On 30 Oct 1999, Vladimir Litovka wrote:
> Vadim Vygonets <vadik@???> wrote:
>
> > How do you imagine DSN working? When you send message to
> > exim-users, say, who should return DSN where? Possible answers
> > include:
> >
> > 1. Every recipient's MTA to you. Bad, because you should not
> > know who is subscribed to the list.
> [ ... ]
> > 3. exim.org MTA to you. Useless, isn't it?
>
> There is only answer: DSN must be returned, when Exim has passed message
> to non-SMTP transport (appendfile, for example, or pipe - and it's no
> matter, what pipe does with this message, it is matter that message has
> left SMTP "zone"). So, if exim.org uses external mailing list manager,
> which receives messages from pipe, then DSN must be returned by exim.org's
> MTA to me. If exim.org uses aliases for passing message to recipients,
> then DSN must be returned by every recipient's MTA to me.
What if the recipients don't want a delivery notification sent? Who
says only the sender of a mesage gets to decide?
> Don't think about man's mailbox :-) The sender only and nobody else must
> think, what is he doing. And, of course, not author of program.
>
> > 3. exim.org MTA to you. Useless, isn't it?
>
> In this exact case - yes, quite useless. But every time, when I'm using
> DSN, I know, what I want: I want to receive notification, that message was
> successfully _delivered_ to recipient's mailbox.
By the definition of SMTP, and the requirements thereof, if you do not
get a message saying it was not delivered, then it was. Now this wont
hold up in court (but then again, neither would a DSN notice that it
was - just becuase it was delivered doesnt mean it was read - what if
you mailed someone two minutes before their ISP shut off their account
and deleted all their mail?)
Now if you want to do something locally, on a single server, between
employees of a single company, or members of some single organization,
then you can configure your own MTA (exim or otherwise) to function
exactly as you want.. In exim, you could modify the appropriate
transports to send a message back to the sender notifying them of
successfull delivery (be careful not to create a loop tho :)
But on the Internet, its just not feasible, nor universally desirable.
If you've got some sort of vital, life-and-death message to
communicate, or if you want to be able to prove someone got your
message for some legal proceeding, I'd find a more appropriate channel.
If you just want to know something got through, you can always ASK the
recipient to confirm that they got your message (and this goes one
better becuase it's also a good indication that they actually READ it
too).
