MBOX-Line: From dave at cridland.net  Sun Jan 27 01:24:06 2008
To: imap-protocol@u.washington.edu
From: Dave Cridland <dave@cridland.net>
Date: Fri Jun  8 12:34:41 2018
Subject: [Imap-protocol] example of authentication PLAIN with imap?
In-Reply-To: <alpine.WNT.1.00.0801251607230.3096@Tomobiki-Cho.CAC.Washignton.EDU>
References: <08Jan25.155553pst."58696"@synergy1.parc.xerox.com>
	<alpine.WNT.1.00.0801251607230.3096@Tomobiki-Cho.CAC.Washignton.EDU>
Message-ID: <19909.1201425846.570755@peirce.dave.cridland.net>

On Sat Jan 26 00:22:56 2008, Mark Crispin wrote:
> Last, and absolutely least, RFC 4959 details a way that the initial  
> response can be sent in the AUTHENTICATE command IF, AND ONLY IF,  
> the server allows that facility.  Note that the client is under no  
> obligation to use that facility even if the server allows it.

ACAP always offers this facility, but likewise does not mandate that  
clients avail themselves of it - it cannot, in fact; there's text in  
the SASL base spec saying so. So Mark's note above could be clarified  
  further by adding "[...] and the client understands the extension".  
(That said, where the server offers it and the client does understand  
it, it's likely to be used wherever possible - it's a most trivial  
extension on both ends).

ACAP's challenges and responses are binary, not base64 encoded, so  
it's very often used in SASL mechanism examples for readability,  
since it's the only SASL profile which does this in a text-based  
protocol.

ACAP can also supply completion data on success - a final SASL  
response in the tagged OK response - and I seem to remember seeing  
occasional examples in documents showing IMAP doing the same, but  
I've never found a specification saying so - I suspect this is a case  
of people transcribing examples from ACAP to IMAP in order to use a  
more popular protocol. A minor case of caveat lector - the examples  
can be wrong.

Dave.
-- 
Dave Cridland - mailto:dave@cridland.net - xmpp:dwd@jabber.org
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Infotrope Polymer - ACAP, IMAP, ESMTP, and Lemonade

