On Oct 28, 2015, at 2:02 PM, John R Levine <johnl(_at_)taugh(_dot_)com> wrote:
You could, but that now requires more manual work as people ask why didn't my
message go through, blah blah blah. Having run lists for my church and other
civilians for a long time, I speak from direct experience here.
And this is because the SMTP store-and-forward model requires that error
messages be delivered asynchronously, which is another architectural problem
with SMTP. If error messages could be delivered at the moment of transmission
rather than later, at least most of the time, this wouldn’t be an issue. It’s
entirely possible to do it, but requires a little more sophistication than
Postfix or sendmail have.