On Mon, 19 May 2008, Alessandro Vesely wrote:
This kind of problem makes me think there's not much benefit to
rejecting messages at SMTP time from trusted clients, whether they are
MUAs or MTAs.
Very much agreed! However, while SMTP AUTH clearly identifies trusted
MUAs, a "trusted MTA" is a somewhat fuzzy concept...
I mean a client MTA on the local network that's using my MTA as an
outgoing relay. The client MTA is often running on a web server or
is a departmental email server.
The one exception that does arise is the occasional deeply broken MUA,
e.g., ones that fail to present any sort of useful error information to
the user. When such MUAs are prevalent (and there are placess where they
are - and again, just because you haven't encountered them doesn't mean
they don't exist) having the option to accept basically anything and
send a DSN later is useful.
IME MUAs keep finding new ways of being deeply broken.
f.anthony.n.finch <dot(_at_)dotat(_dot_)at> http://dotat.at/
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