On 20211112, at 20:33, Dirk Hohndel via subsurface 
<[email protected]> wrote:
> 
> And I finally broke down and implemented DKIM on the server (as Linus and I 
> speculated that that might help to not be "disappeared" by gmail).

Yeah, these are sucky tactics, and in many cases, unless you have personal 
contacts at the big orgs you are going to be stuck not delivering.


DKIM is not going to be enough, and as you are already doing you are rewriting 
the From header (which is annoying as reply-to gets munged etc.)


In order to be 'accepted' by the large orgs, a combo of at least:
 - don't be in a /24 or /48 with spammers, IP neighborhood matters
 - IP/domain reputation matters (high volume can thus spam 1%, low volume means 
with 1 'spam' mail you might be out...)
 - have forward + reverse DNS matching (forward verified reverse or whatever it 
is called)
 - SPF (-all)
 - DKIM
 - DMARC (strict)
 - ARC (Authenticated Receiver Chain aka DMARC for forwarders)
 - List-Unsubscribe + Precendence: List
 - Signup to google postmaster + outlook SNDS if you have your own IPs, so that 
it indicates that you 'care'...

And that is the bare minimum.... most of those boxes are being ticked already.

Note that proper big spammers have that all setup nicely, places like Gmail 
where most spam come from of course have such high volumes that any 'small 
spamrun' just comes through.

If you need any help with the above don't hesitate to ask.


Oh, please note that because of the header:

From: Dirk Hohndel via subsurface <[email protected]>

MUAs that auto-add people you reply to in the address book.... auto-complete 
for your name, becomes the mailinglist.

Add to that that Safari and Outlook both are stupid and then auto-fills the 
name of a person based on that entry... voila, first mail somebody replies to, 
all subsequent mails come from that person for the list...

The way around that, as I implemented for Trident, is the 
<jeroen%[email protected]> format, as then there is a unique address that 
can be reversed to the original address; but that also implies that for Reply 
to the From address needs to arrive at the original recipient and thus has to 
be rewritten.



Note that the following:

Authentication-Results: massar.ch;
        dkim=pass (2048-bit key; unprotected) header.d=subsurface-divelog.org 
[email protected] header.a=rsa-sha256 header.s=2021 
header.b=T84KKRk5;
        dkim=fail reason="signature verification failed" (2048-bit key; 
unprotected) header.d=hohndel.org [email protected] header.a=rsa-sha256 
header.s=2021 header.b=oEnVr5CJ;
        dkim-atps=neutral

Shows that the hohndel.org DKIM header was still present. ARC covers that part, 
to make Google a bit happier in your host declaring that you verified, but then 
broke that sig.


The big orgs are making it on-purpose hard to do your own, as they know that 
they then get more of the mail on their platforms, and every bit of data helps 
:(   [not that something like 80% of mail ends up there anyway, thus they 
effectively see it all unfortunately, and with domain hosting and forwarding 
one never knows where your mail ends up; PGP oh meh... to protect sensitive 
stuff...]



As for Mailman: one thing that really helps is changing the standard URLs for 
the signup page, makes it harder for bots to get there, and script kiddies 
would then have to manually change the scripts they have, and that, is hard for 
them.



Greets,
 Jeroen
  ... still running my own mail servers, and hope that it remains possible...

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