DMARC’s `pct=0` shall not lead to discarding or rejecting a message
In theory the DMARC policies p=none
, p=reject; pct=0
and p=quarantine; pct=0
are equivalent. (In even more theory p=reject; pct=0
is equivalent to p=quarantine; pct=100
, but this reading of the specification serves no purpose).
In practice the p=reject; pct=0
, p=quarantine; pct=0
and p=discard; pct=0
policies shall convince the MLM to do From:-munging, so that senders can verify things work correctly, without enforcing anyhow DMARC. There might be different opinions on this, but the p=quarantine/reject; pct=0
policies, can be the only policies, where From-munging is tested without having any bad impact.
mailman does not evaluate the pct=
parameter. It does have under DMARC mitigation policies, among others, to Discard (delete) the message, or return (reject) it to the sender.
Please extend the DMARC filter rules not to discard messages, when pct=0
is combined with p=reject
, p=quarantine
, p=discard
. It is reasonable under these circumstances, to avoid rejecting the message.