draft-ietf-usefor-usepro-00.txt   draft-ietf-usefor-usepro-01.txt 
INTERNET-DRAFT Charles H. Lindsey INTERNET-DRAFT Charles H. Lindsey
Usenet Format Working Group University of Manchester Usenet Format Working Group University of Manchester
August 2004 September 2004
News Article Architecture and Protocols News Article Architecture and Protocols
<draft-ietf-usefor-usepro-00.txt> <draft-ietf-usefor-usepro-01.txt>
Status of this Memo Status of this Memo
By submitting this Internet-Draft, I certify that any applicable By submitting this Internet-Draft, I certify that any applicable
patent or other IPR claims of which I am aware have been patent or other IPR claims of which I am aware have been
disclosed, and any of which I become aware will be disclosed, in disclosed, and any of which I become aware will be disclosed, in
accordance with RFC 3668. accordance with RFC 3668.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
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documents at any time. It is inappropriate to use Internet-Drafts documents at any time. It is inappropriate to use Internet-Drafts
as reference material or to cite them other than as "work in as reference material or to cite them other than as "work in
progress." progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire in February 2005. This Internet-Draft will expire in March 2005.
Abstract Abstract
This Draft, together with its companion draft [USEFOR], are This Draft, together with its companion draft [USEFOR], are
intended as standards track documents, together obsoleting RFC intended as standards track documents, together obsoleting RFC
1036, which itself dates from 1987. 1036, which itself dates from 1987.
This Standard defines the architecture of Netnews systems and This Standard defines the architecture of Netnews systems and
specifies the requirements to be met by software which originates, specifies the requirements to be met by software which originates,
distributes, stores and displays Netnews articles. distributes, stores and displays Netnews articles.
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technology is now in widespread use for other purposes. technology is now in widespread use for other purposes.
Backward compatibility has been a major goal of this endeavour, but Backward compatibility has been a major goal of this endeavour, but
where this standard and earlier documents or practices conflict, this where this standard and earlier documents or practices conflict, this
standard should be followed. In most such cases, current practice is standard should be followed. In most such cases, current practice is
already compatible with these changes. already compatible with these changes.
A companion Current Best Practice document [USEAGE], addressing A companion Current Best Practice document [USEAGE], addressing
requirements which are present for Social rather than Normative requirements which are present for Social rather than Normative
News Article Architecture and Protocols August 2004 News Article Architecture and Protocols September 2004
reasons is in preparation. reasons is in preparation.
[The use of the words "this standard" within this document when [The use of the words "this standard" within this document when
referring to itself does not imply that this draft yet has pretensions referring to itself does not imply that this draft yet has pretensions
to be a standard, but rather indicates what will become the case if and to be a standard, but rather indicates what will become the case if and
when it is accepted as an RFC with the status of a proposed or draft when it is accepted as an RFC with the status of a proposed or draft
standard.] standard.]
[Remarks enclosed in square brackets and aligned with the left margin, [Remarks enclosed in square brackets and aligned with the left margin,
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6.2.2.1. Example ........................................... 18 6.2.2.1. Example ........................................... 18
6.2.3. The 'mvgroup' Control Message ......................... 18 6.2.3. The 'mvgroup' Control Message ......................... 18
6.2.3.1. Example ........................................... 19 6.2.3.1. Example ........................................... 19
6.2.4. The 'checkgroups' Control Message ..................... 20 6.2.4. The 'checkgroups' Control Message ..................... 20
6.3. Cancel .................................................... 21 6.3. Cancel .................................................... 21
6.4. Ihave, sendme ............................................. 22 6.4. Ihave, sendme ............................................. 22
6.5. Obsolete control messages. ............................... 24 6.5. Obsolete control messages. ............................... 24
7. Duties of Various Agents ...................................... 24 7. Duties of Various Agents ...................................... 24
7.1. General principles to be followed ......................... 24 7.1. General principles to be followed ......................... 24
News Article Architecture and Protocols August 2004 News Article Architecture and Protocols September 2004
7.2. Duties of an Injecting Agent .............................. 25 7.2. Duties of an Injecting Agent .............................. 25
7.2.1. Proto-articles ........................................ 25 7.2.1. Proto-articles ........................................ 25
7.2.2. Procedure to be followed by Injecting Agents .......... 26 7.2.2. Procedure to be followed by Injecting Agents .......... 26
7.3. Procedure for Forwarding to a Moderator ................... 27 7.2.3. Procedure for Forwarding to a Moderator ............... 28
7.4. Duties of a Relaying Agent ................................ 28 7.3. Duties of a Relaying Agent ................................ 29
7.4.1. Example ............................................... 30 7.3.1. Path-Header Example ................................... 31
7.5. Duties of a Serving Agent ................................. 30 7.4. Duties of a Serving Agent ................................. 32
7.6. Duties of a Posting Agent ................................. 31 7.5. Duties of a Posting Agent ................................. 33
7.7. Duties of a Followup Agent ................................ 32 7.6. Duties of a Followup Agent ................................ 34
7.8. Duties of a Moderator ..................................... 33 7.7. Duties of a Reading Agent ................................. 35
7.9. Duties of a Gateway ....................................... 35 7.8. Duties of a Moderator ..................................... 35
7.9.1. Duties of an Outgoing Gateway ......................... 36 7.9. Duties of a Gateway ....................................... 37
7.9.2. Duties of an Incoming Gateway ......................... 36 7.9.1. Duties of an Outgoing Gateway ......................... 38
7.9.3. Example ............................................... 38 7.9.2. Duties of an Incoming Gateway ......................... 39
8. Security and Related Considerations ........................... 39 7.9.3. Example ............................................... 41
8.1. Leakage ................................................... 39 8. Security and Related Considerations ........................... 42
8.2. Attacks ................................................... 40 8.1. Leakage ................................................... 42
8.2.1. Denial of Service ..................................... 40 8.2. Attacks ................................................... 42
8.2.2. Compromise of System Integrity ........................ 41 8.2.1. Denial of Service ..................................... 42
8.3. Liability ................................................. 42 8.2.2. Compromise of System Integrity ........................ 44
9. IANA Considerations ........................................... 42 8.3. Liability ................................................. 45
10. References ................................................... 43 9. IANA Considerations ........................................... 45
11. Acknowledgements ............................................. 44 10. References ................................................... 45
12. Contact Address .............................................. 44 11. Acknowledgements ............................................. 47
Appendix A.1 - A-News Article Format .............................. 45 12. Contact Address .............................................. 47
Appendix A.2 - Early B-News Article Format ........................ 45 Appendix A.1 - A-News Article Format .............................. 47
Appendix A.3 - Obsolete Control Messages .......................... 46 Appendix A.2 - Early B-News Article Format ........................ 48
Appendix B - Notices .............................................. 46 Appendix A.3 - Obsolete Control Messages .......................... 48
Appendix C - Change Log ........................................... 47 Appendix B - Notices .............................................. 49
Appendix C - Change Log ........................................... 50
News Article Architecture and Protocols August 2004 News Article Architecture and Protocols September 2004
[This draft [USEPRO] and its partner [USEFOR] are an interim stage in [This draft [USEPRO] and its partner [USEFOR] are an interim stage in
the splitting into two parts of the earlier draft [ARTICLE]. There is a the splitting into two parts of the earlier draft [ARTICLE]. There is a
certain amount of material - basic concepts, definitions, etc - which certain amount of material - basic concepts, definitions, etc - which
ultimately need occur in only one of the documents, and further such ultimately need occur in only one of the documents, and further such
material which may not be needed at all (e.g. terms currently defined material which may not be needed at all (e.g. terms currently defined
which in the event may not get used). For the moment, all such material which in the event may not get used). For the moment, all such material
has been retained in the present draft (it being, in any case, easier to has been retained in the present draft (it being, in any case, easier to
take unwanted stuff out than to put new stuff in). It has also to be take unwanted stuff out than to put new stuff in). It has also to be
decided, for such material which is needed by both documents, which one decided, for such material which is needed by both documents, which one
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recognized "hierarchies". Anybody can join (it is simply necessary recognized "hierarchies". Anybody can join (it is simply necessary
to negotiate an exchange of articles with one or more other to negotiate an exchange of articles with one or more other
participating hosts). participating hosts).
A "policy" is a rule intended to facilitate the smooth operation of a A "policy" is a rule intended to facilitate the smooth operation of a
network by establishing parameters which restrict behaviour that, network by establishing parameters which restrict behaviour that,
whilst technically unexceptionable, would nevertheless contravene whilst technically unexceptionable, would nevertheless contravene
some accepted standard of "Good Netkeeping". Since the ultimate some accepted standard of "Good Netkeeping". Since the ultimate
beneficiaries of a network are its human readers, who will be less beneficiaries of a network are its human readers, who will be less
News Article Architecture and Protocols August 2004 News Article Architecture and Protocols September 2004
tolerant of poorly designed interfaces than mere computers, articles tolerant of poorly designed interfaces than mere computers, articles
in breach of established policy can cause considerable annoyance to in breach of established policy can cause considerable annoyance to
their recipients. their recipients.
1.2. Objectives 1.2. Objectives
The purpose of this present standard is to define the overall The purpose of this present standard is to define the overall
architecture and the protocols to be used for Netnews in general, and architecture and the protocols to be used for Netnews in general, and
for Usenet in particular, and to set standards to be followed by for Usenet in particular, and to set standards to be followed by
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A Draft popularly referred to as "Son of 1036" [Son-of-1036] was A Draft popularly referred to as "Son of 1036" [Son-of-1036] was
written in 1994 by Henry Spencer. Much is taken directly from Son of written in 1994 by Henry Spencer. Much is taken directly from Son of
1036, and it is hoped that we have followed its spirit and 1036, and it is hoped that we have followed its spirit and
intentions. intentions.
[It is anticipated that [Son-of-1036] will shortly be published as an [It is anticipated that [Son-of-1036] will shortly be published as an
informational RFC (for purposes of historical documentation only), in informational RFC (for purposes of historical documentation only), in
which case most historical information can be removed from this draft, which case most historical information can be removed from this draft,
including the whole of Appendix A.1 and Appendix A.2.] including the whole of Appendix A.1 and Appendix A.2.]
News Article Architecture and Protocols August 2004 News Article Architecture and Protocols September 2004
2. Definitions, Notations and Conventions 2. Definitions, Notations and Conventions
2.1. Definitions 2.1. Definitions
An "article" is the unit of news, synonymous with an [RFC 2822] An "article" is the unit of news, synonymous with an [RFC 2822]
"message". "message".
A "proto-article" (7.2.1) is one that has been created by a "posting A "proto-article" (7.2.1) is one that has been created by a "posting
agent" but has not yet been injected into a Netnews system system by agent" but has not yet been injected into a Netnews system system by
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A "followup" is an article containing a response to the contents of A "followup" is an article containing a response to the contents of
an earlier article (its "precursor"), or which is otherwise intended an earlier article (its "precursor"), or which is otherwise intended
to be grouped with that article for purposes of display (e.g. as part to be grouped with that article for purposes of display (e.g. as part
of a multipart posting such as a FAQ). of a multipart posting such as a FAQ).
An (email) "address" is the mailbox [RFC 2822] (or more particularly An (email) "address" is the mailbox [RFC 2822] (or more particularly
the addr-spec within that mailbox) which directs the delivery of an the addr-spec within that mailbox) which directs the delivery of an
email to its intended recipient, who is said to "own" that address. email to its intended recipient, who is said to "own" that address.
News Article Architecture and Protocols August 2004 News Article Architecture and Protocols September 2004
An article's "reply address" is the address to which mailed replies An article's "reply address" is the address to which mailed replies
should be sent. This is the address specified in the article's From- should be sent. This is the address specified in the article's From-
header (a-5.2), unless it also has a Reply-To-header (a-6.1). header (a-5.2), unless it also has a Reply-To-header (a-6.1).
A "sender" is the person or software (usually, but not always, the A "sender" is the person or software (usually, but not always, the
same as the poster) responsible for the operation of the posting same as the poster) responsible for the operation of the posting
agent or, which amounts to the same thing, for passing the article to agent or, which amounts to the same thing, for passing the article to
the injecting agent. the injecting agent.
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and passes it on to a "relaying agent" for general distribution. It and passes it on to a "relaying agent" for general distribution. It
is expected to bear some responsibility towards the rest of the is expected to bear some responsibility towards the rest of the
network for the behaviour of its posters (and provision is therefore network for the behaviour of its posters (and provision is therefore
made for it to be easily contactable by email). made for it to be easily contactable by email).
A "relaying agent" is software which receives allegedly compliant A "relaying agent" is software which receives allegedly compliant
articles from injecting agents and/or other relaying agents, and articles from injecting agents and/or other relaying agents, and
possibly passes copies on to other relaying agents and "serving possibly passes copies on to other relaying agents and "serving
agents". agents".
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A "serving agent" receives an article from a relaying agent and files A "serving agent" receives an article from a relaying agent and files
it in a "news database". It also provides an interface for reading it in a "news database". It also provides an interface for reading
agents to access the news database. agents to access the news database.
A "news database" is the set of articles and related structural A "news database" is the set of articles and related structural
information stored by a serving agent and made available for access information stored by a serving agent and made available for access
by reading agents. by reading agents.
A "gateway" is software which receives news articles and converts A "gateway" is software which receives news articles and converts
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Certain words, when capitalized, are used to define the significance Certain words, when capitalized, are used to define the significance
of individual requirements. The key words "MUST", "REQUIRED", of individual requirements. The key words "MUST", "REQUIRED",
"SHOULD", "RECOMMENDED", "MAY" and "OPTIONAL", and any of those words "SHOULD", "RECOMMENDED", "MAY" and "OPTIONAL", and any of those words
associated with the word "NOT", are to be interpreted as described in associated with the word "NOT", are to be interpreted as described in
[RFC 2119]. [RFC 2119].
NOTE: The use of "MUST" or "SHOULD" implies a requirement that NOTE: The use of "MUST" or "SHOULD" implies a requirement that
would or could lead to interoperability problems if not would or could lead to interoperability problems if not
followed. followed.
News Article Architecture and Protocols August 2004 News Article Architecture and Protocols September 2004
NOTE: A requirement imposed on a relaying or serving agent NOTE: A requirement imposed on a relaying or serving agent
regarding some particular article should be understood as regarding some particular article should be understood as
applying only if that article is actually accepted for applying only if that article is actually accepted for
processing (since any agent may always reject any article processing (since any agent may always reject any article
entirely, for reasons of site policy). entirely, for reasons of site policy).
