Subject: #1052 Changes from RFC 2822

From: Harald Tveit Alvestrand <[email-masked]>
Date: Thu, 29 Sep 2005 17:10:43 +0200

Updated text:

Appendix C.  Differences from RFC 2822

   This appendix lists the differences between the syntax allowed by the
   Netnews Article Format (this document) as compared to the Internet
   Message Format, specifically [RFC2822].

   The Netnews article format is a strict subset of the Internet Message
   Format; all Netnews articles conform to the syntax of [RFC2822].

   The following restrictions are important:

      A SP (space) is REQUIRED after the colon (':') following header
      field name.

      A more restricted syntax of msg-id (to be used by the Message-ID,
      References, and Supersedes header fields) is defined.

      The length of a msg-id MUST NOT exceed 250 octets.

      Comments are not allowed in the Message-ID header field.

      The CFWS between msg-ids in the References header field is not
      optional.

      It is legal for a parser to not accept obsolete syntax, except
      that:

         The <obs-phrase> construct MUST be accepted.

         The obsolete timezone "GMT" MUST be accepted in the Date header
         field.

      Every line of a header field body (including the first and any
      that are subsequently folded) MUST contain at least one non-
      whitespace character. This means that an empty header is illegal.

---

From: "Charles Lindsey" <[email-masked]>
Date: Fri, 30 Sep 2005 13:58:18 GMT

>   Message Format, specifically [RFC2822].
                  ^^^^^^^^^^^^^^
		  as specified in

That ensures that we do not actually take a position one way or the other
on the religious question of whether there is such a thing as "THE
Internet Message Format" (some read RFC 2822 as specifying there is;
others read it as applying only within the framework of "electronic
mail").

>      A SP (space) is REQUIRED after the colon (':') following header
                                                               ^
                                                               a

>      A more restricted syntax of msg-id (to be used by the Message-ID,
                                   ^^^^^^
                                  <msg-id>

>      The length of a msg-id MUST NOT exceed 250 octets.
                       ^^^^^^
                      <msg-id>

>      The CFWS between msg-ids in the References header field is not
                        ^^^^^^^
                       <msg-ids>

>         The obsolete timezone "GMT" MUST be accepted in the Date header
                       ^^^^^^^^                        ^^^^^^^^^^^^^^^^^^
                        <zone>                       within a <date-time>
>         field.
          ^^^^^

[Because the same applies also to the Injection-Date and Expires header
fields.]

>      whitespace character. This means that an empty header is illegal.

It might be helpful to add "(consequently, the syntax of <unstructured> is
changed)" [or "now requires at least one character" or somesuch].

The only item you have not included is something on the lines of:

       There is no RECOMMENDED limit of 78 characters in a header line.

[We decided this was a matter of best practice - hence there are advisory
limits in USEAGE].

It might also be useful to mention (but not as a restriction, of course)
that MIME is fully incorporated, at least to the extent given in RFC 2049.

-- 
Charles H. Lindsey ---------At Home, doing my own thing------------------------
Tel: +44 161 436 6131 Fax: +44 161 436 6133   Web: http://www.cs.man.ac.uk/~chl
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