usefor-article-11 June 2003
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5.5. Newsgroups
The Newsgroups-header's content specifies the newsgroup(s) in which
the article is intended to appear. It is an inheritable header
(4.2.5.2) which then becomes the default Newsgroups-header of any
followup, unless a Followup-To-header is present to prescribe
otherwise (see 8.6). Articles MUST NOT be passed between relaying
agents or to serving agents unless the sending agent has been
configured to supply and the receiving agent to receive at least one
of the newsgroup-names in the Newsgroups-header.
header =/ Newsgroups-header
Newsgroups-header = "Newsgroups" ":" SP Newsgroups-content
*( ";" extension-parameter )
Newsgroups-content = [FWS] newsgroup-name
*( [FWS] ng-delim [FWS] newsgroup-name )
[FWS]
newsgroup-name = component *( "." component )
component = 1*component-grapheme
ng-delim = ","
component-grapheme = DIGIT / ALPHA / "+" / "-" / "_"
[Maybe some better word for 'grapheme'.]
NOTE: Observe that the syntax does not allow comments within the
Newsgroups-header; this is to simplify processing by relaying
and serving agents which have a requirement to process this
header extremely rapidly.
Components beginning with underline ("_") are reserved for use by
future versions of this standard and MUST NOT occur in newsgroup-
names (whether in Newsgroups-headers or in newgroup control messages
(7.2.1)). However, such names MUST be accepted.
Components beginning with "+" or "-" are reserved for use by
implementations and MUST NOT occur in newsgroup-names (whether in
Newsgroups-headers or in newgroup control messages). Implementors may
assume that this rule will not change in any future version of this
standard.
NOTE: For example, implementors may safely use leading "+" and
"-" to "escape" other entities within something that looks like
a newsgroup-name.
The format of newsgroup-names is ultimately determined by the
policies of those administrative agencies which have the
responsibility for creating new newsgroups within the various
hierarchies of Usenet. There are traditional, social and technical
arguments why there should be restrictions on these formats (and the
force of the technical ones changes over time with developments in
computers and operating systems) Therefore, such administrative
agencies SHOULD establish and promulgate the restrictions they intend
to apply within their own hierarchies.
NOTE: These issues are discussed more fully in [USEAGE]. The
following policy restrictions represent what is considered safe
and appropriate at the present time. Although purely advisory,
hierarchy administrators should consider the consequences
carefully before allowing them to be exceeded. They could also
be taken as the defaults in unmanaged hierarchies.
1. Uppercase letters are forbidden.
2. A component name is forbidden to consist entirely of digits.
3. A component is limited to 30 component-graphemes and a
newsgroup-name to 71 component-graphemes (counting also the
'.'s separating the components).
[There was a suggestion to reduce that 71 to 66 in order to allow such a
newsgoup-name to fit in the on the first line of a Followup-To-header
without exceeding 79 characters.]
Serving and relaying agents MUST accept any syntactially correct
newsgroup-name even if it would violate whatever policy restrictions
may be in place. Posting and injecting agents MAY enforce them (but
only with the explicit agreement of the poster).
The inclusion of folding white space within a Newsgroups-content is a
newly introduced feature in this standard. It MUST be accepted by all
conforming implementations (relaying agents, serving agents and
reading agents). Posting agents should be aware that such postings
may be rejected by overly-critical old-style relaying agents. When a
sufficient number of relaying agents are in conformance, posting
agents SHOULD generate such whitespace in the form of <CRLF WSP> so
as to keep the length of lines in the relevant headers (notably
Newsgroups and Followup-To) to a reasonable length (such as 79
characters, which is likely to be displayed satisfactorily by most
current reading agents). Before such critical mass occurs, injecting
agents MAY reformat such headers by removing whitespace inserted by
the posting agent, but relaying agents MUST NOT do so.
Posters SHOULD use only the names of existing newsgroups in the
Newsgroups-header. However, it is legitimate to cross-post to
newsgroups which do not exist on the posting agent's host, provided
that at least one of the newsgroups DOES exist there. Relaying agents
MUST NOT rewrite Newsgroups-headers in any way, even if some or all
of the newsgroups do not exist on the relaying agent's host. Serving
agents MUST NOT create new newsgroups simply because an unrecognized
newsgroup-name occurs in a Newsgroups-header (see 7.2.1 for the
correct method of newsgroup creation).