Wherever the context permits, use of the masculine includes the Wherever the context permits, use of the masculine includes the
feminine and use of the singular includes the plural, and vice versa. feminine and use of the singular includes the plural, and vice versa.
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and User-Agent, leading to increased functionality. and User-Agent, leading to increased functionality.
o Provision has been made for almost all headers to have MIME-style o Provision has been made for almost all headers to have MIME-style
parameters (to be ignored if not recognized), thus facilitating parameters (to be ignored if not recognized), thus facilitating
extension of those headers in future standards. extension of those headers in future standards.
o Certain headers and Control messages (a-Appendix A.3 and Appendix o Certain headers and Control messages (a-Appendix A.3 and Appendix
A.3) have been made obsolete. A.3) have been made obsolete.
o Distributions are expected to be checked at the receiving end, as o Distributions are expected to be checked at the receiving end, as
well as the sending end, of a relaying link. well as the sending end, of a relaying link.
o There are numerous other small changes, clarifications and o There are numerous other small changes, clarifications and
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enhancements. enhancements.
3.2. Transitional Arrangements 3.2. Transitional Arrangements
An important distinction must be made between serving and relaying An important distinction must be made between serving and relaying
agents, which are responsible for the distribution and storage of agents, which are responsible for the distribution and storage of
news articles, and user agents, which are responsible for news articles, and user agents, which are responsible for
interactions with users. It is important that the former should be interactions with users. It is important that the former should be
upgraded to conform to this standard as soon as possible to provide upgraded to conform to this standard as soon as possible to provide
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agents. It is not intended, in general, that any single user agents. It is not intended, in general, that any single user
agent will be able to display every charset known to IANA, but agent will be able to display every charset known to IANA, but
all such agents MUST support US-ASCII. Serving and relaying all such agents MUST support US-ASCII. Serving and relaying
agents are not affected. agents are not affected.
o The new Control: mvgroup command will need to be implemented in o The new Control: mvgroup command will need to be implemented in
serving agents. For the benefit of older serving agents it is serving agents. For the benefit of older serving agents it is
therefore RECOMMENDED that it be followed shortly by a therefore RECOMMENDED that it be followed shortly by a
corresponding newgroup command and it MUST always be followed by corresponding newgroup command and it MUST always be followed by
a rmgroup command for the old group after a reasonable overlap a rmgroup command for the old group after a reasonable overlap
News Article Architecture and Protocols August 2004 News Article Architecture and Protocols September 2004
period. An implementation of the mvgroup command as an alias for period. An implementation of the mvgroup command as an alias for
the newgroup command would thus be minimally conforming. User the newgroup command would thus be minimally conforming. User
agents are unaffected. agents are unaffected.
o Provision is made for relaying and serving agents to use the o Provision is made for relaying and serving agents to use the
Date-header in the case of articles injected through existing Date-header in the case of articles injected through existing
agents which do not provide an Injection-Date-header. agents which do not provide an Injection-Date-header.
o All the headers newly introduced by this standard can safely be o All the headers newly introduced by this standard can safely be
ignored by existing software, albeit with loss of the new ignored by existing software, albeit with loss of the new
functionality. functionality.
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"8bit data" [RFC 2045]. Thus raw binary data cannot be "8bit data" [RFC 2045]. Thus raw binary data cannot be
transmitted in an article body except by the use of a Content- transmitted in an article body except by the use of a Content-
Transfer-Encoding such as base64. Transfer-Encoding such as base64.
In particular, transmission paths MUST convey all headers (including In particular, transmission paths MUST convey all headers (including
body part headers and headers within message/rfc822 objects) intact, body part headers and headers within message/rfc822 objects) intact,
even if they contain octets in the range 128 to 255. These even if they contain octets in the range 128 to 255. These
requirements include the transmissiom paths between posting agents, requirements include the transmissiom paths between posting agents,
injecting agents, relaying agents, serving agents and reading agents, injecting agents, relaying agents, serving agents and reading agents,
but NOT the paths traversed by Netnews articles that have been but NOT the paths traversed by Netnews articles that have been
gatewayed into Email (7.8.1). gatewayed into Email (7.9.1).
[At some point it will be necessary for the IMAP standards to catch up [At some point it will be necessary for the IMAP standards to catch up
with these requirements.] with these requirements.]
5. Definition of new Media Types 5. Definition of new Media Types
This standard defines (or redefines) several new Media Types, which This standard defines (or redefines) several new Media Types, which
require to be registered with IANA as provided for in [RFC 2048]. require to be registered with IANA as provided for in [RFC 2048].
5.1. Application/news-transmission 5.1. Application/news-transmission
The Media Type "application/news-transmission" is intended for the The Media Type "application/news-transmission" is intended for the
encapsulation of complete news articles where the intention is that encapsulation of complete news articles where the intention is that
the recipient should then inject them into Netnews. This Application the recipient should then inject them into Netnews. This Application
type provides one of the methods for mailing articles to moderators type provides one of the methods for mailing articles to moderators
(see 7.2.2) and it is also the preferred method when sending to an (see 7.2.2) and it is also the preferred method when sending to an
email-to-news gateway (see 7.8.2). email-to-news gateway (see 7.9.2).
News Article Architecture and Protocols August 2004 News Article Architecture and Protocols September 2004
NOTE: The benefit of such encapsulation is that it removes NOTE: The benefit of such encapsulation is that it removes
possible conflict between news and email headers and it provides possible conflict between news and email headers and it provides
a convenient way of "tunnelling" a news article through a a convenient way of "tunnelling" a news article through a
transport medium that does not support 8bit characters. transport medium that does not support 8bit characters.
The MIME Media Type definition of "application/news-transmission" is: The MIME Media Type definition of "application/news-transmission" is:
MIME type name: application MIME type name: application
MIME subtype name: news-transmission MIME subtype name: news-transmission
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batch format defined in section 6.4 MUST be used. batch format defined in section 6.4 MUST be used.
5.2. Message/news obsoleted 5.2. Message/news obsoleted
The Media Type "message/news", as previously registered with IANA, is The Media Type "message/news", as previously registered with IANA, is
hereby declared obsolete. It was never widely implemented, and its hereby declared obsolete. It was never widely implemented, and its
default treatment as "application/octet-stream" by agents that did default treatment as "application/octet-stream" by agents that did
not recognize it was counter productive. The Media Type not recognize it was counter productive. The Media Type
"message/rfc822" SHOULD be used in its place. "message/rfc822" SHOULD be used in its place.
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5.3. Application/news-groupinfo 5.3. Application/news-groupinfo
The "application/news-groupinfo" is used in conjunction with the The "application/news-groupinfo" is used in conjunction with the
"newgroup" (6.2.1) and "mvgroup" (6.2.3) control messages. The "newgroup" (6.2.1) and "mvgroup" (6.2.3) control messages. The
newsgroup-name in the newsgroups-line MUST agree with the newsgroup- newsgroup-name in the newsgroups-line MUST agree with the newsgroup-
name in the "newgroup" or "mvgroup" control message. The Media Type name in the "newgroup" or "mvgroup" control message. The Media Type
"application/news-groupinfo" MUST NOT be used except as a part of "application/news-groupinfo" MUST NOT be used except as a part of
such control messages. such control messages.
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newsgroup-description newsgroup-description
= utext *( *WSP utext ) = utext *( *WSP utext )
moderation-flag = %x28.4D.6F.64.65.72.61.74.65.64.29 moderation-flag = %x28.4D.6F.64.65.72.61.74.65.64.29
; case sensitive "(Moderated)" ; case sensitive "(Moderated)"
The newsgroup-description MUST NOT contain any occurrence of the The newsgroup-description MUST NOT contain any occurrence of the
string "(Moderated)" within it. Although optional, the newsgroups- string "(Moderated)" within it. Although optional, the newsgroups-
tag SHOULD be included until such time as this standard has been tag SHOULD be included until such time as this standard has been
widely adopted, to ensure compatibility with present practice. widely adopted, to ensure compatibility with present practice.
News Article Architecture and Protocols August 2004 News Article Architecture and Protocols September 2004
Moderated newsgroups MUST be marked by appending the case sensitive Moderated newsgroups MUST be marked by appending the case sensitive
text " (Moderated)" at the end. It is NOT recommended that the text " (Moderated)" at the end. It is NOT recommended that the
moderator's email address be included in the newsgroup-description as moderator's email address be included in the newsgroup-description as
has sometimes been done. has sometimes been done.
NOTE: There is no provision for the use of charsets other than NOTE: There is no provision for the use of charsets other than
US-ASCII within a newsgroup-description. Such a facility may be US-ASCII within a newsgroup-description. Such a facility may be
provided in a future extension to this standard. provided in a future extension to this standard.
[That may seem harsh, but if we make any such provision now, it will [That may seem harsh, but if we make any such provision now, it will
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The following sections document the control messages. "Message" is The following sections document the control messages. "Message" is
used herein as a synonym for "article" unless context indicates used herein as a synonym for "article" unless context indicates
otherwise. otherwise.
The descriptions below set out REQUIREMENTS to be followed by sites The descriptions below set out REQUIREMENTS to be followed by sites
that receive control messages and choose to honour them. However, that receive control messages and choose to honour them. However,
nothing in these descriptions should be taken as overriding the right nothing in these descriptions should be taken as overriding the right
of any such site, in accordance with its local policy, to refuse to of any such site, in accordance with its local policy, to refuse to
honour any particular control message, or to refer it to an honour any particular control message, or to refer it to an
News Article Architecture and Protocols August 2004 News Article Architecture and Protocols September 2004
administrator for approval (either as a class or on a case-by-case administrator for approval (either as a class or on a case-by-case
basis). basis).
Relaying Agents MUST propagate all control messages regardless of Relaying Agents MUST propagate all control messages regardless of
whether or not they are recognized or processed locally. whether or not they are recognized or processed locally.
In the following sections, each type of control message is defined In the following sections, each type of control message is defined
syntactically by defining its verb, its arguments, and possibly its syntactically by defining its verb, its arguments, and possibly its
body. body.
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be acted on outside of those subnets. be acted on outside of those subnets.
NOTE: Specifically, some alternative flags such as "y" and "m", NOTE: Specifically, some alternative flags such as "y" and "m",
which are sent and recognized by some current software, are NOT which are sent and recognized by some current software, are NOT
part of this standard. Moreover, some existing implementations part of this standard. Moreover, some existing implementations
treat any flag other than "moderated" as indicating an treat any flag other than "moderated" as indicating an
unmoderated newsgroup. Both of these usages are contrary to this unmoderated newsgroup. Both of these usages are contrary to this
standard and control messages with such non-standard flags standard and control messages with such non-standard flags
should be ignored. should be ignored.
News Article Architecture and Protocols August 2004 News Article Architecture and Protocols September 2004
6.2.1.1. The Body of the 'newgroup' Control Message 6.2.1.1. The Body of the 'newgroup' Control Message
The body of the newgroup message contains the following subparts, The body of the newgroup message contains the following subparts,
preferably in the order shown: preferably in the order shown:
1. An "application/news-groupinfo" part (5.3) containing the name and 1. An "application/news-groupinfo" part (5.3) containing the name and
newsgroups-line of the group. This part MUST be present and SHOULD newsgroups-line of the group. This part MUST be present and SHOULD
be used to update any copy of the newsgroups-line (5.3) maintained be used to update any copy of the newsgroups-line (5.3) maintained
by the serving agent. by the serving agent.
skipping to change at page 17, line 5 skipping to change at page 17, line 5
The proto-article SHOULD be injected at the serving agent that The proto-article SHOULD be injected at the serving agent that
processes the control message AFTER the newsgroup in question has processes the control message AFTER the newsgroup in question has
been created or modified. It MUST NOT be injected if the newsgroup been created or modified. It MUST NOT be injected if the newsgroup
is not, in fact, created (for whatever reason). It MUST NOT be is not, in fact, created (for whatever reason). It MUST NOT be
submitted to any relaying agent for transmission beyond the serving submitted to any relaying agent for transmission beyond the serving
agent(s) upon which the newsgroup creation has just been effected (in agent(s) upon which the newsgroup creation has just been effected (in
other words, it is to be treated as having a "Distribution: local" other words, it is to be treated as having a "Distribution: local"
header, whether such a header is actually present or not). header, whether such a header is actually present or not).
News Article Architecture and Protocols August 2004 News Article Architecture and Protocols September 2004
NOTE: It is not precluded that the proto-article is itself a NOTE: It is not precluded that the proto-article is itself a
control message or other type of special article, to be control message or other type of special article, to be
activated only upon creation of the new newsgroup. However, activated only upon creation of the new newsgroup. However,
except as might arise from that possibility, any except as might arise from that possibility, any
"application/news-transmission" within some nested "multipart/*" "application/news-transmission" within some nested "multipart/*"
structure within the proto-article is not to be activated. structure within the proto-article is not to be activated.
6.2.1.3. Example 6.2.1.3. Example
skipping to change at page 18, line 5 skipping to change at page 18, line 5
6.2.2. The 'rmgroup' Control Message 6.2.2. The 'rmgroup' Control Message
control-message =/ Rmgroup-message control-message =/ Rmgroup-message
Rmgroup-message = "rmgroup" Rmgroup-arguments Rmgroup-message = "rmgroup" Rmgroup-arguments
Rmgroup-arguments = CFWS newsgroup-name Rmgroup-arguments = CFWS newsgroup-name
The "rmgroup" control message requests that the specified group be The "rmgroup" control message requests that the specified group be
removed from the list of valid groups. The Media Type of the body is removed from the list of valid groups. The Media Type of the body is
unspecified; it MAY contain anything, usually an explanatory text. unspecified; it MAY contain anything, usually an explanatory text.
News Article Architecture and Protocols August 2004 News Article Architecture and Protocols September 2004
NOTE: It is entirely proper for a serving agent to retain the NOTE: It is entirely proper for a serving agent to retain the
group until all the articles in it have expired, provided that group until all the articles in it have expired, provided that
it ceases to accept new articles. it ceases to accept new articles.
6.2.2.1. Example 6.2.2.1. Example
From: "example.all Administrator" <admin@noc.example> From: "example.all Administrator" <admin@noc.example>
Newsgroups: example.admin.obsolete, example.admin.announce Newsgroups: example.admin.obsolete, example.admin.announce
Date: 4 Apr 2002 22:04 -0900 (PST) Date: 4 Apr 2002 22:04 -0900 (PST)
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after a suitable overlap period to allow the network to adjust to the after a suitable overlap period to allow the network to adjust to the
new arrangement. new arrangement.
