Re: [ietf-smtp] SMTP server reply extensions

Ned Freed <ned.freed@mrochek.com> Fri, 10 April 2020 16:13 UTC

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Cc: Timo Sirainen <timo@sirainen.com>, ietf-smtp@ietf.org
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Date: Fri, 10 Apr 2020 09:07:03 -0700 (PDT)
From: Ned Freed <ned.freed@mrochek.com>
In-reply-to: "Your message dated Fri, 10 Apr 2020 08:43:51 -0700 (PDT)" <01RJJBJ305QW000058@mauve.mrochek.com>
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To: Ned Freed <ned.freed@mrochek.com>
Archived-At: <https://mailarchive.ietf.org/arch/msg/ietf-smtp/ffJ6s8fD5QiunVzCCtH4829nMng>
Subject: Re: [ietf-smtp] SMTP server reply extensions
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> I guess I'm missing something pretty fundamental here, because I don't see why
> any of this is necessary.

> We have a model for extending SMTP/LMTP that includes private extensions:
> Advertise the extension in the EHLO/LHO response, then enable the extension
> either with a new command or parameter. There's essentially no limit on what an
> extension can do, and it certainly includes enabling the use of structured
> information in certain replies.

I should also note that the use of an enabling command or parameter here
isn't strictly necessary, especially in the case of LMTP: Since reply text
is normally unstructured, all that's needed is an indicator from the server
that it's going to include structured information in some replies. This
has worked just fine in the case of ENHANCEDSTATUSCODES.

				Ned