[ovs-dev] explanation and workaround (was: Re: OVS mailing lists *sometimes* replace the From: address by the list address)

Ben Pfaff blp at ovn.org
Mon Mar 25 20:13:01 UTC 2019


I obtained an explanation from LF about this issue.  It is not due to an
mailing list configuration change.  It results from DMARC, which is a
setting for email sender domains that causes receivers to reject email
that is allegedly from the domain if it cannot be verified that it
really came from it.  Since mail to mailing lists break these rules,
Mailman and other mailing list software rewrites From headers with DMARC
senders so that the messages do not appear to originate from them.
Otherwise, the receiver would probably discard the email, since it
breaks the DMARC rules.

The most likely reason that we are seeing this often now is that some
new domains have turned on DMARC.

We can't do anything about this directly, because we don't control DMARC
on senders' domains and we don't control email processing on receivers.

I wrote the following script to un-rewrite the From: header before
passing it to git-am.  It isn't perfect but it worked on the few
examples I tried.

#! /bin/sh
tmp=$(mktemp)
cat >$tmp
if grep '^From:.*via dev.*' "$tmp" >/dev/null 2>&1; then
   sed '/^From:.*via dev.*/d
        s/^[Rr]eply-[tT]o:/From:/' $tmp
else
   cat "$tmp"
fi | git am "$@"
rm "$tmp"


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