At the same time as a serving agent acts upon this message, all At the same time as a serving agent acts upon this message, all
injecting agents associated with that serving agent SHOULD inhibit injecting agents associated with that serving agent SHOULD inhibit
the posting of new articles to the old group (preferably with some the posting of new articles to the old group (preferably with some
indication to the poster that the new group should have been used). indication to the poster that the new group should have been used).
Relaying agents, however, MUST continue to propagate such articles Relaying agents, however, MUST continue to propagate such articles
during the overlap period. during the overlap period.
News Article Architecture and Protocols August 2004 News Article Architecture and Protocols September 2004
NOTE: It is to be expected that different serving agents will NOTE: It is to be expected that different serving agents will
act on this message at different points of time, users of the act on this message at different points of time, users of the
old group will have to become accustomed to the new arrangement, old group will have to become accustomed to the new arrangement,
and followups to already established threads will likely and followups to already established threads will likely
continue under the old group. Therefore, there needs to be an continue under the old group. Therefore, there needs to be an
overlap period during which articles may continue to be accepted overlap period during which articles may continue to be accepted
by relaying and serving agents in either group. This standard by relaying and serving agents in either group. This standard
does not specify any standard period of overlap (though it would does not specify any standard period of overlap (though it would
be expected to be expressed in days rather than in months). The be expected to be expressed in days rather than in months). The
skipping to change at page 20, line 5 skipping to change at page 20, line 5
hierarchy. Note that the "mvgroup" control message is not really hierarchy. Note that the "mvgroup" control message is not really
intended to be used for merging two existing groups. intended to be used for merging two existing groups.
6.2.3.1. Example 6.2.3.1. Example
From: "example.all Administrator" <admin@noc.example> From: "example.all Administrator" <admin@noc.example>
Newsgroups: example.oldgroup,example.newgroup,example.admin.announce Newsgroups: example.oldgroup,example.newgroup,example.admin.announce
Date: 30 Apr 2002 22:04 -0500 (EST) Date: 30 Apr 2002 22:04 -0500 (EST)
Subject: cmsg mvgroup example.oldgroup example.newgroup moderated Subject: cmsg mvgroup example.oldgroup example.newgroup moderated
News Article Architecture and Protocols August 2004 News Article Architecture and Protocols September 2004
Message-ID: <mvgroup-example.oldgroup-20020430@noc.example> Message-ID: <mvgroup-example.oldgroup-20020430@noc.example>
Approved: admin@noc.example Approved: admin@noc.example
Control: mvgroup example.oldgroup example.newgroup moderated Control: mvgroup example.oldgroup example.newgroup moderated
MIME-Version: 1.0 MIME-Version: 1.0
Content-Type: multipart/mixed; boundary=nxt Content-Type: multipart/mixed; boundary=nxt
--nxt --nxt
Content-Type: application/news-groupinfo Content-Type: application/news-groupinfo
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chkscope = 1*( CFWS ["!"] newsgroup-name ) chkscope = 1*( CFWS ["!"] newsgroup-name )
chksernr = CFWS "#" 1*DIGIT chksernr = CFWS "#" 1*DIGIT
A "checkgroups" message applies to any (sub-)hierarchy with a prefix A "checkgroups" message applies to any (sub-)hierarchy with a prefix
listed in the chkscope parameter, provided that the rightmost listed in the chkscope parameter, provided that the rightmost
matching newsgroup-name in the list is not immediately preceded by a matching newsgroup-name in the list is not immediately preceded by a
"!". If no chkscope parameter is given, it applies to all "!". If no chkscope parameter is given, it applies to all
hierarchies for which group statements appear in the body of the hierarchies for which group statements appear in the body of the
message. message.
News Article Architecture and Protocols August 2004 News Article Architecture and Protocols September 2004
NOTE: Some existing software does not support the "chkscope" NOTE: Some existing software does not support the "chkscope"
parameter. Thus a "checkgroups" message SHOULD also contain the parameter. Thus a "checkgroups" message SHOULD also contain the
groups of other subhierarchies the sender is not responsible groups of other subhierarchies the sender is not responsible
for. "New" software MUST ignore groups which do not fall within for. "New" software MUST ignore groups which do not fall within
the chkscope parameter of the "checkgroups" message. the chkscope parameter of the "checkgroups" message.
The chksernr parameter is a serial number, which can be any positive The chksernr parameter is a serial number, which can be any positive
integer (e.g. just numbered or the date in YYYYMMDD). It SHOULD integer (e.g. just numbered or the date in YYYYMMDD). It SHOULD
increase by an arbitrary value with every change to the group list increase by an arbitrary value with every change to the group list
skipping to change at page 22, line 5 skipping to change at page 22, line 5
be withdrawn from circulation or access. be withdrawn from circulation or access.
control-message =/ Cancel-message control-message =/ Cancel-message
Cancel-message = "cancel" Cancel-arguments Cancel-message = "cancel" Cancel-arguments
Cancel-arguments = CFWS msg-id [CFWS] Cancel-arguments = CFWS msg-id [CFWS]
The argument identifies the article to be cancelled by its message The argument identifies the article to be cancelled by its message
identifier. The body SHOULD contain an indication of why the identifier. The body SHOULD contain an indication of why the
cancellation was requested. The cancel message SHOULD be posted to cancellation was requested. The cancel message SHOULD be posted to
News Article Architecture and Protocols August 2004 News Article Architecture and Protocols September 2004
the same newsgroup, with the same distribution, as the article it is the same newsgroup, with the same distribution, as the article it is
attempting to cancel. attempting to cancel.
A serving agent that elects to honour a cancel message SHOULD make A serving agent that elects to honour a cancel message SHOULD make
the article unavailable for relaying or serving (perhaps by deleting the article unavailable for relaying or serving (perhaps by deleting
it completely). If the target article is unavailable, and the it completely). If the target article is unavailable, and the
acceptability of the cancel message cannot be established without it, acceptability of the cancel message cannot be established without it,
activation of the cancel message SHOULD be delayed until the target activation of the cancel message SHOULD be delayed until the target
article has been seen. See also sections 7.3 and 7.4. article has been seen. See also sections 7.3 and 7.4.
skipping to change at page 22, line 27 skipping to change at page 22, line 27
NOTE: It is expected that the security extension envisaged in NOTE: It is expected that the security extension envisaged in
section a-7.1 will make more detailed provisions for section a-7.1 will make more detailed provisions for
establishing whether honouring a particular cancel message is in establishing whether honouring a particular cancel message is in
order. In particular, it is likely that there will be provision order. In particular, it is likely that there will be provision
for the digital signature of 3rd party cancels (i.e. those for the digital signature of 3rd party cancels (i.e. those
issued other than by the sender, the moderator, or the issued other than by the sender, the moderator, or the
injector). injector).
NOTE: A cancel submitted by the poster for an article in a NOTE: A cancel submitted by the poster for an article in a
moderated group will be forwarded to the moderator of that moderated group will be forwarded to the moderator of that
group, and it is up to that moderator to act upon it (7.7). group, and it is up to that moderator to act upon it (7.8).
NOTE: The former requirement [RFC 1036] that the From and/or NOTE: The former requirement [RFC 1036] that the From and/or
Sender-headers of the cancel message should match those of the Sender-headers of the cancel message should match those of the
original article has been removed from this standard, since it original article has been removed from this standard, since it
only encouraged cancel issuers to conceal their true identity, only encouraged cancel issuers to conceal their true identity,
and it was not usually checked or enforced by canceling and it was not usually checked or enforced by canceling
software. Therefore, both the From and/or Sender-headers and software. Therefore, both the From and/or Sender-headers and
any Approved-header should now relate to the entity responsible any Approved-header should now relate to the entity responsible
for issuing the cancel message. for issuing the cancel message.
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control-message =/ Ihave-message control-message =/ Ihave-message
Ihave-message = "ihave" Ihave-arguments Ihave-message = "ihave" Ihave-arguments
Ihave-arguments = relayer-name Ihave-arguments = relayer-name
control-message =/ Sendme-message control-message =/ Sendme-message
Sendme-message = "sendme" Sendme-arguments Sendme-message = "sendme" Sendme-arguments
Sendme-arguments = Ihave-arguments Sendme-arguments = Ihave-arguments
relayer-name = path-identity ; see a-5.6.1 relayer-name = path-identity ; see a-5.6.1
ihave-body = *( msg-id CRLF ) ihave-body = *( msg-id CRLF )
News Article Architecture and Protocols August 2004 News Article Architecture and Protocols September 2004
sendme-body = ihave-body sendme-body = ihave-body
The body of the message consists of a list of msg-ids, one per line. The body of the message consists of a list of msg-ids, one per line.
[RFC 1036] also permitted the list of msg-ids to appear in the Ihave- [RFC 1036] also permitted the list of msg-ids to appear in the Ihave-
or Sendme-arguments with the syntax or Sendme-arguments with the syntax
Ihave-arguments = [FWS] *( msg-id FWS ) [relayer-name] Ihave-arguments = [FWS] *( msg-id FWS ) [relayer-name]
but this form SHOULD NOT now be used, though relaying agents MAY but this form SHOULD NOT now be used, though relaying agents MAY
recognize and process it for backward compatibility. recognize and process it for backward compatibility.
skipping to change at page 24, line 5 skipping to change at page 24, line 5
first component of a newsgroup-name). The control message SHOULD then first component of a newsgroup-name). The control message SHOULD then
be delivered ONLY to the relaying agent(s) identified by that be delivered ONLY to the relaying agent(s) identified by that
relayer-name, and any relaying agent receiving such a message which relayer-name, and any relaying agent receiving such a message which
includes its own relayer-name MUST NOT propagate it further. Each includes its own relayer-name MUST NOT propagate it further. Each
pair of relaying agent(s) sending and receiving these messages MUST pair of relaying agent(s) sending and receiving these messages MUST
be immediate neighbors, exchanging news directly with each other. be immediate neighbors, exchanging news directly with each other.
Each relaying agent advertises its new arrivals to the other using Each relaying agent advertises its new arrivals to the other using
ihave messages, and each uses sendme messages to request the articles ihave messages, and each uses sendme messages to request the articles
it lacks. it lacks.
News Article Architecture and Protocols August 2004 News Article Architecture and Protocols September 2004
To reduce overhead, ihave and sendme messages SHOULD be sent To reduce overhead, ihave and sendme messages SHOULD be sent
relatively infrequently and SHOULD contain reasonable numbers of relatively infrequently and SHOULD contain reasonable numbers of
message identifiers. If ihave and sendme are being used to implement message identifiers. If ihave and sendme are being used to implement
a backup feed, it may be desirable to insert a delay between a backup feed, it may be desirable to insert a delay between
reception of an ihave and generation of a sendme, so that a slightly reception of an ihave and generation of a sendme, so that a slightly
slow primary feed will not cause large numbers of articles to be slow primary feed will not cause large numbers of articles to be
requested unnecessarily via sendme. requested unnecessarily via sendme.
6.5. Obsolete control messages. 6.5. Obsolete control messages.
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Be liberal in what you accept, and conservative in what you Be liberal in what you accept, and conservative in what you
send. send.
However, in the case of news there is an even more important However, in the case of news there is an even more important
principle, derived from a much older code of practice, the principle, derived from a much older code of practice, the
Hippocratic Oath (we may thus call this the Hippocratic Principle): Hippocratic Oath (we may thus call this the Hippocratic Principle):
First, do no harm. First, do no harm.
News Article Architecture and Protocols August 2004 News Article Architecture and Protocols September 2004
It is VITAL to realize that decisions which might be merely It is VITAL to realize that decisions which might be merely
suboptimal in a smaller context can become devastating mistakes when suboptimal in a smaller context can become devastating mistakes when
amplified by the actions of thousands of hosts within a few minutes. amplified by the actions of thousands of hosts within a few minutes.
In the case of gateways, the primary corollary to this is: In the case of gateways, the primary corollary to this is:
Cause no loops. Cause no loops.
7.2. Duties of an Injecting Agent 7.2. Duties of an Injecting Agent
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by a relaying agent (7.3). by a relaying agent (7.3).
In exceptional circumstances (e.g. as part of some complex gatewaying In exceptional circumstances (e.g. as part of some complex gatewaying
process, or where a relaying agent considers it essential for process, or where a relaying agent considers it essential for
fulfilling its responsibility towards the rest of the network) an fulfilling its responsibility towards the rest of the network) an
already injected article MAY be "reinjected" into the network. This already injected article MAY be "reinjected" into the network. This
standard does not prescribe any such circumstance; rather this is a standard does not prescribe any such circumstance; rather this is a
matter of policy to be determined by the administrators of each matter of policy to be determined by the administrators of each
injecting agent, who have the responsibility to ensure that no harm injecting agent, who have the responsibility to ensure that no harm
arises. In all other circumstances, unintented reinjection is to be arises. In all other circumstances, unintented reinjection is to be
avoided (see 7.8). Nevertheless, in order to preserve the integrity avoided (see 7.9). Nevertheless, in order to preserve the integrity
of the network in these special cases, this standard sets out the of the network in these special cases, this standard does set out the
correct way to reinject. correct way to reinject.
It is usual for an injecting agent to be closely associated with a It is usual for an injecting agent to be closely associated with a
serving agent, thus giving it access to the list (7.4) showing the serving agent, thus giving it access to the list (7.4) showing the
moderation status of the newsgroups it is likely to handle. In the moderation status of the newsgroups it is likely to handle. In the
event that it does not have such an associated serving agent, it MUST event that it does not have such an associated serving agent, it MUST
maintain that list itself. maintain that list itself.
7.2.1. Proto-articles 7.2.1. Proto-articles
A proto-article SHOULD NOT be propagated in that form to other than A proto-article SHOULD NOT be propagated in that form to other than
injecting agents. injecting agents.
A proto-article has the same format as a normal article except that A proto-article has the same format as a normal article except that
some of the following mandatory headers MAY be omitted: Message-Id- some of the following mandatory headers MAY be omitted: Message-Id-
header, Date-header, Path-header (and even From-header if the header, Date-header, Path-header (and even From-header if the
particular injecting agent can derive that information from other particular injecting agent can derive that information from other
sources). However, if it is intended to offer the proto-article to sources). However, if it is intended to offer the proto-article to
News Article Architecture and Protocols August 2004 News Article Architecture and Protocols September 2004
two or more injecting agents in parallel, then it is only the Path- two or more injecting agents in parallel, then it is only the Path-
header that MAY be omitted. The headers that can be omitted MUST NOT header that MAY be omitted. The headers that can be omitted MUST NOT
contain invalid values; they MUST either be correct or not present at contain invalid values; they MUST either be correct or not present at
all. all.
[Maybe omit that last sentence.] [Maybe omit that last sentence.]
