Can you show instances in which they say yes to messages they cannot deliver?
VS> I was skeptical of the report that Yahoo defers no-such-user responses
VS> until the DATA command, and so I made the obvious `telnet ... 25` test.
VS> I tried a perfectly valid message to an address that was very unlikely
VS> to exist. The Rcpt_To command was answered with at 250 response. It
VS> was not until the end of the DATA command that I got a 5yz.
Folks, the email operations world has increasingly moved away from
real-time processing of SMTP data.
Processing causes delays and SMTP client daemons are impatient. The
very, very wide range of network delays has compunded the effect of
these processing delays, constantly causing problematic timeouts.
So the tendency, these days, is to just say 'yes' in the protocol, take
the addresses and content, store them in a queue, and do any real work
after the connection closes.
d/
--
Dave Crocker <mailto:dcrocker(_at_)brandenburg(_dot_)com>
Brandenburg InternetWorking <http://www.brandenburg.com>
Sunnyvale, CA USA <tel:+1.408.246.8253>, <fax:+1.866.358.5301>
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