[Mailman-Users] Resolved Mostly): New to Mailman 2.1.23 - group e-mails arriving as spam...

[Stephen J. Turnbull]

rabin505 at sasktel.net writes:

 > I would still be interested in seeing and documentation on a known
 > good list configuration to ensure

That doesn't exist.  Spam fighters generally believe their users would
rather lose mail than receive spam, and act aggressively on that
belief.  Some sites have worse problems, like leaking over 100 million
user address books, and they act even more aggressively.

Also, in general it's not the list configuration that triggers spam
filters.  It's general site reputation and message content.  I don't
know why your webmail likes Wrapped messages so much.

What you can do to protect your site's reputation:

1.  Check that your IP address is not in any DNS block lists.  If it
    is, sometimes you can request a new allocation.
2.  Spam filter mail incoming to Mailman aggressively.
3.  If you have human mail users on the host, or lots of services
    running, you might want to filter on outgoing mail as well.
4.  Use DKIM (and optionally SPF) to authenticate your outgoing
    messages.
5.  (Optionally) participate in DMARC (not terribly useful for a
    Mailman site usually).
6.  Use the ARC protocol to placate some sites (ARC usage is not
    universal yet, and AFAIK there are as yet no best practices for
    when to trust ARC-based claims of verified authentication).  ARC,
    like most of these protocols, is best implemented in the MTA.
    However, Mailman 3 does have an option to implement ARC in
    Mailman.  (This will probably not ever be backported to Mailman 2;
    for Mailman 2 ARC can only be implemented by your MTA.)

I'm not sure what to say about content.  My own site has obnoxiously
high rates for both false positives and false negatives, and I have
not been able to detect a pattern for these errors. :-(

Steve