Re: Your setting Return-Path to YOU in your cygwin@cygwin postings

[Dave Korn <dave.korn.cygwin@googlemail.com>]

Owen Rees wrote:

> All that would be needed to make this work would be to update all mail
> clients 

  <g>  That's probably the oldest meme on the internet.  "All we need do to
make X work is update every Y in the world".

> I am not convinced that Mail-Followup-To is common practice. Do most
> mailing lists insert it? cygwin apparently does but cygwin-talk does not
> nor do any of the other mailing lists to which I subscribe. Do the most
> widely used clients and webmail services support it?

  It's a client header, so the question is not whether other lists insert it
or not, but how well supported it is by common mail clients.  There's a list
at DJB's page (many years out of date) that mentions qmail, mutt, Gnus, Kmail
and SquirrelMail, and I spent five minutes googling and discovered that since
then it has also become supported by packages such as emacs and Thunderbird.
So it's reasonable to say that it has a fair degree of adoption.

  This is how the internet has always worked: someone proposes an idea, some
other people support it in software, everyone tries it out and if it works
good it gets widely-adopted.  The whole standardisation process is very much
an after-the-fact matter of documenting what the de facto standards are and
providing a gold-standard for interoperability so that any little misaligned
wrinkles between the various implementations can be ironed out.

> It is certainly true that using Return-Path for replies is wrong but
> there are very few circumstances under which it is used at all. The
> return-path line preserves the reverse-path information from the SMTP
> envelope; it is the envelope reverse-path that is used to report errors,
> the return-path line usually does not exist at the point where delivery
> errors are detected.

  The most widespread use is in NDRs, which add "Return-Path: <>" so that you
don't get bounces, loops and explosions of NDRs for NDRs for NDRs and so on.

    cheers,
      DaveK