Subject: Re: RFC2821 and EHLO-specified extensions.
From: [email-masked]
To: [email-masked]
Cc: [email-masked]
Date: Fri, 19 Nov 2004 13:01:50 -0500
List-Id: <ietf-smtp.imc.org>

On Thu, 18 Nov 2004 18:37:09 EST, Bruce Lilly said:

> Incidentally, if you had initially stated that the extension in
> question was AUTH, we could have pointed to RFC 2821 section
> 4.1.1 which specifically addresses command parameters such
> as the one used with MAIL FROM when the AUTH extension is
> in effect.

In the original posting, I *said* I knew that the text for some
verbs covered *that verb*..  It was the "general case" that I didn't see..

As it turns out, the brain damage goes further that I thought.. :)

> An explicit requirement such as the one in RFC 3030 is appropriate
> for BDAT because of the unusual potential for confusion.  Likewise
> for any specific extension with similar potential.  But it's not
> necessary in general because of the server's ability to send a
> negative response.

Consider:  EXPN.  3.5.2 says:

   Since they were both optional in RFC 821, they MUST be listed as
   service extensions in an EHLO response, if they are supported.

OK.. So we're still on the "it has to be in the EHLO" path, right?

However, 4.1.4 says:

   A session that will contain mail transactions MUST first be
   initialized by the use of the EHLO command.  An SMTP server SHOULD
   accept commands for non-mail transactions (e.g., VRFY or EXPN)
   without this initialization.

Gaak. ;)