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Re: RFC2821 and EHLO-specified extensions.

2004-11-18 08:06:35
On Wed, 17 Nov 2004 18:44:11 EST, Bruce Lilly said:

It takes two to tango...

Probably the client is doing something wrong; the whole point of
negotiation of extensions is to avoid a client sending an unsupported
command (or command parameter).  RFC 2821 section 2.2 and its
subsections discuss the negotiation of extensions.

Yes.  The whole *point* is that nowhere in 2.2 does it *say* that (for example)
the client is in the wrong if it sends a BDAT verb (rfc3030) if the
BDAT extension wasn't listed in the EHLO response.

We all *know* sending that sending a BDAT un-negotiated is wrong - what
brought this up was a thread on a local mailing list where somebody asked
if the EHLO list was authoritative, and I went to reply with the 
chapter-and-verse
and came up empty-handed... ;)

(As an aside, rfc3030 *does* contain language in section 3 that prohibits
sending a BDAT to a server that didn't advertise the extension.  However,
consider an X-FOOBAR extension that adds verbs/parameters, but whose
documentation, if any, doesn't contain similar language....)

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