Re: Not usable email content encoding

[Christopher Faylor <cgf-use-the-mailinglist-please@sourceware.org>]

On Wed, Mar 18, 2020 at 04:42:13PM +0000, Michael Matz wrote:
>On Wed, 18 Mar 2020, Frank Ch. Eigler via Gcc wrote:
>> Yes, for emails from domains with declared interest in email
>> cleanliness, via DMARC records in DNS.  We have observed mail
>> -blocked- at third parties, even just days ago, when we failed to
>> sufficiently authenticate outgoing reflected emails.
>
>Was this blocking also a problem before mailman (i.e. two weeks ago)?  
>Why did nobody scream for not having received mail?  Or why is it blocked 
>now, but wasn't before?  Can it be made so again, like it was with ezmlm?

We *were* seeing an increased number of bounces because qmail wasn't
doing the right thing.  People were complaining to postmaster that they
hadn't received email.  I was dreading having to figure out what DMARC
issues they were having with ezmlm/qmail.  So, it's nice for us admin
volunteers to have a standard system to use that doesn't require
searching for patches or workarounds non-standard systems like ezmlm/qmail.

>(And DMARCs requirement of having to rewrite From: headers should make it 
>clear to everyone that it's stupid).

I hate the rewriting quite a bit.  But, if major players like gmail have
adopted DMARC then there really isn't much we can do except to play
along.  It is galling, but the alternative is telling people not to use
gmail or yahoo.  We obviously can't do that.

I'm not sure that everyone understands that on the old server we were
using an ancient, hacked email system of qmail and ezmlm.  I'd added
unofficial (if official even means anything) patches and work arounds
to allow us to continue to communicate with, e.g., yahoo and qmail but
they never worked 100% right and, as mentioned, we were starting to see
bounces and complaints.  Even the old system munged From addresses, too.

We decided for server2 to standardize on postfix + mailman because both
were available on RHEL.  Using postfix + mailman means that if anything
happens to fche or cgf, it should be possible for some hypothetical
volunteer to figure out how email works on sourceware.

There is at least one site that offers qmail and ezmlm packages but
the support seeemed somewhat iffy.  And, if we had used those instead,
and they had updated their support for DMARC/DKIM/SPF then we'd be
in the same boat anyway.

mailman is supposed to only munge From addresses from domains that
enforce DMARC but we're finding that some domains don't properly
advertise themselves and email is not going through to them.  So, it is
looking like we may have to turn it on universally.

The bottom line is that mailman tries harder to make sure that mail gets
through than the kludge I added to qmail ever did so, in theory, more
mail should get through once we finish tweaking.

FWIW, I rewrote my local email delivery agent so that it it puts most
of the From addresses back the way they were before.  It catches most
of the munging so that I don't even notice it anymore.

cgf