[14] 電子ニュースのメッセージ形式 (Usefor)
の頭欄、 Distribution
: 欄には、
そのメッセージの配布範囲 (の希望) を記述します。
たとえば、 Distribution: world は、世界中に配布 (してもよい) ことを表します。 Distribution: local は、局所的に配布して欲しい (そのサイト内だけで、他のサイトには配送して欲しくない) ことを表します。
[15] あまり上手く機能していないので、使われない(使わないようにしようとする) 傾向にあります。
world が既定値的に扱われています。 local が自分のホストだけを指す 名前としてよく使われます。その他の名前は各ホストの設定次第です。
日本では fj.* への投稿で fj という名前が良く使われていましたが、 意味が無いので止めようということになりました (がまだつけている 人もいるとかいないとか)。
draft-usefor-article では先頭に「!」をつけることでその範囲を除外できる としています。
また、「all」の使用を禁じ、配布範囲名は3文字以上とし、 2文字の名前は国名と見なすとしています。
値 | 意味 | 説明・仕様 |
ca | ||
can | カナダ | >>8 |
eunet | EUNET (≒欧州) | |
fj | fj.* 配送範囲 | >>3 |
inet | Internet | |
la | ||
local | local | >>2 |
mtl | Montreal | >>8 |
na | 北米 | >>8 |
nippon | nippon.* 配送範囲 | >>1 |
nj | New Jersey | [RFC 1036] |
ny | [RFC 1036] | |
ont | Ontario | >>10 |
qc | Quebec | >>8 |
to | ||
tor | ||
tx | ||
uk | 連合王国 | |
us | アメリカ合衆国 | usefor-article |
uwo | UWO 関連サイト | >>10 |
world | 全世界 | 既定値。 >>4 |
注: local
に相当する範囲名は上の表には載せていない。
>>5- を参照。
[2] local
は、ローカル・サイトのみ配布します。
投稿したサーバーのみ又は投稿したサーバーの属する組織内のみ配布されるのが普通です。
[3] fj
は、 fj.* に記事を投稿する時に慣習的につけていましたが、
1995〜6年頃意味が無いからやめようと言われだされ、その後徐々に減り、やがて書くことが間違いとされ、今ではほとんど見かけません。
Distribution:
が Newsgroups: のように使われていた時代の名残とも言われています。
(真偽はしらん。)
[12] 米国・カナダの州についてはその2文字略称が使われています。
u-tokai
(東海大学), yunoki
(東海大及び静岡短大)imasy
(imasy.or.jp): UUCPのニュース初期設定ガイド <http://www.imasy.or.jp/faq/txt/INIT_USER_NEWS_SETUP_PROPOSAL>spd
: Linuxの管理を効率的に <http://member.nifty.ne.jp/maaberu/kanri.htm>concordia
(Concordia 大): Netnews: the "Distribution" Header <http://newsflash.concordia.ca/public/faqs/distribution.html>This line is used to alter the distribution scope of the message. It is a comma separated list similar to the "Newsgroups" line. User subscriptions are still controlled by "Newsgroups", but the message is sent to all systems subscribing to the newsgroups on the "Distribution" line in addition to the "Newsgroups" line. For the message to be transmitted, the receiving site must normally receive one of the specified newsgroups AND must receive one of the specified distributions. Thus, a message concerning a car for sale in New Jersey might have headers including:
Newsgroups: rec.auto,misc.forsale Distribution: nj,ny
so that it would only go to persons subscribing to rec.auto or misc. for sale within New Jersey or New York. The intent of this header is to restrict the distribution of a newsgroup further, not to increase it. A local newsgroup, such as nj.crazy-eddie, will probably not be propagated by hosts outside New Jersey that do not show such a newsgroup as valid. A follow-up message should default to the same "Distribution" line as the original message, but the user can change it to a more limited one, or escalate the distribution if it was originally restricted and a more widely distributed reply is appropriate.
The Distribution header is an inheritable header (see 4.2.2.2) which specifies geographical or organizational limits to an article's propagation.
Distribution-content= distribution *( dist-delim distribution ) dist-delim = "," distribution = positive-distribution / negative-distribution positive-distribution = *FWS distribution-name *FWS negative-distribution = *FWS "!" distribution-name *FWS distribution-name = ALPHA 1*distribution-rest distribution-rest = ALPHA / "+" / "-" / "_"
NOTE: The use of ALPHA in the syntax ensures that distribution names are always in US-ASCII.
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 BOTH of (a) at least one of the newsgroups in the article's Newsgroups header, and (b) at least one of the positive-distributions (if any) in the article's Distribution header and none of the negative- distributions. Additionally, reading agents MAY be configured so that unwanted distributions do not get displayed.
NOTE: Although it would seem redundant to filter out unwanted distributions at both ends of a relaying link (and it is clearly more efficient to do so at the sending end), many sending sites have been reluctant, historically speaking, to apply such filters (except to ensure that distributions local to their own site or cooperating subnet did not escape); moreover they tended to configure their filters on an "all but those listed" basis, so that new and hitherto unheard of distributions would not be caught. Indeed many "hub" sites actually wanted to receive all possible distributions so that they could feed on to their clients in all possible geographical (or organizational) regions.
Therefore, it is desirable to provide facilities for rejecting unwanted distributions at the receiving end. Indeed, it may be simpler to do so locally than to inform each sending site of what is required, especially in the case of specialized distributions (for example for control messages, such as cancels from certain issuers) which might need to be added at short notice. Tha possibility for reading agents to filter distributions has been provided for the same reason.
Exceptionally, ALL relaying agents are deemed willing to supply or accept the distribution "world", and NO relaying agent should supply or accept the distribution "local". However, "world" SHOULD NEVER be mentioned explicitly since it is the default when the Distribution header is absent entirely. "All" MUST NOT be used as a distribution-name. Distribution-names SHOULD contain at least three characters, except when they are two-letter country names as in [ISO 3166]. Distribution-names are case-insensitive (i.e. "US", "Us" and "us" all specify the same distribution).
NOTE: "Distribution: !us" can be used to cause an article to go to the whole of "world" except for "us".
Posting agents Ought Not to provide a default Distribution header without giving the poster an opportunity to override it. Followup agents SHOULD initially supply the same Distribution header as found in the precursor.
See RFCのライセンス
[16] RFC 5537 - Netnews Architecture and Protocols ( ( 版)) <http://tools.ietf.org/html/rfc5537#page-15>
[17] RFC 5536 - Netnews Article Format ( ( 版)) <http://tools.ietf.org/html/rfc5536#section-3.2.4>