NOTE: An article that is offered for reinjection has, by NOTE: An article that is offered for reinjection has, by
definition, already been injected once, and is not therefore to definition, already been injected once, and is not therefore to
be considered as a proto-article. Hence a genuine proto-article be considered as a proto-article. Hence a genuine proto-article
skipping to change at page 26, line 56 skipping to change at page 26, line 56
likewise with any NNTP-Posting-Date-header). It MAY when likewise with any NNTP-Posting-Date-header). It MAY when
reinjecting, but only if there is no Injection-Date-header reinjecting, but only if there is no Injection-Date-header
present, reject any article whose Date-header appears to be stale present, reject any article whose Date-header appears to be stale
(e.g. more than 72 hours into the past). (e.g. more than 72 hours into the past).
4. It MUST reject any article that does not have the correct 4. It MUST reject any article that does not have the correct
mandatory headers for a proto-article (or, when reinjecting, all mandatory headers for a proto-article (or, when reinjecting, all
the mandatory headers other than Injection-Date), or which the mandatory headers other than Injection-Date), or which
contains any header that does not have legal contents. It SHOULD contains any header that does not have legal contents. It SHOULD
reject any article which contains any header deprecated for reject any article which contains any header deprecated for
Netnews (a-4.2.1). Netnews (a-4.2.1). It SHOULD reject any article whose
Newsgroups-header does not contain at least one newsgroup-name for
an existing group (as listed by its associated serving agent) and
it MAY reject any newsgroup-name which, although syntactically
correct, violates a policy restriction established, for some
News Article Architecture and Protocols September 2004
(sub-)hierarchy, by an agency with the appropriate authority
(1.2). Observe that crossposting to unknown newsgroups is not
precluded provided at least one of those in the Newsgroups-header
is listed.
NOTE: This ability to reject newsgroup-names in breach of
established policy does not extend to relaying agents, though it
might be reasonable for posting agents to do it.
5. If the article is rejected (for reasons given above, or for other 5. If the article is rejected (for reasons given above, or for other
formatting errors or matters of site policy) the posting agent formatting errors or matters of site policy) the posting agent
SHOULD be informed (such as via an NNTP 44x response code) that SHOULD be informed (such as via an NNTP 44x response code) that
News Article Architecture and Protocols August 2004
posting has failed and the article MUST NOT then be processed posting has failed and the article MUST NOT then be processed
further. further.
6. The Message-ID, Date and From-headers (and their contents) MUST be 6. The Message-ID, Date and From-headers (and their contents) MUST be
added when not already present (but that situation could not arise added when not already present (but that situation could not arise
during reinjection). during reinjection). A User-Agent-header MAY be added (or an
already present User-Agent-header MAY be augmented) so as to
identify the software (e.g. "INN/1.7.2") used by the injecting
agent.
7. The injecting agent MUST NOT alter the body of the article in any 7. The injecting agent MUST NOT alter the body of the article in any
way. It MAY, except when reinjecting, add other headers not way (including any change of Content-Transfer-Encoding). It MAY,
already provided by the poster, but SHOULD NOT alter, delete, or except when reinjecting, add other headers not already provided by
reorder any existing header, with the specific exception of the poster, but SHOULD NOT alter, delete, or reorder any existing
"tracing" headers such as Injection-Info and Complaints-To, which header, with the specific exception of "tracing" headers such as
are to be removed as already mentioned. Injection-Info and Complaints-To, which are to be removed as
already mentioned. It MAY also, as an interim measure pending
widespread adoption of the newly introduced (a-5.5) folding
whitespace, reformat the Newsgroups- and any Followup-To-header by
removing any such whitespace inserted by the posting agent.
8. If the Newsgroups-header contains one or more moderated groups and 8. If the Newsgroups-header contains one or more moderated groups and
the article does NOT contain an Approved-header, the injecting the article does NOT contain an Approved-header, the injecting
agent MUST forward it to a moderator as specified in section 7.2.3 agent MUST forward it to a moderator as specified in section 7.2.3
below. below.
9. Otherwise, a Path-header with a tail-entry (a-5.6.3) MUST be 9. Otherwise, a Path-header with a tail-entry (a-5.6.3) MUST be
correctly added if not already present. During reinjection, the correctly added if not already present. During reinjection, the
existing Path-header SHOULD be retained. existing Path-header SHOULD be retained.
10.It MUST then prepend the path-identity of the injecting agent and 10.It MUST then prepend the path-identity of the injecting agent and
a '%' path-delimiter (which serves to separate the pre-injection a '%' path-delimiter (which serves to separate the pre-injection
and post-injection regions of the Path-content) to the Path- and post-injection regions of the Path-content) to the Path-
content; moreover, that path-identity MUST be an FQDN mailable content; this SHOULD then be followed by CRLF and WSP if it would
address. This could result in more that one '%' path-delimiter in otherwise result in a line longer than 79 characters. The
prepended path-identity MUST be an FQDN mailable address (a-
5.6.2). This could result in more that one '%' path-delimiter in
the case of reinjection. See a-5.6.4 for the significance of the the case of reinjection. See a-5.6.4 for the significance of the
various path-delimiters. various path-delimiters.
News Article Architecture and Protocols September 2004
11.An Injection-Info-header (a-6.19) SHOULD be added, identifying the 11.An Injection-Info-header (a-6.19) SHOULD be added, identifying the
trusted source of the article, and a suitable Complaints-To-header trusted source of the article, and a suitable Complaints-To-header
(a-6.20) MAY be added. (a-6.20) MAY be added. Each injecting agent SHOULD use a
consistent form of the Injection-Info-header for all articles
emanating from the same or similar origins.
12.The injecting agent MUST then add an An Injection-Date-header (a- NOTE: The step above is the only place in which an Injection-
5.7) if one is not already present, but it MUST NOT alter, or Info- or Complaints-To-header is to be created. It follows that
remove, an already present Injection-Date-header (and likewise these headers MUST NOT be created, replaced, changed or deleted
SHOULD NOT alter, or remove, an already present NNTP-Posting- by any other agent (except during reinjection, in which case
Date-header). Finally, it forwards the article to one or more they will always relate to the latest injection and can, to that
relaying or serving agents, and the injection process is to be extent, be regarded as variant headers).
considered complete.
7.3. Procedure for Forwarding to a Moderator 12.The injecting agent MUST then add an Injection-Date-header (a-5.7)
if one is not already present, but it MUST NOT alter, or delete,
an already present Injection-Date-header (and likewise SHOULD NOT
alter, or delete, an already present NNTP-Posting-Date-header).
Finally, it forwards the article to one or more relaying or
serving agents, and the injection process is to be considered
complete.
NOTE: The step above is the only place where an Injection-Date-
header is to be created It follows that it MUST NOT subsequently
be replaced, changed or deleted by any other agent, even during
reinjection.
7.2.3. Procedure for Forwarding to a Moderator
An injecting agent forwards ar article to a moderator as follows: An injecting agent forwards ar article to a moderator as follows:
1. It MUST forward it to the moderator of the first (leftmost) 1. It MUST forward it to the moderator of the first (leftmost)
moderated group listed in the Newsgroups-header via email (see 7.7 moderated group listed in the Newsgroups-header via email (see 7.8
for how that moderator may forward it to further moderators). for how that moderator may forward it to further moderators).
There are two possibilities for doing this: There are two possibilities for doing this:
News Article Architecture and Protocols August 2004
(a) The complete article is encapsulated (headers and all) within (a) The complete article is encapsulated (headers and all) within
the email, preferably using the Content-Type the email, preferably using the Content-Type
"application/news-transmission" (5.1) with any usage "application/news-transmission" (5.1) with any usage
parameter set to "moderate". Moreover, there SHOULD NOT be parameter set to "moderate". Moreover, there SHOULD NOT be
more than one encapsulated article within the one email. more than one encapsulated article within the one email.
This method has the advantage of removing any possible This method has the advantage of removing any possible
conflict between Netnews and Email headers, or of changes to conflict between Netnews and Email headers, or of changes to
those headers during transport through email. those headers during transport through email.
(b) The article is sent as an email as it stands, with the (b) The article is sent as an email as it stands, with the
addition of such extra headers (e.g. a To-header) as are addition of such extra headers (e.g. a To-header) as are
necessary for an email. necessary for an email. The existing Message-ID-header SHOULD
be retained.
Although both of these methods have seen use in the past, the Although both of these methods have seen use in the past, the
preponderance of current usage on Usenet has been for method (b) preponderance of current usage on Usenet has been for method (b)
and many moderators are ill-prepared to deal with method (a). and many moderators are ill-prepared to deal with method (a).
Therefore, method (a) SHOULD NOT be used until such time as the Therefore, method (a) SHOULD NOT be used until such time as the
majority of moderators are able to accept it. majority of moderators are able to accept it.
News Article Architecture and Protocols September 2004
2. This standard does not prescribe how the email address of the 2. This standard does not prescribe how the email address of the
moderator is to be determined, that being a matter of policy to be moderator is to be determined, that being a matter of policy to be
arranged by the agency responsible for the oversight of each arranged by the agency responsible for the oversight of each
hierarchy. Nevertheless, there do exist various agents worldwide hierarchy. Nevertheless, there do exist various agents worldwide
which provide the service of forwarding to moderators, and the which provide the service of forwarding to moderators, and the
address to use with them is obtained as follows: address to use with them is obtained as follows:
(a) Each '.' in the newsgroup-name is replaced with a '-'. (a) Each '.' in the newsgroup-name is replaced with a '-'.
(b) The result of these operations is used as the local-part of (b) The result of these operations is used as the local-part of
the mailbox of the agent. For example, articles intended for the mailbox of the agent. For example, articles intended for
"news.announce.important" would be emailed to "news- "news.announce.important" would be emailed to "news-
announce-important@forwardingagent.example". announce-important@forwardingagent.example".
7.4. Duties of a Relaying Agent 7.3. Duties of a Relaying Agent
A Relaying Agent accepts injected articles from injecting and other A Relaying Agent accepts injected articles from injecting and other
relaying agents and passes them on to relaying or serving agents relaying agents and passes them on to relaying or serving agents
according to mutually agreed policy. Relaying agents SHOULD accept according to mutually agreed policy. Relaying agents SHOULD accept
articles ONLY from trusted agents. articles ONLY from trusted agents.
An article SHOULD NOT be relayed unless the sending agent has been
configured to supply and the receiving agent to receive at least one
of the newsgroup-names in its Newsgroups-header and at least one of
the distributions in its Distribution-header, if any. 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".
[That SHOULD has been demoted from a MUST in draft-13. Any objections?]
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. The possibility for reading agents to filter
distributions has been provided (7.7) for the same reason.
News Article Architecture and Protocols September 2004
An article SHOULD NOT be relayed if the path-identity of the
receiving agent (or some known alias thereof) appears in its Path-
header, and the receiving agent MAY detect whether its own path-
identity is already present in the Path-content so as to avoid
further unnecessary relaying.
[See related remarks under serving agents.]
A relaying agent processes articles as follows: A relaying agent processes articles as follows:
1. It MUST establish the trusted identity of the source of the 1. It MUST establish the trusted identity of the source of the
article and compare it with the leftmost path-identity of the article and compare it with the leftmost path-identity of the
Path-content. If it matches it MUST then prepend its own path- Path-content. If it matches it MUST then prepend its own path-
identity and a '/' path-delimiter to the Path-header. If it does identity and a '/' path-delimiter to the Path-content; this SHOULD
not match then it prepends instead two entries to the Path- then be followed by CRLF and WSP if it would otherwise result in a
content; firstly the true established path-identity of the source line longer than 79 characters. If it does not match then it
followed by a '?' path-delimiter, and then, to the left of that, prepends instead two entries to the Path-content; firstly the true
its own path-identity followed by a '/' path-delimiter as usual. established path-identity of the source followed by a '?' path-
This prepending of two entries SHOULD NOT be done if the provided delimiter, and then, to the left of that, its own path-identity
and established identities match. See a-5.6.4 for the followed by a '/' path-delimiter as usual. This prepending of two
significance of the various path-delimiters. entries SHOULD NOT be done if the provided and established
identities match. See a-5.6.4 for the significance of the various
News Article Architecture and Protocols August 2004 path-delimiters.
NOTE: In order to prevent overloading, relaying agents should NOTE: In order to prevent overloading, relaying agents should
not routinely query an external entity (such as a DNS-server) in not routinely query an external entity (such as a DNS-server) in
order to verify an article (though a local cache of the required order to verify an article (though a local cache of the required
information might usefully be consulted). information might usefully be consulted).
2. It MUST examine the Injection-Date-header (or, if that is absent, 2. It MUST examine the Injection-Date-header (or, if that is absent,
the Date-header) and reject the article as stale (a-5.7) if that the Date-header) and reject the article as stale (a-5.7) if that
predates the earliest articles of which it normally keeps record, predates the earliest articles of which it normally keeps record,
or if it is more than 24 hours into the future (the margin MAY be or if it is more than 24 hours into the future (the margin MAY be
less than that 24 hours). less than that 24 hours).
3. It MUST reject any article that does not have the correct 3. It MUST reject any article that does not have the correct
mandatory headers (section a-5) present with legal contents. mandatory headers (section a-5) present with legal contents.
4. It SHOULD reject any article whose optional headers (section a-6) 4. It SHOULD reject any article whose optional headers (section a-6)
do not have legal contents. do not have legal contents.
[Is that too strong? Are relaying agents really expected to check
headers in that detail? I suggest s/SHOULD/MAY/. Even the MUST in Step 4
for mandatory headers might be demoted to SHOULD.]
5. It SHOULD reject any article that has already been sent to it (a 5. It SHOULD reject any article that has already been sent to it (a
database of message identifiers of recent messages is usually kept database of message identifiers of recent messages is usually kept
and matched against). and matched against).
6. It SHOULD reject any article that matches an already received 6. It SHOULD reject any article that matches an already received
cancel message (or an equivalent Supersedes-header) issued by its cancel message (or an equivalent Supersedes-header) issued by its
poster or by some other trusted entity. poster or by some other trusted entity.
7. It MAY reject any article without an Approved-header posted to 7. It MAY reject any article without an Approved-header posted to
newsgroups known to be moderated (this practice is strongly newsgroups known to be moderated (this practice is strongly
recommended, but the information necessary to do so may not be recommended, but the information necessary to do so may not be
News Article Architecture and Protocols September 2004
available to all agents). available to all agents).
8. Finally, it passes articles which match mutually agreed criteria 8. It MAY delete any Xref-header that is present.
on to neighbouring relaying and serving agents. However, it SHOULD
NOT forward articles to sites whose path-identity is already in
the Path-header.
