How to ignore _dmarc for outgoing trafiic?

michabbs

Member
May 5, 2020
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All outgoing mails (sent via port 26) fail on KAM_DMARC_REJECT test:

Code:
pmg-smtp-filter[60054]: 313226187AB1C160A1: SA score=2/5 time=0.658 bayes=0.55 autolearn=no autolearn_force=no hits=ALL_TRUSTED(-1),BAYES_50(0.8),KAM_DMARC_REJECT(3),KAM_DMARC_STATUS(0.01)

This seems because my dmarc policy is set to reject and private IP's are not listed in spf record, and maybe mails from internal hosts do not have dkim signatures yet (pmg adds them). How can I deal with this problem? (How to ignore dmarc on port 26?)

Working solution:
I manually forced my internal dns resolver to hide _dmarc record for my domain. It works, but I don't like it. I am afraid it can affect also regular traffic on port 25, where dmarc validation should be performed normally. (Am I right?)
 
hmm - the issue is that the SpamAssassin config is global for pmg-smtp-filter (since it's the process, that do the scanning both in and outbound) - so disabling a particular rule is only possible globally (meaning for both directions)

One thing you could try is to create a custom spamassassin rule - which assigns a score of -3 if ALL_TRUSTED & KAM_DMARC_REJECT (and thus evening out the score):

https://pmg.proxmox.com/pmg-docs/pmg-admin-guide.html#_custom_spamassassin_configuration

(or just set the custom score for ALL_TRUSTED to -4)

In any case please verify that ALL_TRUSTED indeed only matches mails you get from the internal port

I hope this helps!
 
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