Re: [Evolution] Return receipts

[Nigel Metheringham <Nigel Metheringham vdata co uk>]

The discussion on this thread has already shown one form of
return-receipt I have never seen before, and passingly gone past the 2
other versions I do know about....

To take these in turn:-

  1. Return-Receipt-To: <addr>
     Sends a receipt to the address specified.  Great for using
     on mail to large mailing lists with a 3rd (disliked) party
     address in the header.   Implemented in old sendmail's
     and maybe even in old RFCs.
     Implementation of return function is in MTA on final delivery
     Very strongly deprecated nowadays - and finding MTAs that
     support it is now pretty hard.

  2. DSNs
     There are RFCs for these (several I think).
     Complex, return function can be either MTA or MUA,
     also used in some cases for bounces.
     Generally the best but most complex to implement.
     Need options to allow/disallow/ask about replying.

  3. X-Return-Receipt-Requested: true
     Microsoft's answer.  Has same privacy implications as
     others, but at least avoids some of the 3rd party problem
     of the original Return-Receipt-To:

Dan makes some really good points about implementation issues.

        Nigel.