NNTP - Protocols, formats, standards ...
NNTP
NNTP is short for Network News Transfer Protocol. It is an Internet
protocol for client-server transfer of USENET news messages. The protocol
is formally specified in RFC
977. When in doubt about the correct implementation of the NNTP protocol
you should read the RFC.
XOVER
The formal standard for USENET news transfer over the Internet is the
NNTP protocol. Most news servers and news readers on the Internet support
it.
Unfortunately, the NNTP protocol does not specify any commands which
can be used for efficient access to the news server over a slow connection.
A number of extensions to the NNTP protocol have been devised for this
purpose.
Skim currently uses the XOVER NNTP extension for relatively efficient
access to the News OverView (NOV) database. Many, but not all, news servers
support it. The XOVER command is documented in an Internet draft.
Note that an NNTP server is not required to support the XOVER extension.
With a single XOVER command skim can get the relevant header lines
of all new articles in a particular newsgroup. To get the same information
with commands specified by NNTP proper, skim would have to fetch
the complete headers of all new articles one by one.
To make matters worse, some news servers do support the XOVER extension,
but not the associated list overview.fmt command. Skim is not currently
equipped to talk to news servers without support for overview.fmt. Sorry
about that.
This item is on the wish list.
Skim is of no use to you when your news server does not support the
XOVER extension. Sorry about that. Support for pure NNTP servers
and for servers with the XHDR extension is on the wish list.
The format of USENET articles
The formal standard for the format of USENET articles is RFC 1036.
Skim will take care of most of the technical requirements in RFC
1036 when it constructs a new article or a reply. For
example, skim will construct a technically correct 'References: ' header
line and a 'Subject:' header line for the reply to a USENET article.
Pseudo threading
When skim presents a list of article subjects it arranges the
subjects by means of pseudo threading.
This means that skim sorts the header lines by subject (ignoring the
'Re:' prefix) to bring related subjects together.
For example:
Bill Gates 12 How can
your software be free?
Linux Torvalds 68 Re: How can your software
be free?
Matt Welsh 75 Re:
Howto print a man page?
Bill Gates 17 $$$!
(Was: How can your software be free?)
Skim does not currently support real threading based on the 'References:'
header line. This means that you cannot see the hierarchical structure
of a thread and you cannot recognize a thread in which the subject changes.
Also some subjects may appear to be related, even though they are in different
threads.
Real 'Reference' based threading is an item on the wish list.
Rules and guidelines for writing articles
Skim does not currently provide a special user interface for editing
new articles and replies. You must use a normal text editor to edit the
body of the article and the header lines.
To prevent you from posting an invalid article, skim overwrites most
of the headerlines when it posts an article. You should only edit the following
header lines:
Subject
Newsgroups
Followup-to
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