Author: Peter Bowyer Date: To: exim-users Subject: Re: [Exim] Checking against "seen" Message-ID:'s to drop bounces
Russell King said: > On Mon, Jul 12, 2004 at 02:20:12PM +0200, Tor Houghton wrote:
>> So; we thought that one way of cutting down the human processing time of
>> such messages would be to somehow record and check the
>> bounced/undelivered
>> message's ID. Perhaps this is old news, has been thought of before and
>> was
>> rejected as a bad idea.
>
> I think you'll be lucky to find the original message ID in a bounce
> message. You're already lucky if you can parse the intended
> recipients from bounces let alone work out which message it
> corresponds with.
Agreed 100%.
Some people here have discussed an alternative solution which drops a
cryptographically-derived cookie in the return-path of all outgoing mail,
and on the incoming side you reject null-sender mail which arrives to the
'bare' address, and verify the cookie otherwise.
ie
mail sent by peter@???
return-path rewritten to peter-<cookie>@example.com
bounce arrives to peter@??? - reject.
bounce to peter-<cookie>@example.com - if the cookie verifies, accept and
deliver to peter@???, else reject.
Methods of deriving the cookie probably involve the a timestamp and other
things.