NOTE: It is usual for relaying and serving agents to restrict 9. Finally, it passes the articles on to neighbouring relaying and
the Newsgroups, Distributions, age and size of articles that serving agents.
they wish to receive.
If the article is rejected as being invalid, unwanted or unacceptable If the article is rejected as being invalid, unwanted or unacceptable
due to site policy, the agent that passed the article to the relaying due to site policy, the agent that passed the article to the relaying
agent SHOULD be informed (such as via an NNTP 43x response code) that agent SHOULD be informed (such as via an NNTP 43x response code) that
relaying failed. In order to prevent a large number of error messages relaying failed. In order to prevent a large number of error messages
being sent to one location, relaying agents MUST NOT inform any other being sent to one location, relaying agents MUST NOT inform any other
external entity that an article was not relayed UNLESS that external external entity that an article was not relayed UNLESS that external
entity has explicitly requested that it be informed of such errors. entity has explicitly requested that it be informed of such errors.
Relaying agents MUST NOT alter, delete or rearrange any part of an Relaying agents MUST NOT alter, delete or rearrange any part of an
article expect for headers designated as variant (a-4.2.5.3). article expect for headers designated as variant (a-4.2.5.3). In
particular
News Article Architecture and Protocols August 2004 o they MUST NOT create or augment a User-Agent-header in order to
identify themselves;
o they MUST NOT rewrite the Newsgroups-header in any way, even if
some supposedly non-existent newsgroup is included;
o they MUST NOT refold any header (i.e. they must pass on the
folding as received), even to remove FWS from a Newsgroups-
header;
o they MUST NOT alter the Date-header or the Injection-Date-header;
o they MUST NOT delete any unrecognized header whose header-name is
syntactically correct (whether or not it is registered with IANA
[RFC 3864]);
o they MUST NOT change the Content-Transfer-Encoding of the body or
any body part.
7.4.1. Example 7.3.1. Path-Header Example
Path: foo.isp.example/ Path: foo.isp.example/
foo-server/bar.isp.example?10.123.12.2/old.site.example! foo-server/bar.isp.example?10.123.12.2/old.site.example!
barbaz/baz.isp.example%dialup123.baz.isp.example!not-for-mail barbaz/baz.isp.example%dialup123.baz.isp.example!not-for-mail
NOTE: That article was injected into the news stream by NOTE: That article was injected into the news stream by
baz.isp.example (complaints may be addressed to baz.isp.example (complaints may be addressed to
abuse@baz.isp.example). The injector has taken care to record abuse@baz.isp.example). The injector has taken care to record
that it got it from dialup123.baz.isp.example. "not-for-mail" is that it got it from dialup123.baz.isp.example. "not-for-mail" is
a dummy tail-entry, though sometimes a real userid is put there. a dummy tail-entry, though sometimes a real userid is put there.
The article was relayed, perhaps by UUCP, to the machine known, The article was relayed, perhaps by UUCP, to the machine known,
at least to old.site.example, as "barbaz". at least to old.site.example, as "barbaz".
Barbaz relayed it to old.site.example, which does not yet Barbaz relayed it to old.site.example, which does not yet
conform to this standard (hence the '!' path-delimiter). So one conform to this standard (hence the '!' path-delimiter). So one
cannot be sure that it really came from barbaz. cannot be sure that it really came from barbaz.
News Article Architecture and Protocols September 2004
Old.site.example relayed it to a site claiming to have the IP Old.site.example relayed it to a site claiming to have the IP
address [10.123.12.2], and claiming (by using the '/' path- address [10.123.12.2], and claiming (by using the '/' path-
delimiter) to have verified that it came from old.site.example. delimiter) to have verified that it came from old.site.example.
[10.123.12.2] relayed it to "foo-server" which, not being [10.123.12.2] relayed it to "foo-server" which, not being
convinced that it truly came from [10.123.12.2], did a reverse convinced that it truly came from [10.123.12.2], did a reverse
lookup on the actual source and concluded it was known as lookup on the actual source and concluded it was known as
bar.isp.example (that is not to say that [10.123.12.2] was not a bar.isp.example (that is not to say that [10.123.12.2] was not a
correct IP address for bar.isp.example, but simply that that correct IP address for bar.isp.example, but simply that that
connection could not be substantiated by foo-server). Observe connection could not be substantiated by foo-server). Observe
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"foo-server" is a locally significant name within the complex "foo-server" is a locally significant name within the complex
site of many machines run by foo.isp.example, so the latter site of many machines run by foo.isp.example, so the latter
should have no problem recognizing foo-server and using a '/' should have no problem recognizing foo-server and using a '/'
path-delimiter. Presumably foo.isp.example then delivered the path-delimiter. Presumably foo.isp.example then delivered the
article to its direct clients. article to its direct clients.
It appears that foo.isp.example and old.site.example decided to It appears that foo.isp.example and old.site.example decided to
fold the line, on the grounds that it seemed to be getting a fold the line, on the grounds that it seemed to be getting a
little too long. little too long.
7.5. Duties of a Serving Agent 7.4. Duties of a Serving Agent
A Serving Agent takes an article from a relaying or injecting agent A Serving Agent takes an article from a relaying or injecting agent
and files it in a "news database". It also provides an interface for and files it in a "news database". It also provides an interface for
reading agents to access the news database. This database is normally reading agents to access the news database. This database is normally
indexed by newsgroup with articles in each newsgroup identified by an indexed by newsgroup with articles in each newsgroup identified by an
article-locator (usually in the form of a decimal number - see a- article-locator (usually in the form of a decimal number - see a-
6.16). 6.16).
A serving agent MUST maintain a list showing the moderation status A serving agent MUST maintain a list of the newsgroups it stores in
(see 6.2.1) of the newsgroups it stores in the news database, and its news database showing the moderation status of each one (see
SHOULD include in that list all groups likely to be crossposted to 6.2.1), and SHOULD include in that list all groups likely to be
from those groups (e.g. all other groups in the same hierarchy(ies)). crossposted to from those groups (e.g. all other groups in the same
hierarchy(ies)).
News Article Architecture and Protocols August 2004
NOTE: Since control messages are often of interest, but should NOTE: Since control messages are often of interest, but should
not be displayed as normal articles in regular newsgroups, it is not be displayed as normal articles in regular newsgroups, it is
common for serving agents to make them available in a pseudo- common for serving agents to make them available in a pseudo-
newsgroup named "control" or in a pseudo-newsgroup in a sub- newsgroup named "control" or in a pseudo-newsgroup in a sub-
hierarchy under "control." (e.g. "control.cancel"). hierarchy under "control." (e.g. "control.cancel").
A serving agent MAY decline to accept an article if its own path-
identity is already present in the Path-content or if the Path-
content contains some path-identity whose articles the serving agent
does not want, as a matter of local policy.
[That has been changed from a-5.6.1 in previous drafts, where it said "A
relaying agent MAY decline...". That seemed plain wrong to me. It is
fine for a relaying agent to ignore articles which have apparently
already passed through it (and I still say that), but surely it is for
serving agents to "reject" for policy reasons, and to which the NOTE
below would apply. Comments?]
News Article Architecture and Protocols September 2004
NOTE: This last facility is sometimes used to detect and decline
control messages (notably cancel messages) which have been
deliberately seeded with a path-identity to be "aliased out" by
sites not wishing to act upon them.
[Again, is this "aliasing out" usually detected by the serving agent, or
does it more usually work because the previous relaying agent will never
have sent it in the first place?]
A serving agent processes articles as follows: A serving agent processes articles as follows:
1. It MUST establish the trusted identity of the source of the 1. It MUST establish the trusted identity of the source of the
article and modify the Path-header as for a relaying agent (7.3). article and modify the Path-header as for a relaying agent (7.3).
2. It MUST examine the Injection-Date-header (or, if that is absent, 2. It MUST examine the Injection-Date-header (or, if that is absent,
the Date-header) and reject the article as stale (a-5.7) if that the Date-header) and reject the article as stale (a-5.7) if that
predates the earliest articles of which it normally keeps record, predates the earliest articles of which it normally keeps record,
or if it is more than 24 hours into the future (the margin MAY be or if it is more than 24 hours into the future (the margin MAY be
less than that 24 hours). less than that 24 hours).
3. It MUST reject any article that does not have the correct 3. It MUST reject any article that does not have the correct
mandatory headers (section a-5) present, or which contains any mandatory headers (section a-5) present, or which contains any
header that does not have legal contents. header that does not have legal contents.
4. It SHOULD reject any article that has already been sent to it (a 4. It SHOULD reject any article that has already been sent to it (a
database of message identifiers of recent messages is usually kept database of message identifiers of recent articles is usually kept
and matched against). and matched against).
5. It SHOULD reject any article that matches an already received 5. It SHOULD reject any article that matches an already received
cancel message (or an equivalent Supersedes-header) issued by its cancel message (or an equivalent Supersedes-header) issued by its
poster or by some other trusted entity. poster or by some other trusted entity.
6. It MUST reject any article without an Approved-header posted to 6. It MUST reject any article without an Approved-header posted to
any newsgroup listed as moderated. any newsgroup listed as moderated.
7. It MUST remove any Xref-header (a-6.16) from each article. It 7. It MUST remove any Xref-header (a-6.16) from each article. It
then MAY (and usually will) generate a fresh Xref-header. then MAY (and usually will) generate a fresh Xref-header.
8. Finally, it stores the article in its news database. 8. Finally, it stores the article in its news database.
7.6. Duties of a Posting Agent Serving agents MUST NOT create new newsgroups simply because an
unrecognized newsgroup-name occurs in a Newsgroups-header (see a-
7.2.1 for the correct method of newsgroup creation).
Serving agents MUST NOT alter, delete or rearrange any part of an
article in any other way. The list of particular cases given for
relaying agents (7.3) applies here also.
7.5. Duties of a Posting Agent
A Posting Agent is used to assist the poster in creating a valid A Posting Agent is used to assist the poster in creating a valid
proto-article and forwarding it to an injecting agent. proto-article and forwarding it to an injecting agent.
News Article Architecture and Protocols September 2004
Postings agents SHOULD ensure that proto-articles they create are Postings agents SHOULD ensure that proto-articles they create are
valid according to [USEFOR] and other applicable policies. In valid according to [USEFOR] and other applicable policies. In
particular, they MUST NOT create any Injection-Date-, Injection-Info- particular, they MUST NOT create any Injection-Date-, Injection-Info-
or Complaints-To-header. or Complaints-To-header.
Posting agents meant for use by ordinary posters SHOULD reject any Posting agents meant for use by ordinary posters SHOULD reject any
attempt to post an article which cancels or Supersedes another attempt to post an article which cancels or Supersedes another
article of which the poster is not the author. article of which the poster is not the author.
News Article Architecture and Protocols August 2004 7.6. Duties of a Followup Agent
7.7. Duties of a Followup Agent
A Followup Agent is a special case of a posting agent, and as such is A Followup Agent is a special case of a posting agent, and as such is
bound by all the posting agent's requirements. Followup agents MUST bound by all the posting agent's requirements. Followup agents MUST
create valid followups and are subject to special requirements create valid followups and are subject to special requirements
involving certain inheritable (a-4.2.5.2) and other headers. involving certain inheritable (a-4.2.5.2) and other headers.
Wherever in the following it is stated that, "by default", a header Wherever in the following it is stated that, "by default", a header
is to be taken from some header in the precursor, it means that its is to be taken from some header in the precursor, it means that its
initial content (plus its extension-parameters, if any) are to be initial content (plus its extension-parameters, if any) are to be
copied from those of that precursor header. However, posters MAY copied from those of that precursor header. However, posters MAY
then override that default before posting if they so wish. then override that default before posting if they so wish.
skipping to change at page 32, line 52 skipping to change at page 35, line 4
below) plus the precursor's message identifier appended to the end below) plus the precursor's message identifier appended to the end
of the list (separated from it by CFWS). of the list (separated from it by CFWS).
Followup agents MAY trim References-headers which have grown to Followup agents MAY trim References-headers which have grown to
excessive length, but the first and last message identifiers from excessive length, but the first and last message identifiers from
the precursor MUST NOT be removed. the precursor MUST NOT be removed.
5. If the precursor contains a Mail-Copies-To-header (a-6.8), the 5. If the precursor contains a Mail-Copies-To-header (a-6.8), the
actions to be taken, in accordance with the Mail-Copies-To- actions to be taken, in accordance with the Mail-Copies-To-
content, (and subject to manual override by the poster) are as content, (and subject to manual override by the poster) are as
News Article Architecture and Protocols September 2004
follows: follows:
"nobody" (or when the header is absent) "nobody" (or when the header is absent)
The followup agent SHOULD NOT email a copy of a posted The followup agent SHOULD NOT email a copy of a posted
followup to the poster of the precursor. followup to the poster of the precursor.
"poster" "poster"
The followup agent SHOULD (if it has the necessary The followup agent SHOULD (if it has the necessary
capability) email a copy of a posted followup, which MUST capability) email a copy of a posted followup, which MUST
News Article Architecture and Protocols August 2004
then be sent to the address(es) in the Reply-To-header, and then be sent to the address(es) in the Reply-To-header, and
in the absence of that to the address(es) in the From- in the absence of that to the address(es) in the From-
header. header.
a copy-addr a copy-addr
The followup agent SHOULD likewise email a copy of a posted The followup agent SHOULD likewise email a copy of a posted
followup, which MUST then be sent to the copy-addr. followup, which MUST then be sent to the copy-addr.
When emailing a copy, the followup agent SHOULD also include a When emailing a copy, the followup agent SHOULD also include a
"Posted-And-Mailed: yes" header (a-6.9). "Posted-And-Mailed: yes" header (a-6.9).
Followup agents SHOULD NOT attempt to send email to any address Followup agents SHOULD NOT attempt to send email to any address
ending in ".invalid". ending in ".invalid".
7.7. Duties of a Reading Agent
A reading agent downloads articles from a serving agent, as directed
by the reader, and displays them (or processes them in some other
manner). The article as displayed MUST be identical to the article
as originally posted, subject only to limitations of the display
device (such as availability of charsets, etc.). It MUST provide
facilities for decoding any Content-Transfer-Encodings, encoded-
words, etc., but SHOULD also have the capability to show the article
exactly as received.
It MAY present lists of articles available for display, and MAY
structure those lists so as to show the relationships between the
articles, as determined by the References-, Subject-, Date- and
other-headers (see [USEAGE] for some usual methods of doing this). It
MAY also be configured so that unwanted distributions (a-6.6) are
ignored.