The Newsgroups-header is intended for use in Netnews articles rather
than in email messages. It MAY be used in an email message to
indicate that it is a copy also posted to the listed newsgroups, in
which case the inclusion of a Posted-And-Mailed header (6.9) would
also be appropriate. However, it SHOULD NOT be used in an email-only
reply to a Netnews article (thus the "inheritable" property of this
header applies only to followups to a newsgroup, and not to followups
to the poster).
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#Diff to first older
--- ../usefor-article-10/Newsgroups.out April 2003
+++ ../usefor-article-11/Newsgroups.out June 2003
@@ -4,10 +4,10 @@
the article is intended to appear. It is an inheritable header
(4.2.5.2) which then becomes the default Newsgroups-header of any
followup, unless a Followup-To-header is present to prescribe
- otherwise. Articles MUST NOT be passed between relaying agents or to
- serving agents unless the sending agent has been configured to supply
- and the receiving agent to receive at least one of the newsgroup-
- names in the Newsgroups-header.
+ otherwise (see 8.6). Articles MUST NOT be passed between relaying
+ agents or to serving agents unless the sending agent has been
+ configured to supply and the receiving agent to receive at least one
+ of the newsgroup-names in the Newsgroups-header.
header =/ Newsgroups-header
Newsgroups-header = "Newsgroups" ":" SP Newsgroups-content
@@ -20,6 +20,14 @@
ng-delim = ","
component-grapheme = DIGIT / ALPHA / "+" / "-" / "_"
+
+[Maybe some better word for 'grapheme'.]
+
+ NOTE: Observe that the syntax does not allow comments within the
+ Newsgroups-header; this is to simplify processing by relaying
+ and serving agents which have a requirement to process this
+ header extremely rapidly.
+
Components beginning with underline ("_") are reserved for use by
future versions of this standard and MUST NOT occur in newsgroup-
names (whether in Newsgroups-headers or in newgroup control messages
@@ -35,62 +43,38 @@
"-" to "escape" other entities within something that looks like
a newsgroup-name.
- Agencies responsible for the administration of particular hierarchies
- MAY place additional restrictions on the newsgroup-names they allow
- within those hierarchies. Where there is no such specific policy, the
- following restrictions SHOULD be applied to newsgroup-names.
-
- NOTE: These restrictions are intended to reflect existing
- practice, with some additions to accommodate foreseeable
- enhancements, and are intended both to avoid certain technical
- difficulties and to avoid unnecessary confusion. It may well be
- that experience will allow future extensions to this standard to
- relax some or all of these restrictions.
-
- The specific restrictions (to be applied in the absence of
- established policies to the contrary) are:
-
- 1. Uppercase letters are forbidden. Traditionally, newsgroup-names
- have been written in lowercase. Posting agents Ought Not to
- convert uppercase characters to the corresponding lowercase forms
- except under the explicit instructions of the poster.
+ The format of newsgroup-names is ultimately determined by the
+ policies of those administrative agencies which have the
+ responsibility for creating new newsgroups within the various
+ hierarchies of Usenet. There are traditional, social and technical
+ arguments why there should be restrictions on these formats (and the
+ force of the technical ones changes over time with developments in
+ computers and operating systems) Therefore, such administrative
+ agencies SHOULD establish and promulgate the restrictions they intend
+ to apply within their own hierarchies.
+
+ NOTE: These issues are discussed more fully in [USEAGE]. The
+ following policy restrictions represent what is considered safe
+ and appropriate at the present time. Although purely advisory,
+ hierarchy administrators should consider the consequences
+ carefully before allowing them to be exceeded. They could also
+ be taken as the defaults in unmanaged hierarchies.
- 2. A component name is forbidden to consist entirely of digits.
+ 1. Uppercase letters are forbidden.
