usefor-article-12 November 2003

4.2.1.  Naming of Headers

   Despite the restrictions on header-name syntax imposed by the
   grammar, relaying, serving and reading agents SHOULD tolerate
   header-names containing any US-ASCII printable character other than
   colon (":", US-ASCII 58).

   Whilst relaying agents MUST accept, and pass on unaltered, any non-
   variant header whose header-name is syntactically correct, and
   reading agents MUST enable them to be displayed, at least optionally,
   posting and injecting agents SHOULD NOT generate headers other than
     o headers established by this standard or any extension to it;
     o those recognized by other IETF-established standards, notably the
       Email standard [RFC 2822] and its extensions, excluding any
       explicitly deprecated for Netnews (e.g. see section 9.2.1 for the
       deprecated Disposition-Notification-To-header); or,
       alternatively, those listed in some future IANA registry of
       recognized headers;
     o experimental headers beginning with "X-" (as defined in 4.2.5.1);
     o on a provisional basis only, headers related to new protocols
       under development which are the subject of (or intended to be the
       subject of) some IETF-approved RFC (whether Informational,
       Experimental or Standards-Track).
   However, software SHOULD NOT attempt to interpret headers not
   specifically intended to be meaningful in the Netnews environment.
[However, if [KLYNE], which defines an IANA registry of recognized
headers, becomes accepted before we are done (which is likely), then
that paragraph can be simplified very considerably.]

   Header-names are case-insensitive. There is a preferred case
   convention set out in [USEAGE], and which is used in the various
   rules defining headers in this standard.  Relaying and reading agents
   MUST, however, tolerate header-names in any case.

--- ../usefor-article-11/Naming_of_Headers.out          June 2003
+++ ../usefor-article-12/Naming_of_Headers.out          November 2003