7.8. Duties of a Moderator 7.8. Duties of a Moderator
A Moderator receives news articles by email, decides whether to A Moderator receives news articles by email, decides whether to
accept them and, if so, either injects them into the news stream or accept them and, if so, either injects them into the news stream or
forwards them to further moderators. forwards them to further moderators.
Articles will be received by the moderator either encapsulated as an Articles will be received by the moderator either encapsulated as an
object of Content-Type application/news-transmission (or possibly object of Content-Type application/news-transmission (or possibly
encapsulated but without an explicit Content-Type-header), or else encapsulated but without an explicit Content-Type-header), or else
directly as an email already containing all the headers appropriate directly as an email already containing all the headers appropriate
for a Netnews article (see 7.2.2). Moderators SHOULD be prepared to for a Netnews article (see 7.2.2). Moderators SHOULD be prepared to
accept articles in either format. accept articles in either format.
News Article Architecture and Protocols September 2004
A moderator processes an article, as submitted to any newsgroup that A moderator processes an article, as submitted to any newsgroup that
he moderates, as follows: he moderates, as follows:
1. He decides, on the basis of whatever moderation policy applies to 1. He decides, on the basis of whatever moderation policy applies to
his group, whether to accept or reject the article. He MAY do this his group, whether to accept or reject the article. He MAY do this
manually, or else partially or wholly with the aid of appropriate manually, or else partially or wholly with the aid of appropriate
software for whose operation he is then responsible. If the software for whose operation he is then responsible. If the
article is a cancel nessage (6.3) issued by the poster of an article is a cancel nessage (6.3) issued by the poster of an
earlier article, then he is expected to cancel that earlier earlier article, then he is expected to cancel that earlier
article (in which case there is no more to be done). He MAY article (in which case there is no more to be done). He MAY
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If the article is rejected, then it normally fails for all the If the article is rejected, then it normally fails for all the
newsgroups for which it was intended. If it is accepted, the newsgroups for which it was intended. If it is accepted, the
moderator proceeds with the following steps. moderator proceeds with the following steps.
2. If the Newsgroups-header contains further moderated newsgroups for 2. If the Newsgroups-header contains further moderated newsgroups for
which approval has not already been given, he adds an indication which approval has not already been given, he adds an indication
(identifying both himself and the name of the group) that he (identifying both himself and the name of the group) that he
approves the article, and then forwards it to the moderator of the approves the article, and then forwards it to the moderator of the
leftmost unapproved group (which, if this standard has been leftmost unapproved group (which, if this standard has been
followed correctly, will generally be the next moderated group to followed correctly, will generally be the next moderated group to
News Article Architecture and Protocols August 2004
the right of his own). There are two ways to do this: the right of his own). There are two ways to do this:
(a) He emails it to the submission address of the next moderator (a) He emails it to the submission address of the next moderator
(see section 7.2.2 for the proper method of doing this), or (see section 7.2.2 for the proper method of doing this), or
(b) he rotates the newsgroup-names in the Newsgroups-header to (b) he rotates the newsgroup-names in the Newsgroups-header to
the left so that the targeted group is the leftmost moderated the left so that the targeted group is the leftmost moderated
group in that header, and injects it as below (thus causing group in that header, and injects it as below (thus causing
the injecting agent to email it to the correct moderator). the injecting agent to email it to the correct moderator).
However, he MUST first ensure that the article contains no However, he MUST first ensure that the article contains no
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is sometimes used for this purpose). The approval may also be is sometimes used for this purpose). The approval may also be
confirmed with some form of digital signature (a-7.1). confirmed with some form of digital signature (a-7.1).
3. If the Newsgroups-header contains no further unapproved moderated 3. If the Newsgroups-header contains no further unapproved moderated
groups, he adds an Approved-header (a-6.14) identifying himself groups, he adds an Approved-header (a-6.14) identifying himself
and, insofar as is possible, all the other moderators who have and, insofar as is possible, all the other moderators who have
approved the article. He thus assumes responsibility for having approved the article. He thus assumes responsibility for having
ensured that the article was acceptable to the moderators of all ensured that the article was acceptable to the moderators of all
the moderated groups involved. the moderated groups involved.
News Article Architecture and Protocols September 2004
4. The Date-header SHOULD be retained. Any Injection-Date-header 4. The Date-header SHOULD be retained. Any Injection-Date-header
already present (though there should be none) MUST be removed. already present (though there should be none) MUST be removed.
Exceptionally, if it is known that the injecting agent does not Exceptionally, if it is known that the injecting agent does not
yet support the Injection-Date-header and the Date-header appears yet support the Injection-Date-header and the Date-header appears
to be stale (a-5.7) for reasons understood by the moderator (e.g. to be stale (a-5.7) for reasons understood by the moderator (e.g.
delays in the moderation process) he MAY substitute the current delays in the moderation process) he MAY substitute the current
date. The Message-ID-header SHOULD also be retained unless it is date. The Message-ID-header SHOULD also be retained unless it is
obviously non-compliant with this standard. obviously non-compliant with this standard.
NOTE: A message identifier created by a conforming posting or NOTE: A message identifier created by a conforming posting or
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5.6.3). Any Injection-Info-header (a-6.19) or Complaints-To- 5.6.3). Any Injection-Info-header (a-6.19) or Complaints-To-
header (a-6.20) SHOULD be removed (and if they are not, the header (a-6.20) SHOULD be removed (and if they are not, the
injecting agent will do so, as required in 7.2.2). injecting agent will do so, as required in 7.2.2).
6. He then causes the article to be injected, having first observed 6. He then causes the article to be injected, having first observed
all the duties of a posting agent. all the duties of a posting agent.
NOTE: This standard does not prescribe how the moderator or NOTE: This standard does not prescribe how the moderator or
moderation policy for each newsgroup is established; rather it moderation policy for each newsgroup is established; rather it
assumes that whatever agencies are responsible for the relevant assumes that whatever agencies are responsible for the relevant
News Article Architecture and Protocols August 2004
network or hierarchy (1.1) will have made appropriate network or hierarchy (1.1) will have made appropriate
arrangements in that regard. arrangements in that regard.
7.9. Duties of a Gateway 7.9. Duties of a Gateway
A Gateway transforms an article into the native message format of A Gateway transforms an article into the native message format of
another medium, or translates the messages of another medium into another medium, or translates the messages of another medium into
news articles. Encapsulation of a news article into a message of MIME news articles. Encapsulation of a news article into a message of MIME
type application/news-transmission, or the subsequent undoing of that type application/news-transmission, or the subsequent undoing of that
encapsulation, is not gatewaying, since it involves no transformation encapsulation, is not gatewaying, since it involves no transformation
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The primary dictat for a gateway is: The primary dictat for a gateway is:
Above all, prevent loops. Above all, prevent loops.
Transformation of an article into another medium stands a very high Transformation of an article into another medium stands a very high
chance of discarding or interfering with the protection inherent in chance of discarding or interfering with the protection inherent in
the news system against duplicate articles. The most common problem the news system against duplicate articles. The most common problem
caused by gateways is "spews," gateway loops that cause previously caused by gateways is "spews," gateway loops that cause previously
posted articles to be reinjected repeatedly into Usenet. To prevent posted articles to be reinjected repeatedly into Usenet. To prevent
this, a gateway MUST take precautions against loops, as detailed this, a gateway MUST take precautions against loops, as detailed
News Article Architecture and Protocols September 2004
below. below.
If bidirectional gatewaying (both an incoming and an outgoing If bidirectional gatewaying (both an incoming and an outgoing
gateway) is being set up between Netnews and some other medium, the gateway) is being set up between Netnews and some other medium, the
incoming and outgoing gateways SHOULD be coordinated to avoid incoming and outgoing gateways SHOULD be coordinated to avoid
unintended reinjection of gated articles. Circular gatewaying unintended reinjection of gated articles. Circular gatewaying
(gatewaying a message into another medium and then back into Netnews) (gatewaying a message into another medium and then back into Netnews)
SHOULD NOT be done; encapsulation of the article SHOULD be used SHOULD NOT be done; encapsulation of the article SHOULD be used
instead where this is necessary. instead where this is necessary.
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It is worth noting that safe bidirectional gatewaying between a It is worth noting that safe bidirectional gatewaying between a
mailing list and a newsgroup is far easier if the newsgroup is mailing list and a newsgroup is far easier if the newsgroup is
moderated. Posts to the moderated group and submissions to the moderated. Posts to the moderated group and submissions to the
mailing list can then go through a single point that does the mailing list can then go through a single point that does the
necessary gatewaying and then sends the message out to both the necessary gatewaying and then sends the message out to both the
newsgroup and the mailing list at the same time, eliminating most of newsgroup and the mailing list at the same time, eliminating most of
the possibility of loops. Bidirectional gatewaying between a mailing the possibility of loops. Bidirectional gatewaying between a mailing
list and an unmoderated newsgroup, in contrast, is difficult to do list and an unmoderated newsgroup, in contrast, is difficult to do
correctly and is far more fragile. correctly and is far more fragile.
News Article Architecture and Protocols August 2004
Newsgroups intended to be bidirectionally gated to a mailing list Newsgroups intended to be bidirectionally gated to a mailing list
SHOULD therefore be moderated where possible, even if the moderator SHOULD therefore be moderated where possible, even if the moderator
is a simple gateway and injecting agent that correctly handles is a simple gateway and injecting agent that correctly handles
crossposting to other moderated groups and otherwise passes all crossposting to other moderated groups and otherwise passes all
traffic. traffic.
7.9.1. Duties of an Outgoing Gateway 7.9.1. Duties of an Outgoing Gateway
From the perspective of Netnews, an outgoing gateway is just a From the perspective of Netnews, an outgoing gateway is just a
special type of reading agent. The exact nature of what the outgoing special type of reading agent. The exact nature of what the outgoing
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In general, the following practices are recommended for all outgoing In general, the following practices are recommended for all outgoing
gateways, regardless of whether there is known to be a related gateways, regardless of whether there is known to be a related
incoming gateway, both as a precautionary measure and as a guideline incoming gateway, both as a precautionary measure and as a guideline
to quality of implementation. to quality of implementation.
1. The message identifier of the news article should be preserved if 1. The message identifier of the news article should be preserved if
at all possible, preferably as or within the corresponding unique at all possible, preferably as or within the corresponding unique
identifier of the other medium, but if not at least as a comment identifier of the other medium, but if not at least as a comment
in the message. This helps greatly with preventing loops. in the message. This helps greatly with preventing loops.
News Article Architecture and Protocols September 2004
2. The Date and Injection-Date of the news article should also be 2. The Date and Injection-Date of the news article should also be
preserved if possible, for similar reasons. preserved if possible, for similar reasons.
3. The message should be tagged in some way so as to prevent its 3. The message should be tagged in some way so as to prevent its
reinjection into Netnews. This may be impossible to do without reinjection into Netnews. This may be impossible to do without
knowledge of potential incoming gateways, but it is better to try knowledge of potential incoming gateways, but it is better to try
to provide some indication even if not successful; at the least, a to provide some indication even if not successful; at the least, a
human-readable indication that the article should not be gated human-readable indication that the article should not be gated
back to Netnews can help locate a human problem. back to Netnews can help locate a human problem.
4. Netnews control messages should not be gated to another medium 4. Netnews control messages should not be gated to another medium
unless they would somehow be meaningful in that medium. unless they would somehow be meaningful in that medium.
5. Changes MAY be made to the Content-Transfer-Encoding of some or
all parts of the body, and even to the charsets specified in
encoded-words or in Content-Type-headers, but such changes SHOULD
NOT be made unless absolutely necessary.
7.9.2. Duties of an Incoming Gateway 7.9.2. Duties of an Incoming Gateway
The incoming gateway has the serious responsibility of ensuring that The incoming gateway has the serious responsibility of ensuring that
all of the requirements of this standard are met by the articles that all of the requirements of this standard are met by the articles that
it forms. In addition to its special duties as a gateway, it bears it forms. In addition to its special duties as a gateway, it bears
all of the duties and responsibilities of an injecting agent as well, all of the duties and responsibilities of an injecting agent as well,
and additionally has the same responsibility of a relaying agent to and additionally has the same responsibility of a relaying agent to
reject articles that it has already gatewayed. reject articles that it has already gatewayed.
An incoming gateway MUST NOT gate the same message twice. It may not An incoming gateway MUST NOT gate the same message twice. It may not
be possible to ensure this in the face of mangling or modification of be possible to ensure this in the face of mangling or modification of
the message, but at the very least a gateway, when given a copy of a the message, but at the very least a gateway, when given a copy of a
message it has already gated identical except for trace headers (like message it has already gated identical except for trace headers (like
Received in Email or Path in Netnews) MUST NOT gate the message Received in Email or Path in Netnews) MUST NOT gate the message
again. An incoming gateway SHOULD take precautions against having again. An incoming gateway SHOULD take precautions against having
News Article Architecture and Protocols August 2004
this rule bypassed by modifications of the message that can be this rule bypassed by modifications of the message that can be
anticipated. anticipated.
News articles prepared by gateways MUST be legal news articles. In News articles prepared by gateways MUST be legal news articles. In
particular, they MUST include all of the mandatory headers, MUST particular, they MUST include all of the mandatory headers, MUST
fully conform to the restrictions on said headers, and SHOULD exclude fully conform to the restrictions on said headers, and SHOULD exclude
any deprecated headers (a-4.2.1). This often requires that a gateway any deprecated headers (a-4.2.1). This often requires that a gateway
function not only as a relaying agent, but also partly as a posting function not only as a relaying agent, but also partly as a posting
agent, aiding in the synthesis of a conforming article from non- agent, aiding in the synthesis of a conforming article from non-
conforming input. conforming input.
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Incoming gateways MUST NOT pass control messages (articles containing Incoming gateways MUST NOT pass control messages (articles containing
a Control- or Supersedes-header) without removing or renaming that a Control- or Supersedes-header) without removing or renaming that
header. Gateways MAY, however, generate their own cancel messages, header. Gateways MAY, however, generate their own cancel messages,
under the general allowance for injecting agents to cancel their own under the general allowance for injecting agents to cancel their own
messages ([USEAGE]). If a gateway receives a message that it can messages ([USEAGE]). If a gateway receives a message that it can
determine is a valid equivalent of a cancel message in the medium it determine is a valid equivalent of a cancel message in the medium it
is gatewaying, it SHOULD discard that message without gatewaying it, is gatewaying, it SHOULD discard that message without gatewaying it,
generate a corresponding cancel message of its own, and inject that generate a corresponding cancel message of its own, and inject that
cancel message. cancel message.