- NOTE: This requirement was in [RFC 1036] but nevertheless
- several such groups have appeared in practice and implementors
- should be prepared for them. A common implementation technique
- uses each component as the name of a directory and uses numeric
- filenames for each article within a group. Such an
- implementation needs to be careful when this could cause a clash
- (e.g. between article 123 of group xxx.yyy and the directory for
- group xxx.yyy.123).
-
- 3. A component is limited to 30 component-graphemes and a newsgroup-
- name to 71 component-graphemes (counting also the '.'s separating
- the components). Whilst there is no longer any technical reason
- to limit the length of a component (formerly, it was limited to 14
- octets) nor of a newsgroup-name, it should be noted that these
- names are also used in the newsgroups-line (7.2.1.2) where an
- overall policy limit applies and, moreover, excessively long names
- can be exceedingly inconvenient in practical use.
-
- Serving and relaying agents MUST accept any newsgroup-name that meets
- the above requirements, even if it violates one or more of the policy
- restrictions. Posting and injecting agents MAY reject articles
- containing newsgroup-names that do not meet these restrictions, and
- posting agents MAY attempt to correct them (but only with the
- explicit agreement of the poster).
-
- Since future extensions to this standard plus any relaxations of the
- default restrictions introduced by specific hierarchies might
- invalidate some such checks, warnings, and adjustments,
- implementations MUST incorporate means to disable them.
+ 2. A component name is forbidden to consist entirely of digits.
- NOTE: Observe that the syntax does not allow comments within the
- Newsgroups-header; this is to simplify processing by relaying and
- serving agents which have a requirement to process this header
- extremely rapidly.
+ 3. A component is limited to 30 component-graphemes and a
+ newsgroup-name to 71 component-graphemes (counting also the
+ '.'s separating the components).
+[There was a suggestion to reduce that 71 to 66 in order to allow such a
+newsgoup-name to fit in the on the first line of a Followup-To-header
+without exceeding 79 characters.]
+
+ Serving and relaying agents MUST accept any syntactially correct
+ newsgroup-name even if it would violate whatever policy restrictions
+ may be in place. Posting and injecting agents MAY enforce them (but
+ only with the explicit agreement of the poster).
The inclusion of folding white space within a Newsgroups-content is a
newly introduced feature in this standard. It MUST be accepted by all
@@ -100,23 +84,21 @@
sufficient number of relaying agents are in conformance, posting
agents SHOULD generate such whitespace in the form of <CRLF WSP> so
as to keep the length of lines in the relevant headers (notably
- Newsgroups and Followup-To) to no more than than 79 characters (or
- other agreed policy limit - see 4.5). Before such critical mass
- occurs, injecting agents MAY reformat such headers by removing
- whitespace inserted by the posting agent, but relaying agents MUST
- NOT do so.
+ Newsgroups and Followup-To) to a reasonable length (such as 79
+ characters, which is likely to be displayed satisfactorily by most
+ current reading agents). Before such critical mass occurs, injecting
+ agents MAY reformat such headers by removing whitespace inserted by
+ the posting agent, but relaying agents MUST NOT do so.
Posters SHOULD use only the names of existing newsgroups in the
Newsgroups-header. However, it is legitimate to cross-post to
newsgroups which do not exist on the posting agent's host, provided
- that at least one of the newsgroups DOES exist there, and followup
- agents SHOULD accept this (posting agents MAY accept it, but Ought at
- least to alert the poster to the situation and request confirmation).
- Relaying agents MUST NOT rewrite Newsgroups-headers in any way, even
- if some or all of the newsgroups do not exist on the relaying agent's
- host. Serving agents MUST NOT create new newsgroups simply because an
- unrecognized newsgroup-name occurs in a Newsgroups-header (see 7.2.1
- for the correct method of newsgroup creation).
+ that at least one of the newsgroups DOES exist there. Relaying agents
+ MUST NOT rewrite Newsgroups-headers in any way, even if some or all
+ of the newsgroups do not exist on the relaying agent's host. Serving
+ agents MUST NOT create new newsgroups simply because an unrecognized
+ newsgroup-name occurs in a Newsgroups-header (see 7.2.1 for the
+ correct method of newsgroup creation).
The Newsgroups-header is intended for use in Netnews articles rather
than in email messages. It MAY be used in an email message to