fetch(8)

NAME

fetch - fetch news via NNTP

SYNOPSIS

fetch [-v] [-x number] [-l] [-n] [-f]

DESCRIPTION

Leafnode is a USENET package intended for small sites, where there are few users and little disk space, but where a large number of groups is desired.

The design of leafnode is intended to self-repair after problems, and to require no manual maintenance.

Fetch is the program which submits and retrieves new articles to or from the upstream NNTP server.

OPTIONS

-v: Be verbose. A maximum of four -v can be used (the more v, the more verbose):

-v: Warn about non-critical errors.

-vv: Be verbose whenever a group command occurs.

-vvv: Be verbose whenever an article command occurs.

-vvvv: For debugging purposes. Don't expect the additional output to make sense.

-x number: Go number articles back and try to re-fetch what's missing. Chiefly used for debugging purposes.

-l: Don't use supplementary servers ( -l is supposed to mean "local"). This does speed up the operation quite a bit.

-n: Don't unlink files in the interesting.groups directory. This avoids automatic unsubscription of newsgroups.

-f: Force rereading of whole active file from all upstream servers. This is usually occurring only very infrequently because it takes a long time.

FILES AND CONFIGURATION

See leafnode(8) for the list of files affected, and for information on configuring fetch.

ALGORITHM

Here is a brief description of what fetch does.

First, after connecting to the upstream NNTP server, all articles in /var/spool/news/out.going are posted using POST. If a posting fails, that article is moved to /var/spool/news/failed.postings which an administrator has to clean up once in a while. Moving a file back to /var/spool/news/out.going is sufficient to resubmit it.

Second, the upstream server's list of newsgroups (obtained using LIST ACTIVE and LIST NEWSGROUPS) is merged into leafnode's (this step is most often optimized away).

Third, fetch iterates over the list of newsgroups, performing a GROUP, an XHDR Message-ID and a number of HEAD and BODY commands for each group which has been read recently.

NOTES

Fetch does not use NEWNEWS or XOVER. NEWNEWS is not used because it is often very expensive, XOVER is not used because the information it obtains is also present in the article headers.

After some experiments, I decided that it was better to fetch all the articles in a group than to optimize away some; users would complain too loudly when the optmizer guessed wrongly. Leafnode is not intended to be all things to all men, and I have sacrificed the ability to read news from two upstream servers. (There is some support for it, but it is incomplete and undocumented at the time of writing.)

Fetch happens to support local groups, even though the rest of leafnode doesn't.

The only way to control what newsgroups are accessible to local users is to control what the upstream server lets fetch read, and that will not keep out all crossposts (endemic in e.g. the alt.sex groups). If your site is big enough that you need to control newsgroup access, consider using a news server which is designed for a big site.

Fetch sets its real and effective uid to "news", because almost all of the problems I have had with leafnode are due to files which aren't writable for user news.

BUGS

Fetch ignores the "Supersedes" and "Also-Cancel" headers. This needs to be fixed, or news.answers will suffer.

Never deletes a group from the list of active newgroups.

AUTHOR AND LICENCE

Modified by Cornelius Krasel <[email protected]>, Markus Enzenberger <[email protected]> and Randolf Skerka <[email protected]>. Copyright of the modifications 1997, 1998.

Use, modification and distribution is allowed without limitation, warranty, or liability of any kind.