News Article Architecture and Protocols September 2004
Incoming gateways MUST NOT inject control messages other than Incoming gateways MUST NOT inject control messages other than
cancels. Encapsulation SHOULD be used instead of gatewaying, when cancels. Encapsulation SHOULD be used instead of gatewaying, when
direct posting is not possible or desirable. direct posting is not possible or desirable.
NOTE: It is not unheard of for mail-to-news gateways to be used NOTE: It is not unheard of for mail-to-news gateways to be used
to post control messages, but encapsulation should be used for to post control messages, but encapsulation should be used for
these cases instead. Gateways by their very nature are these cases instead. Gateways by their very nature are
particularly prone to loops. Spews of normal articles are bad particularly prone to loops. Spews of normal articles are bad
enough; spews of control messages with special significance to enough; spews of control messages with special significance to
the news system, possibly resulting in high processing load or the news system, possibly resulting in high processing load or
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NOTE: Message identifiers play a central role in the prevention NOTE: Message identifiers play a central role in the prevention
of duplicates, and their correct use by gateways will do much to of duplicates, and their correct use by gateways will do much to
prevent loops. Netnews does, however, require that message prevent loops. Netnews does, however, require that message
identifiers be unique, and therefore message identifiers from identifiers be unique, and therefore message identifiers from
other media may not be suitable for use without modification. A other media may not be suitable for use without modification. A
balance must be struck by the gateway between preserving balance must be struck by the gateway between preserving
information used to prevent loops and generating unique message information used to prevent loops and generating unique message
identifiers. identifiers.
News Article Architecture and Protocols August 2004
Exceptionally, if there are multiple incoming gateways for a Exceptionally, if there are multiple incoming gateways for a
particular set of messages, each to a different newsgroup(s), each particular set of messages, each to a different newsgroup(s), each
one SHOULD generate a message identifier unique to that gateway. Each one SHOULD generate a message identifier unique to that gateway. Each
incoming gateway nonetheless MUST ensure that it does not gate the incoming gateway nonetheless MUST ensure that it does not gate the
same message twice. same message twice.
NOTE: Consider the example of two gateways of a given mailing NOTE: Consider the example of two gateways of a given mailing
list into the world-wide Usenet newsgroups, both of which list into the world-wide Usenet newsgroups, both of which
preserve the email message identifier. Each newsgroup may then preserve the email message identifier. Each newsgroup may then
receive a portion of the messages (different sites seeing receive a portion of the messages (different sites seeing
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"official" gateway, some other method of generating message "official" gateway, some other method of generating message
identifiers has to be used to avoid collisions. It would identifiers has to be used to avoid collisions. It would
obviously be preferable for there to be only one gateway which obviously be preferable for there to be only one gateway which
crossposts, but this may not be possible to coordinate. crossposts, but this may not be possible to coordinate.
If no date information is available, the gateway MAY supply a Date- If no date information is available, the gateway MAY supply a Date-
header with the gateway's current date. If no injection-date header with the gateway's current date. If no injection-date
information is available, the gateway MUST supply an Injection-Date- information is available, the gateway MUST supply an Injection-Date-
header with whatever date information is available, and otherwise header with whatever date information is available, and otherwise
with the gateway's current date. If only partial information is with the gateway's current date. If only partial information is
News Article Architecture and Protocols September 2004
available (e.g. date but not time), this SHOULD be fleshed out to a available (e.g. date but not time), this SHOULD be fleshed out to a
full Date- and/or Injection-Date-header by adding default values full Date- and/or Injection-Date-header by adding default values
rather than discarding this information. Only in very exceptional rather than discarding this information. Only in very exceptional
circumstances should Date information be discarded, as it plays an circumstances should Date information be discarded, as it plays an
important role in preventing reinjection of old messages. important role in preventing reinjection of old messages.
An incoming gateway MUST add a Sender-header to the news article it An incoming gateway MUST add a Sender-header to the news article it
forms containing the mailbox of the administrator of the gateway. forms containing the mailbox of the administrator of the gateway.
Problems with the gateway may be reported to this mailbox. The Problems with the gateway may be reported to this mailbox. The
display-name portion of this mailbox SHOULD indicate that the entity display-name portion of this mailbox SHOULD indicate that the entity
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news article in the generated email message. The mail-to-news news article in the generated email message. The mail-to-news
gateway likewise preserves the email message identifier provided gateway likewise preserves the email message identifier provided
that it is syntactically valid for Netnews. This allows the news that it is syntactically valid for Netnews. This allows the news
system's built-in suppression of duplicates to serve as the first system's built-in suppression of duplicates to serve as the first
line of defense against loops. line of defense against loops.
2. The news-to-mail gateway adds an X-Gateway-header to all messages 2. The news-to-mail gateway adds an X-Gateway-header to all messages
it generates. The mail-to-news gateway discards any incoming it generates. The mail-to-news gateway discards any incoming
messages containing this header. This is robust against mailing messages containing this header. This is robust against mailing
list managers that replace the message identifier, and against any list managers that replace the message identifier, and against any
News Article Architecture and Protocols August 2004
number of email hops, provided that the other message headers are number of email hops, provided that the other message headers are
preserved. preserved.
3. The mail-to-news gateway inserts the host name from which it 3. The mail-to-news gateway inserts the host name from which it
received the email message in the pre-injection region of the Path received the email message in the pre-injection region of the Path
(a-5.6.3). The news-to-mail gateway refuses to gateway any (a-5.6.3). The news-to-mail gateway refuses to gateway any
message that contains the list server name in the pre-injection message that contains the list server name in the pre-injection
region of its Path-header. This is robust against any amount of region of its Path-header. This is robust against any amount of
munging of the message headers by the mailing list, provided that munging of the message headers by the mailing list, provided that
the email only goes through one hop. the email only goes through one hop.
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4. The mail-to-news gateway is designed never to generate bounces to 4. The mail-to-news gateway is designed never to generate bounces to
the envelope sender. Instead, articles that are rejected by the the envelope sender. Instead, articles that are rejected by the
news server (for reasons not warranting silent discarding of the news server (for reasons not warranting silent discarding of the
message) result in a bounce message sent to an errors address message) result in a bounce message sent to an errors address
known not to forward to any mailing lists, so that they can be known not to forward to any mailing lists, so that they can be
handled by the news administrators. handled by the news administrators.
These precautions have proven effective in practice at preventing These precautions have proven effective in practice at preventing
loops for this particular application (bidirectional gatewaying loops for this particular application (bidirectional gatewaying
between mailing lists and locally distributed newsgroups where both between mailing lists and locally distributed newsgroups where both
News Article Architecture and Protocols September 2004
gateways can be designed together). General gatewaying to world-wide gateways can be designed together). General gatewaying to world-wide
newsgroups poses additional difficulties; one must be very wary of newsgroups poses additional difficulties; one must be very wary of
strange configurations, such as a newsgroup gated to a mailing list strange configurations, such as a newsgroup gated to a mailing list
which is in turn gated to a different newsgroup. which is in turn gated to a different newsgroup.
8. Security and Related Considerations 8. Security and Related Considerations
There is no security. Don't fool yourself. Usenet is a prime example There is no security. Don't fool yourself. Usenet is a prime example
of an Internet Adhocratic-Anarchy; that is, an environment in which of an Internet Adhocratic-Anarchy; that is, an environment in which
trust forms the basis of all agreements. It works. trust forms the basis of all agreements. It works.
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The flooding algorithm is extremely good at finding any path by which The flooding algorithm is extremely good at finding any path by which
articles can leave a subnet with supposedly restrictive boundaries, articles can leave a subnet with supposedly restrictive boundaries,
and substantial administrative effort is required to avoid this. and substantial administrative effort is required to avoid this.
Organizations wishing to control such leakage are strongly advised to Organizations wishing to control such leakage are strongly advised to
designate a small number of official gateways to handle all news designate a small number of official gateways to handle all news
exchange with the outside world (however, making such gateways too exchange with the outside world (however, making such gateways too
restrictive can also encourage the setting up of unofficial paths restrictive can also encourage the setting up of unofficial paths
which can be exceedingly hard to track down). which can be exceedingly hard to track down).
News Article Architecture and Protocols August 2004
The sendme control message (6.4), insofar as it is still used, can be The sendme control message (6.4), insofar as it is still used, can be
used to request articles with a given message identifier, even one used to request articles with a given message identifier, even one
that is not supposed to be supplied to the requestor. that is not supposed to be supplied to the requestor.
8.2. Attacks 8.2. Attacks
8.2.1. Denial of Service 8.2.1. Denial of Service
The proper functioning of individual newsgroups can be disrupted by The proper functioning of individual newsgroups can be disrupted by
the massive posting of "noise" articles, by the repeated posting of the massive posting of "noise" articles, by the repeated posting of
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to their precursors, or which quote their precursors in full with the to their precursors, or which quote their precursors in full with the
addition of minimal extra material (especially if this process is addition of minimal extra material (especially if this process is
iterated), and by crossposting to, or setting followups to, totally iterated), and by crossposting to, or setting followups to, totally
unrelated newsgroups. unrelated newsgroups.
Many have argued that "spam", massively multiposted (and to a lesser Many have argued that "spam", massively multiposted (and to a lesser
extent massively crossposted) articles, usually for advertising extent massively crossposted) articles, usually for advertising
purposes, also constitutes a DoS attack in its own regard. This may purposes, also constitutes a DoS attack in its own regard. This may
be so. be so.
News Article Architecture and Protocols September 2004
Such articles intended to deny service, or other articles of an Such articles intended to deny service, or other articles of an
inflammatory nature, may also have their From or Reply-To addresses inflammatory nature, may also have their From or Reply-To addresses
set to valid but incorrect email addresses, thus causing large set to valid but incorrect email addresses, thus causing large
volumes of email to descend on the true owners of those addresses. volumes of email to descend on the true owners of those addresses.
Similar effects could be caused by any email header which could cause Similar effects could be caused by any email header which could cause
every reading agent receiving it to take some externally visible every reading agent receiving it to take some externally visible
action. For example, the Disposition-Notification-To-header defined action. For example, the Disposition-Notification-To-header defined
in [RFC 2298] could cause huge numbers of acknowledgements to be in [RFC 2298] could cause huge numbers of acknowledgements to be
emailed to an unsuspecting third party (for which reason [RFC 2298] emailed to an unsuspecting third party (for which reason [RFC 2298]
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5.6.1) and may thus prevent the true owner of a forged From or 5.6.1) and may thus prevent the true owner of a forged From or
Reply-To address from ever seeing it. Reply-To address from ever seeing it.
A malicious complainer may submit a modified copy of an article (e.g. A malicious complainer may submit a modified copy of an article (e.g.
with an altered Injection-Info-header) to the administrator of an with an altered Injection-Info-header) to the administrator of an
injecting agent in an attempt to discredit the author of that article injecting agent in an attempt to discredit the author of that article
and even to have his posting privileges removed. Administrators and even to have his posting privileges removed. Administrators
should therefore obtain a genuine copy of the article from their own should therefore obtain a genuine copy of the article from their own
serving agent before taking such precipitate action. serving agent before taking such precipitate action.
News Article Architecture and Protocols August 2004
Administrative agencies with responsibility for establishing policies Administrative agencies with responsibility for establishing policies
in particular hierarchies can and should set bounds upon the in particular hierarchies can and should set bounds upon the
behaviour that is considered acceptable within those hierarchies (for behaviour that is considered acceptable within those hierarchies (for
example by promulgating charters for individual newsgroups, and other example by promulgating charters for individual newsgroups, and other
codes of conduct). codes of conduct).
Whilst this standard places an onus upon injecting agents to bear Whilst this standard places an onus upon injecting agents to bear
responsibility for the misdemeanours of their posters (which includes responsibility for the misdemeanours of their posters (which includes
non-adherence to established policies of the relevant hierarchies as non-adherence to established policies of the relevant hierarchies as
provided in section 7.2), and to provide assistance to the rest of provided in section 7.2), and to provide assistance to the rest of
the network by making proper use of the Injection-Info- (a-6.19) and the network by making proper use of the Injection-Info- (a-6.19) and
Complaints-To- (a-6.20) headers, it makes no provision for Complaints-To- (a-6.20) headers, it makes no provision for
enforcement, which may in consequence be patchy. Nevertheless, enforcement, which may in consequence be patchy. Nevertheless,
injecting sites which persistently fail to honour their injecting sites which persistently fail to honour their
responsibilities or to comply with generally accepted standards of responsibilities or to comply with generally accepted standards of
behaviour are likely to find themselves blacklisted, with their behaviour are likely to find themselves blacklisted, with their
articles refused propagation and even subject to cancellation, and articles refused propagation and even subject to cancellation, and
other relaying sites would be well advised to withdraw peering other relaying sites would be well advised to withdraw peering
arrangements from them. arrangements from them.
News Article Architecture and Protocols September 2004
8.2.2. Compromise of System Integrity 8.2.2. Compromise of System Integrity
The posting of unauthorized (as determined by the policies of the The posting of unauthorized (as determined by the policies of the
relevant hierarchy) control messages can cause unwanted newsgroups to relevant hierarchy) control messages can cause unwanted newsgroups to
be created, or wanted ones removed, from serving agents. be created, or wanted ones removed, from serving agents.
Administrators of such agents SHOULD therefore take steps to verify Administrators of such agents SHOULD therefore take steps to verify
the authenticity of such control messages, either by manual the authenticity of such control messages, either by manual
inspection (particularly of the Approved-header) or by checking any inspection (particularly of the Approved-header) or by checking any
digital signatures that may be provided (see a-7.1). In addition, digital signatures that may be provided (see a-7.1). In addition,
they SHOULD periodically compare the newsgroups carried against any they SHOULD periodically compare the newsgroups carried against any
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all cancel messages on account of the difficulty of conducting such all cancel messages on account of the difficulty of conducting such
checks. checks.
Improperly configured serving agents can allow articles posted to Improperly configured serving agents can allow articles posted to
moderated groups onto the net without first being approved by the moderated groups onto the net without first being approved by the
moderator. Injecting agents SHOULD verify that moderated articles moderator. Injecting agents SHOULD verify that moderated articles
were received from one of the entities given in their Approved- were received from one of the entities given in their Approved-
headers and/or check any digital signatures that may be provided (see headers and/or check any digital signatures that may be provided (see
a-7.1). a-7.1).
News Article Architecture and Protocols August 2004
The filename parameter of the Archive-header (a-6.12) can be used to The filename parameter of the Archive-header (a-6.12) can be used to
attempt to store archived articles in inappropriate locations. attempt to store archived articles in inappropriate locations.
