John C Klensin wrote:
I considered this and even a special extended status code but
stopped because the key part of the SMTP extension is parsing
the response text, which as far I am aware of, there are no
known SMTP practice to do so (outside of proprietary or
localized) due to the idea we can't rely on it to be
I'm not sure what you mean. Certainly the responses to VRFY and
EXPN have to be parsed and 5321 is moderately specific about
their syntax. ... The SMTP extension model clearly allows for
doing just about anything.
Ah yes. Forgot about these and of course, others like AUTH, CHUNKING
are SMTP extension examples of *structured* response text parsing for
client/server negotiated concepts.