I decided to install some very crappy software to get dmarc reporting (my blog) working and adapted a script to suit from a blog, it works you import, report and expire the db.
This is week long plus blog post so i may contradict myself the longer i document stuff.
However with stuff inbound to the database i got no email reports out which i can assume is due to either an error on my part, the policy not to bother them with strict compliance or the software is broken.
A brainwave I had on exploring this was that as a low traffic host (the zoo is not gmail) that email we do get is strictly controlled by rules where gmail i guess might be lax on say spam where as we are not.
So most of the email dealt with needs no dmarc action.
I will run the import , report and expire once a day and see if dmarc reporting via opendmarc is worthwhile.
Later on with reports being sent i observed some issues…
Dmarc can be abused by marketing people, and it depends on who runs the report address they specified take pure360.com.
(host x.GOOGLE.com[74.125.x.x] said:
450-4.2.1 The user you are trying to contact is receiving mail at a rate that 450-4.2.1 prevents additional messages from being delivered. Please resend your 450-4.2.1 message at a later time. If the user is able to receive mail at that 450-4.2.1 time, your message will be delivered. For more information, please 450-4.2.1 visit 450 4.2.1 – gsmtp (in reply to RCPT TO command))
It is amusing to note that they also use gmail.
So dmarc might mismanaged by some who might know better. Does this mean pure360.com dmarc should be ignored? what do you think.
Another retard with dmarc did the below humorous issue – Please note this was collected by dmarc, and sent by dmarc it is not a typo error by a human.
opendmarc-reports: sent report for email3.telegraph.co.uk to email@example.com (2.0.0 Ok: queued as 5F1F4BD6315)
<firstname.lastname@example.org>: host <host>.google.com[74.125.x.x] said:
550-5.1.1 The email account that you tried to reach does not exist. Please try 550-5.1.1 double-checking the recipient’s email address for typos
Plenty of other idiots exist.
(host eu-smtp-inbound-1.mimecast.com[126.96.36.199] said: 451 IP temporarily blacklisted – https://community.mimecast.com/docs/DOC-1369#451 (in reply to RCPT TO command))
(host eu-smtp-inbound-2.mimecast.com[188.8.131.52] said: 451 IP temporarily blacklisted – https://community.mimecast.com/docs/DOC-1369#451 (in reply to RCPT TO command))
These appear to go hours and hours later that is getting the dmarc report back (rac do send spam) and piss off hosts when it reports back – Oh to be a mind reader.
Yet another brainwave i had was that there is no way to block ‘pfishing’ emails via opendkmarc unless there is a strict policy setup. Unless you search headers for dmarc rules but thats down to the mta or spambotter not opendmarc. There is an example below.
Routing loops could be a problem – ala i send mail, they send mail, we mail back etc. Have to see on that one. I guess you could turn off reporting which kind of makes dmarc reporting an odd idea to start with.
In the real world i found out:
If you do not import messages into sql and then close down opendmarc (say for an kernel upgrade) then opendmarc deletes the text file is one bug i noticed – not an end of the world issue but occasional one.
Another bug i noticed in 1.3.0 release (1.3.2 is debian experimental) is that opendmarc-reports will still send email out even if you had a typo in the address or email set in script (the zoo has four domains)
I noticed as our dkim signing did not initiate when it should have (my typo).
The sql data is stored although its not designed for humans to read, the xml reports which it makes and we also get from others as the zoo has dmarc are more human readable.
Microsoft (microshit) are pretty crap at dmarc -there reports leave a lot to be desired due to \n issues.
They also bounce failure – this is pure microshit in action. I perceive this as bit spammy. It took a little time to sanitize here.
Typical crap from microsoft, it was spamcop proof too
Criminals also have odd dmarc setups an good example is quantumaccountingservices . net which is scammy* returned at time of wtiting
Host not found, try again
So i guess your going to get a lot of domains to ignore.
A problem i have is with multiple domain reporting (say mail.zoo mail.zoo1 etc). In the debian 1.3.0 version the first report run for mail.zoo has all the fun the other opendmarc report scripts run but have nothing to report on. That might be a level of complexity most with one domain and one host never get to see or care about and might be down to the shit sql server it uses.
My adsp and atps lines in dns needed some tweaking since reporting uses port 25 and i use the other port for outbound mail which for over a week i failed to comprehend so this might be a postfix / amavis or some other issue i cannot resolve currently.
The zoo will not be sending reports until we figure out adsp (my blog) even though the sql import and expire work
opendmarc-spam looks interesting although a thought experiment needing a look at source code to guess how it works
That’s about it for opendmarc reporting. Tomorrow I will be delving into the science of mind reading** after all it appears to be a required skill with dmarc.
*the hint is in the name. ** i joke