Bernard Hemmings writes:
> My hosting company uses version 2 of mailman
Does it use our release of Mailman, or cPanel's "Mailman 2.2" fork?
If the latter, the code was heavily modified by cPanel, and we have no
access to their source code. We can't help you with that.
The following comments may or may not apply to cPanel Mailman 2.2.
I'm assuming you're using GNU Mailman 2.1, hopefully newer than 2.1.35
(current is 2.1.39, released in December 2021).
> and over the past 2 months I am getting so many of these bounce
> error messages.
>
> Action: Subscription bounce score incremented.
> Reason: Excessive or fatal bounces.
>
> I am getting these regardless of whether the recipient receives
> list traffic or not.
Do you have DMARC mitigations enabled? If not, whether your list
traffic is rejected will depend on the author (From header field) for
most recipient systems (especially the professionally-run ones).
Also, there is a Gmail-specific mitigation that only quite recent
Mailman 2 has.
> Eventually I had to unsubscribe all list members to demonstrate to
> my hosting company my accounts were not sending spam. After a week
> during which time I tested every member's address using a gmail
> account
This is not an accurate test of issues with Mailman, though. This is
a test of "nobody dares ban gmail, but I never heard of your host so
you lose", and maybe "your host is sending a lot of mail and I don't
trust you enough to keep accepting it". To test Mailman issues, you'd
need to install another list manager, send list messages through that,
and see if it has the same issue.
What you can do short of that: Make sure that your host
1. checks for and rejects spam and other malicious incoming traffic
2. provides SPF records via the DNS
3. provides DKIM keys via the DNS
4. correctly DKIM signs outgoing email (this can be a fight, as some
DKIM systems don't like to sign email From another system, but
this is helpful sometimes)
5. (optional) check local-origin email for spam on the outgoing side
It may also be useful if your hosting service participates in the ARC
protocol. This allows your mail server to check for spam, and then
cryptographically sign a header that testifies that your server
authenticated the message and it passed.
This mitigates the problem that the original sender's DKIM signature
is now invalidated by changes that Mailman makes to the Subject header
field and the body of the message. All the hyperscale providers like
Gmail, Yahoo, and Microsoft pay some attention to ARC, but nothing is
a guarantee of delivery anymore. :-(
> I removed these 70 addresses many being hotmail addresses.
Hotmail is a Microsoft property, and Microsoft manages email for many
other domains. It is famous for randomly deciding it doesn't like a
certain email source. This happens to me personally regularly. But
even Microsoft doesn't dare mess with Gmail.
Unfortunately, you can't tell your users to switch email providers.
That said, you need to be aware that unless your mail server (not
Mailman) is doing something Wrong, you're at the mercy of recipient
systems which put much higher priority on rejecting spam than on
accepting legitimate email.
> I have used mailman for many years but if all email from my hosted
> domain is suspended again I'll have to find another email list
> system.
Of course it's possible it's Mailman, but Mailman's outgoing mail is
as vanilla and standard-conforming as any list manager's. I don't
think changing to a different mailing list manager will help you.
Your hosting service (or alternative hosting services) more familiar
with you and your mail flows may give you different advice, though.
That said, this looks to me like recipients don't like something about
your host. Assuming that the configuration of SPF, DKIM, and
(optionally) ARC are proper, and you have DMARC mitigations enabled in
Mailman, what might help is changing outgoing mail to go through a
relay like Sendgrid. Unfortunately I'm pretty sure your volume is
going to kick you out of the free tier for Sendgrid at least (and that
only lasts for 6 months, anyway). There are also problems with the
bulk mailers that you may not be allowed to control certain headers
that Mailman needs to set to work properly (YMMV, depending on what
Mailman services such as archives your users depend on).
That said, Mailman 2 is 3-4 years out of support. Mark continues to
provide patches on a time-available basis for easy fixes, but there is
never going to be another Mailman 2 release from the GNU Mailman
Project. It also depends on Python 2 which is out of support since
April 2020, and as far as I know there are no patches available for
that at all.
Our recommendation is that you (or your hosting service) migrate to
Mailman 3 as soon as you reasonably can. So I encourage you to think
carefully about what you want to do. If you decide to migrate to a
different list manager, there's no point in migrating to Mailman 3
first.
Steve
--
GNU Mailman consultant (installation, migration, customization)
Sirius Open Source https://www.siriusopensource.com/
Software systems consulting in Europe, North America, and Japan------------------------------------------------------
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