I was reminded that the Obtuse SMTP daemon was doing this in 1997.
Should be good prior art to bust this patent if anyone cares.
To follow myself up, it took about five minutes to find a copy of the
obtuse daemon 2.0, released in 1997 and not changed since then, and
verify that among its features is a file of accept/deny info that
includes To and From addresses, either literal or patterns, used
to control what the SMTP daemon does.
Considering how popular the Obtuse daemon was in the late 1990s, it's
hard to see how even a cursory search would have missed it. It was
famous for its goofy status messages, e.g.:
220 SMTP ready, Who are you gonna pretend to be today?
500 Bloody Amateur! Proper forging of mail requires recognizable SMTP commands!
R's,
John
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