[ExI] Fwd: Delivery Status Notification (Failure)

[spike at rainier66.com]

John, you are on my short list of people who can do no wrong.  You are on a
still shorter list of those who can do actual literal wrong but still stay
on the first list in spite of the obvious logical contradiction.

Thanks for all you do.

spike



-----Original Message-----
From: extropy-chat <extropy-chat-bounces at lists.extropy.org> On Behalf Of
John Klos via extropy-chat
Sent: Monday, 15 January, 2024 8:26 AM
To: efc at swisscows.email
Cc: John Klos <john at ziaspace.com>; efc--- via extropy-chat
<extropy-chat at lists.extropy.org>
Subject: Re: [ExI] Fwd: Delivery Status Notification (Failure)

> I get the same error and I don't have gmail. That leads me to believe 
> that the error is server-side and not client-side.

When we have limited information, we sometimes come to conclusions that make
sense but aren't necessarily correct. Luckily, we have logs ;)

For your mail server (mail-gate.swisscows.email), it seems that the reverse
DNS PTR for that server should point to a primary name, but it does not (RFC
1034, section 3.6.2, for anyone who is curious). But that's not directly why
email was rejected, though - it was rejected because the extra lookup due to
that CNAME took too long, which is why it happens only sometimes.

You can write to your email provider and let them know, and perhaps they'll
fix it (feel free to include that paragraph and/or cc me - I'm happy to
provide logs and more informtion). Isn't it better to fix the problem than
the symptom? :)

For MB, I only see three failed attempts back in August and October. If this
is happening more often than that, then I'd need more specific information
to find any rejections in the mail logs (the logs are typically thousands of
lines a day). Feel free to email me directly, if this is the case.

I do see that describing this as "Intrusion" can be a bit misleading. I put
that in there for all of the connecting machines that attempt to log in to
try to send email through the server, and it matches clients that don't
identify themselves AND servers that have names that don't resolve (even if
it's just temporary).

To make this less of a pain, I'm making the error transient so your email
server(s) will retry before they fail. You might get a warning, but you
won't have to do anything yourself.

I'm also changing the message to "Given name from (client_addr) does not
make sense."

I'm sending this to the whole list to encourage anyone who has issues to
contact me directly. Whatever happens, we'll figure it out!

Thanks,
John
_______________________________________________
extropy-chat mailing list
extropy-chat at lists.extropy.org
http://lists.extropy.org/mailman/listinfo.cgi/extropy-chat