Archiving sites should be suspicious of absolute filename parameters, Archiving sites should be suspicious of absolute filename parameters,
as opposed to those relative to some location of the archiver's as opposed to those relative to some location of the archiver's
choosing. choosing.
There may be weaknesses in particular implementations that are There may be weaknesses in particular implementations that are
subject to malicious exploitation. In particular, it has not been subject to malicious exploitation. In particular, it has not been
unknown for complete shell scripts to be included within Control- unknown for complete shell scripts to be included within Control-
headers. Implementors need to be aware of this. headers. Implementors need to be aware of this.
Reading agents should be chary of acting automatically upon MIME Reading agents should be chary of acting automatically upon MIME
objects with an "application" Content-Type that could change the objects with an "application" Content-Type that could change the
state of that agent, except in contexts where such applications are state of that agent, except in contexts where such applications are
specifically expected (see a-6.21). Even the Content-Type specifically expected (see a-6.21). Even the Content-Type
"text/html" could have unexpected side effects on account of embedded "text/html" could have unexpected side effects on account of embedded
objects, especially embedded executable code or URLs that invoke objects, especially embedded executable code or URLs that invoke
non-news protocols such as HTTP [RFC 2616]. It is therefore non-news protocols such as HTTP [RFC 2616]. It is therefore
generally recommended that reading agents do not enable the execution generally recommended that reading agents do not enable the execution
of such code (since it is extremely unlikely to have a valid of such code (since it is extremely unlikely to have a valid
News Article Architecture and Protocols September 2004
application within Netnews) and that they only honour URLs referring application within Netnews) and that they only honour URLs referring
to other parts of the same article. to other parts of the same article.
Non-printable characters embedded in article bodies may have Non-printable characters embedded in article bodies may have
surprising effects on printers or terminals, notably by reconfiguring surprising effects on printers or terminals, notably by reconfiguring
them in undesirable ways which may become apparent only after the them in undesirable ways which may become apparent only after the
reading agent has terminated. reading agent has terminated.
8.3. Liability 8.3. Liability
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Users who are concerned about such matters should seek advice from Users who are concerned about such matters should seek advice from
competent legal authorities. competent legal authorities.
9. IANA Considerations 9. IANA Considerations
IANA is requested to register the following media types, described IANA is requested to register the following media types, described
elsewhere in this standard, for use with the Content-Type-header, in elsewhere in this standard, for use with the Content-Type-header, in
the IETF tree in accordance with the procedures set out in [RFC the IETF tree in accordance with the procedures set out in [RFC
2048]. 2048].
News Article Architecture and Protocols August 2004
application/news-transmission (5.1) application/news-transmission (5.1)
application/news-groupinfo (5.3) application/news-groupinfo (5.3)
application/news-checkgroups (5.4) application/news-checkgroups (5.4)
IANA is also requested to change the status of the following media IANA is also requested to change the status of the following media
type to "OBSOLETE". type to "OBSOLETE".
message/news (5.2) message/news (5.2)
NOTE: "Application/news-transmission" is an update, with NOTE: "Application/news-transmission" is an update, with
clarification and additional optional parameters, to an existing clarification and additional optional parameters, to an existing
registration. "Message/rfc822" should now be used in place of registration. "Message/rfc822" should now be used in place of
the obsoleted "message/news". the obsoleted "message/news".
10. References 10. References
[To Do: Split this section into Normative and Informative references. [To Do: Split this section into Normative and Informative references.
This will probably be delayed until the final draft, for technical This will probably be delayed until the final draft, for technical
reasons.] reasons.]
News Article Architecture and Protocols September 2004
[ANSI X3.4] "American National Standard for Information Systems - [ANSI X3.4] "American National Standard for Information Systems -
Coded Character Sets - 7-Bit American National Standard Code for Coded Character Sets - 7-Bit American National Standard Code for
Information Interchange (7-Bit ASCII)", ANSI X3.4, 1986. Information Interchange (7-Bit ASCII)", ANSI X3.4, 1986.
[ARTICLE] Charles H. Lindsey, "News Article Format and Transmission", [ARTICLE] Charles H. Lindsey, "News Article Format and Transmission",
draft-ietf-usefor-article-format-*.txt. draft-ietf-usefor-article-format-*.txt.
[NNTP] Clive D.W. Feather, "Network News Transport Protocol", draft- [NNTP] Clive D.W. Feather, "Network News Transport Protocol", draft-
ietf-nntpext-base-*.txt. ietf-nntpext-base-*.txt.
skipping to change at page 44, line 5 skipping to change at page 46, line 41
[RFC 2298] R. Fajman, "An Extensible Message Format for Message [RFC 2298] R. Fajman, "An Extensible Message Format for Message
Disposition Notifications", RFC 2298, March 1998. Disposition Notifications", RFC 2298, March 1998.
[RFC 2606] D. Eastlake and A. Panitz, "Reserved Top Level DNS Names", [RFC 2606] D. Eastlake and A. Panitz, "Reserved Top Level DNS Names",
RFC 2606, June 1999. RFC 2606, June 1999.
[RFC 2616] R. Fielding, J. Gettys, J. Mogul, H. Frystyk, L. Masinter, [RFC 2616] R. Fielding, J. Gettys, J. Mogul, H. Frystyk, L. Masinter,
P. Leach, and T. Berners-Lee, "Hypertext Transfer Protocol -- P. Leach, and T. Berners-Lee, "Hypertext Transfer Protocol --
HTTP/1.1", RFC 2616, June 1999. HTTP/1.1", RFC 2616, June 1999.
News Article Architecture and Protocols August 2004
[RFC 2822] P. Resnick, "Internet Message Format", RFC 2822, April [RFC 2822] P. Resnick, "Internet Message Format", RFC 2822, April
2001. 2001.
[RFC 3864] G. Klyne, M. Nottingham, and J. Mogul, "Registration
procedures for message header fields", RFC 3864.
[RFC 850] Mark R. Horton, "Standard for interchange of Usenet [RFC 850] Mark R. Horton, "Standard for interchange of Usenet
messages", RFC 850, June 1983. messages", RFC 850, June 1983.
[RFC 976] Mark R. Horton, "UUCP mail interchange format standard", [RFC 976] Mark R. Horton, "UUCP mail interchange format standard",
RFC 976, February 1986. RFC 976, February 1986.
[Son-of-1036] Henry Spencer, "News article format and transmission", [Son-of-1036] Henry Spencer, "News article format and transmission",
<ftp://ftp.zoo.toronto.edu/pub/news.txt.Z>, June 1994. <ftp://ftp.zoo.toronto.edu/pub/news.txt.Z>, June 1994.
[USEAGE] draft-ietf-usefor-useage-*.txt. [USEAGE] draft-ietf-usefor-useage-*.txt.
[USEFOR] C. H. Lindsey et al, "News Article Format", draft-ietf- [USEFOR] C. H. Lindsey et al, "News Article Format", draft-ietf-
usefor-usefor-format-*.txt. usefor-usefor-format-*.txt.
News Article Architecture and Protocols September 2004
[USEPRO] This Standard. [USEPRO] This Standard.
11. Acknowledgements 11. Acknowledgements
TBD TBD
12. Contact Address 12. Contact Address
Editor Editor
skipping to change at page 44, line 53 skipping to change at page 47, line 36
[ [
Working group chair Working group chair
Alexey Melnikov <alexey.melnikov-usefor@isode.com> Alexey Melnikov <alexey.melnikov-usefor@isode.com>
] ]
Comments on this draft should preferably be sent to the mailing list Comments on this draft should preferably be sent to the mailing list
of the Usenet Format Working Group at of the Usenet Format Working Group at
usenet-format@landfield.com
shortly to be replaced by
ietf-usefor@imc.org. ietf-usefor@imc.org.
News Article Architecture and Protocols August 2004
Appendix A.1 - A-News Article Format Appendix A.1 - A-News Article Format
The obsolete "A News" article format consisted of exactly five lines The obsolete "A News" article format consisted of exactly five lines
of header information, followed by the body. For example: of header information, followed by the body. For example:
Aeagle.642 Aeagle.642
news.misc news.misc
cbosgd!mhuxj!mhuxt!eagle!jerry cbosgd!mhuxj!mhuxt!eagle!jerry
Fri Nov 19 16:14:55 1982 Fri Nov 19 16:14:55 1982
Usenet Etiquette - Please Read Usenet Etiquette - Please Read
skipping to change at page 45, line 28 skipping to change at page 48, line 5
body body
body body
The first line consisted of an "A" followed by an article ID The first line consisted of an "A" followed by an article ID
(analogous to a message identifier and used for similar purposes). (analogous to a message identifier and used for similar purposes).
The second line was the list of newsgroups. The third line was the The second line was the list of newsgroups. The third line was the
path. The fourth was the date, in the format above (all fields fixed path. The fourth was the date, in the format above (all fields fixed
width), resembling an Internet date but not quite the same. The fifth width), resembling an Internet date but not quite the same. The fifth
was the subject. was the subject.
News Article Architecture and Protocols September 2004
This format is documented for archeological purposes only. Articles This format is documented for archeological purposes only. Articles
MUST NOT be generated in this format. MUST NOT be generated in this format.
Appendix A.2 - Early B-News Article Format Appendix A.2 - Early B-News Article Format
The obsolete pseudo-Internet article format, used briefly during the The obsolete pseudo-Internet article format, used briefly during the
transition between the A News format and the modern format, followed transition between the A News format and the modern format, followed
the general outline of a MAIL message but with some non-standard the general outline of a MAIL message but with some non-standard
headers. For example: headers. For example:
skipping to change at page 46, line 5 skipping to change at page 48, line 41
header. The Title-header contained what is now the Subject-content. header. The Title-header contained what is now the Subject-content.
The Posted-header contained what is now the Date-content. The The Posted-header contained what is now the Date-content. The
Article-I.D.-header contained an article ID, analogous to a message Article-I.D.-header contained an article ID, analogous to a message
identifier and used for similar purposes. The Newsgroups- and identifier and used for similar purposes. The Newsgroups- and
Expires-headers were approximately as now. The Received-header Expires-headers were approximately as now. The Received-header
contained the date when the latest relaying agent to process the contained the date when the latest relaying agent to process the
article first saw it. All dates were in the above format, with all article first saw it. All dates were in the above format, with all
fields fixed width, resembling an Internet date but not quite the fields fixed width, resembling an Internet date but not quite the
same. same.
News Article Architecture and Protocols August 2004
This format is documented for archeological purposes only. Articles This format is documented for archeological purposes only. Articles
MUST NOT be generated in this format. MUST NOT be generated in this format.
Appendix A.3 - Obsolete Control Messages Appendix A.3 - Obsolete Control Messages
This present standard obsoletes certain control messages defined in This present standard obsoletes certain control messages defined in
[RFC 1036] (see 6.5), all of which had the effect of requesting a [RFC 1036] (see 6.5), all of which had the effect of requesting a
description of a relaying or serving agent's software, or its peering description of a relaying or serving agent's software, or its peering
arrangements with neighbouring sites, to be emailed to the article's arrangements with neighbouring sites, to be emailed to the article's
reply address. Whilst of some utility when Usenet was much smaller reply address. Whilst of some utility when Usenet was much smaller
than it is now, they had become no more than a tool for the malicious than it is now, they had become no more than a tool for the malicious
sending of mailbombs. Moreover, many organizations now consider sending of mailbombs. Moreover, many organizations now consider
information about their internal connectivity to be confidential. information about their internal connectivity to be confidential.
version version
sendsys sendsys
whogets whogets
senduuname senduuname
News Article Architecture and Protocols September 2004
"Version" requested details of the transport software in use at a "Version" requested details of the transport software in use at a
site. "Sendsys" requested the full list of newsgroups taken, and the site. "Sendsys" requested the full list of newsgroups taken, and the
peering arrangements. "Who gets" was similar, but restricted to a peering arrangements. "Who gets" was similar, but restricted to a
named newsgroup. "Senduuname" resembled "sendsys" but restricted to named newsgroup. "Senduuname" resembled "sendsys" but restricted to
the list of peers connected by UUCP. the list of peers connected by UUCP.
Historically, a checkgroups body consisting of one or two lines, the Historically, a checkgroups body consisting of one or two lines, the
first of the form "-n newsgroup", caused check-groups to apply to first of the form "-n newsgroup", caused check-groups to apply to
only that single newsgroup. only that single newsgroup.
skipping to change at page 47, line 5 skipping to change at page 49, line 43
might or might not be available; neither does it represent that it might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and IETF's procedures with respect to rights in standards-track and
standards-related documentation can be found in BCP-11. Copies of standards-related documentation can be found in BCP-11. Copies of
claims of rights made available for publication and any assurances of claims of rights made available for publication and any assurances of
licenses to be made available, or the result of an attempt made to licenses to be made available, or the result of an attempt made to
obtain a general license or permission for the use of such obtain a general license or permission for the use of such
proprietary rights by implementors or users of this specification can proprietary rights by implementors or users of this specification can
be obtained from the IETF Secretariat. be obtained from the IETF Secretariat.
News Article Architecture and Protocols August 2004
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive this standard. Please address the information to the IETF Executive
Director. Director.
Full Copyright Statement Full Copyright Statement
Copyright (C) The Internet Society (2003). All Rights Reserved Copyright (C) The Internet Society (2003). All Rights Reserved
This document and translations of it may be copied and furnished to This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other the copyright notice or references to the Internet Society or other
News Article Architecture and Protocols September 2004
Internet organizations, except as needed for the purpose of Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than followed, or as required to translate it into languages other than
English. English.
The limited permissions granted above are perpetual and will not be The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns. revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Appendix C - Change Log Appendix C - Change Log
[This Appendix is to be removed prior to final publication.] [This Appendix is to be removed prior to final publication.]
For version 01
1 Numerous texts describing protocol features related to
particular headers in parts of [ARTICLE] which were destined to
become part of [USEFOR] have been moved to appropriate locations
within section 7 of this document. Such revised texts will be
found in sections
7.2.2 Steps 4, 6, 7, 10, 11, 12;
7.2.3 Step 1(b);
7.3 introductory paragraphs, Steps 1, 4, 8, 9, and some final
paragraphs;
7.4 introductory and final paragraphs;
7.9.1 Step 5.
2 A section on "Duties of a Reading Agent" (7.8) has been added.
3 Some demotions MUST -> SHOULD -> MAY, as noted in pseudo-
comments, have been made or proposed in sections
7.3
7.3 Step 4.
4 Part of the procedure for examining Path-headers by relaying
agents has been moved to serving agents, as explained in
pseudo-comments in section 7.4.
5 Some renumbering of sections and minor textual clarifications.
 End of changes. 

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