[Mimedefang] Greylisting++

[John Rudd]

Kees Theunissen wrote:
> On Mon, 9 Jul 2007, John Rudd wrote:
> 
>> I've often wondered about including the message-id in the tuple, as
>> well as trying to track the same message-id coming from different
>> senders, and whether or not that's a usable spam-sign.
> 
> In case of mailing list trafic you should be prepared to receive the
> same message from two different envelope senders if someone replies
> to your message with "To: list" and "Cc: you". In both cases the
> "From:" message header will be the same, but you need to implement
> greylisting after the SMTP DATA command to be able te inspect the
> "From:" message header.
> 

Yes, you have to wait that long to get the message-id, too.

It also depends somewhat on what the mailing list does with the from 
address and/or message-id.

I think the biggest problem is damaged mailing list services like Yahoo, 
where they send a unique message to every recipient, even if they're at 
the same site, and each one gets a unique envelope-from.