[NNTP] RFC 4643 user-pass-char question

[Antti-Juhani Kaijanaho]

Hi

RFC 4643 section 3.1 says, in part:

   user-pass-char = B-CHAR

   NOTE: a server implementation MAY parse AUTHINFO USER and AUTHINFO
   PASS specially so as to allow white space to be used within the
   username or password.  Such implementations accept the additional
   syntax (making these two items inconsistent with "token" in Section
   9.8 of [NNTP]):

   user-pass-char =/ SP / TAB


Now, B-CHAR is defined in RFC 3977, section 9.8 as

   B-CHAR     = CTRL / TAB / SP / %x21-FF


It seems to me that the NOTE in 4643 § 3.1, particularly the rule augmenting
user-pass-char is redundant, since SP and TAB are B-CHARs.

My question is, what is this note *intended* to convey?


Draft 9 (June 2005) had P-CHAR instead of B-CHAR.  Draft 10 (August 2005) has
B-CHAR.  The change seems to have been proposed at
http://lists.eyrie.org/pipermail/ietf-nntp/2005-August/005840.html, but its
effect on the NOTE is not discussed.


The question I was trying to resolve by reading the grammar was, is it
permissible (or eve required) for a server to respond with 501 to an AUTHINFO
USER with a username containing spaces.  However, given the above problem, I
am unable to determine the answer from the document itself.

-- 
Antti-Juhani Kaijanaho, Jyväskylä, Finland
http://antti-juhani.kaijanaho.fi/newblog/
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