On 24Nov2020 12:09, Ian Zimmerman <i...@very.loosely.org> wrote:
>On 2020-11-24 17:22, Chris Green wrote:
>> > > I'm on a couple of mailing lists that have recently moved from
>> > > Yahoo Groups to groups.io. For DMARC (so they claim) groups.io
>> > > change the senders E-mail address as follows:-
>> > >
>> > > Sender Name <sender.n...@btinternet.com>
>> > >
>> > > becomes:-
>> > >
>> > > "Sender Name via groups.io" <sender.name=btinternet....@groups.io>
>
>> It only happens to users from some domains. [...]
>
>It is because those senders subscribed with an address covered by a
>strict DMARC policy. If their address is not munged by the list, their
>messages will be bounced back to the list by almost everyone if they
>fail a DKIM check (and that's almost always). [...]
>
>There's no good automatic solution to build into a MUA for this, as far
>as I know. The best you can do is write a macro to extract the true
>sender, and feel lucky for using a MUA that allows that :-)
I have an unmangle step in my mail filer. I'll list the rules at the
bottom of this message.
Basicly, for particular sources I hack the From: line around. For yahoo
lists the original address was embedded in the From: header itself, for
mercur...@mercurial-scm.org the Reply-To: header holds the original
author, for us...@lists.fedoraproject.org the X-Old-From: header holds
it, for core-mentors...@python.org it is in the X-MailFrom: and so
forth. So there's a suite of special purpose rules below.
The rule syntax below is "target condition...", so each of the:
from:s/this/that/
lines is a "target" and the other lines constraint which messages it is
applied to.
I imagine you could do something with procmail like this. See the
"formail" command. If formail won't do it, a sed script probably will.
Note that this of course mangles the headers, a price I've been willing
to pay for sanity.
Cheers,
Cameron Simpson <c...@cskk.id.au>
# undo Yahoo Groups DKIM/DMARC mangling
# if we ever check the validity of this stuff it will need to be before this
step
from:s/"(?P<fullname>.*\S)\s+(?P<coreaddr>\S+@\S+)\s+\[(?P<listname>[^
]*)\]".*<(?P=listname)(-noreply)?@yahoogroups.com>/"$fullname" <$coreaddr>/
sender:/@yahoogroups.com
from:/@yahoogroups.com>
from:s/"(?P<fullname>.*\S)\s+(?P<coreaddr>\S+@\S+)\s+\[(?P<listname>[^
]*)\]".*<(?P=listname)@yahoogroups.com>/"$fullname" <$coreaddr>/
sender:/@yahoogroups.com
from:/@yahoogroups.com>
from:s/"(?P<coreaddr>\S+@\S+)\s+\[(?P<listname>[^
]*)\]".*<(?P=listname)@yahoogroups.com>/<$coreaddr>/
sender:/@yahoogroups.com
from:/@yahoogroups.com>
from:s/.*/$reply_to/
sender:mercurial-boun...@mercurial-scm.org
from:/ via Mercurial <mercur...@mercurial-scm.org>
# undo Linux Australia header mangling
from:s/.*/$reply_to/
sender:linux-aus-boun...@lists.linux.org.au
from:linux-...@lists.linux.org.au
from:s/.*/$x_mailfrom/ from:core-mentors...@python.org
x-mailfrom:/@
list-id:/core-mentorship.python.org/
from:s/.*/$reply_to/
from:(python-l...@python.org|python-id...@python.org|python-...@python.org|tu...@python.org)
# fedoraproject.org x-mailfrom
from:s/ via users <us...@lists.fedoraproject.org>/ <$x_mailfrom>/
from:(us...@lists.fedoraproject.org)
# googlegroups x-original-from
from:s/ via users <us...@lists.fedoraproject.org>/ <$x_original_from>/
from:vim_...@googlegroups.com
