[colug-432] Why my list mail is often tossed or winds up in spam folders...

Rob Funk rfunk at funknet.net
Tue Jan 12 09:32:55 EST 2016

Rob Stampfli wrote:
> On Mon, Jan 11, 2016 at 08:39:49AM -0500, Scott Merrill wrote:
> > GMail thinks your message is spam.
> The problem is that DMARC doesn't interact well with mail exploders.
> Indeed, it breaks the traditional way of handling list mail, which
> retains the sender's email address in the resent list email, but
> alters the message (changes the Subject line, adds a footer, etc.)
> in a way that it no longer passes the DMARC check.  This is a well-
> known problem which has had to be addressed by all mail exploders
> including the big boys like YahooGroups.  It is one of the reasons
> I stopped managing my own email lists.
> Colug still adheres to the old standard of leaving the From: line
> intact, as described above.

>  I've been running DMARC
> for over a year now, and colug is about the only place left where
> there is a significant problem with my legitimate emails.  I'm not
> extremely active here, so I've elected to just live with it.

I noticed some of this sort of thing when I fixed my DKIM setup last
week. (Turns out Ubuntu dropped dkim-filter in favor of opendkim a
while back, but didn't tell the packaging system about it.) COLUG's
mangling of the Subject line and body make DKIM checks fail, though I
don't have a hard reject set on my domain, so it's not a huge problem.
I think the generally recommended solution is for list remailers to do
cryptographic message signing themselves.

(I'm still a little fuzzy on DMARC, but my understanding is that it
builds on DKIM.)

> Whether you consider DMARC as a useful tool or the work of the devil,
> it appears to be here to stay.  And if you're still interested,
> google "DMARC breaks lists" and you'll get an eyeful.

The trouble is that the necessities of spam filtering have broken our
federated email system, with trust of smaller servers breaking down.
Everybody trusts Gmail, but otherwise you may be filtered out just
because you're unknkown. For a while I was having a lot of trouble
getting email to friends with Yahoo email accounts, and had to use
Gmail to email them.

These cryptographic email technologies can be a pain, especially when
things break, but when they don't break they do seem to help make
email more likely to be accepted by skeptical servers.

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