On 01/01/2018 01:30 PM, Alan Hodgson wrote:
On Mon, 2018-01-01 at 10:29 -0500, Bill Cole wrote:
On 1 Jan 2018, at 9:59 (-0500), David Jones wrote:
I think some mail systems will keep the same message-ID per email
thread so your system must reject some replies.
I have not seen such behavior in the past 20 years...
Intentionally re-using another site's MIDs is so wrong that I'd happily
make it break hard.
HOWEVER, the idea of enforcing any standard on MIDs beyond gross format
(e.g.: <[[:ascii:]]{3,996}>) on a system where the admin isn't the sole
user is ludicrous.
I've had good success junking anything with one of my domains in the
message-id, where I know the mail isn't actually from someone in that
domain. That's a pretty solid spam signature.
I too have seen spam with my own domain in the Message-ID but I combined
it with a meta rule of !ALL_TRUSTED to be safe. You are correct. This
is a good indicator of spam but each person is going to have to create
this local rule unless someone wants to write a plugin that can detect
this dynamically.
Lack of any message-id is also significant, but sadly there are still
some real senders sending mail with no message-id.
--
David Jones
