment. If a million mails a day are nicely > processed with DKIM and SPF aligned, I do not need those entries in my > aggregate reports. I’m only interested in the reports where either DKIM or > SPF fails. In most scenario’s this will cut data transfer and report > processing with more than 99 percent. Whenever there is a bump in the > number of reports received, I can detect that something is wrong and I > might need to add a host to my SPF policy or need to fix my DKIM signing. > > > > > > I was amazed that these options weren’t in the current RFC, as these > do exist for failure reports. Am I missing something? Is there a reason why > this would be a bad idea? > > > > > > Kind regards, > > > Freddie > > > > _______________________________________________ > > dmarc mailing list > > [email protected] > > https://www.ietf.org/mailman/listinfo/dmarc > > _______________________________________________ > dmarc mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/dmarc >
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