                            OVERVIEW

Leafnode is a USENET software package designed for small sites, with a
few tens of readers and only a slow link to the net.

It consists of three programs:

 - Leafnode is the NNTP server.  It talks to the normal news clients,
   and stores readership data.

 - Fetch is the NNTP news-gatherer.  It looks at the readership data
   Leafnode stores, and selects what groups to pull news from.

 - Texpire is responsible for deleting old and uninteresting news.  It
   deletes all discussion threads that are old and not recently read.

Only groups that someone has been reading in the past week are fetched
from the upstream NNTP server.  When someone stops reading a group,
fetch will stop reading that group a week later, and when someone
starts reading a group, fetch will grab all the articles it can in
that group the next time it runs.

Here are Leafnode's distinguishing features:

 - Uses very little disk space and bandwidth compared to other servers.
   Obviously truer for 3-user sites than for 30-user, and probably wholly
   untrue for 300-user sites.

 - Easy configuration and maintenance.  Leafnode tries very hard to
   recover automatically from error situations.

This list of Leafnode's weaknesses has been moved here from DONTREADME
due to popular demand:

 - Loses news.  In just about any error situation, leafnode tries to
   fix its problems by deleting the offending article.

 - Scales very badly.


                      FILES AND DIRECTORIES

Leafnode puts its files in three separate directories: The spool
directory, the library directory, and the binaries directory.

The spool directory is where news is stored, and nothing else.  This
defaults to /var/spool/news and can be changed in the config file.
There are some special directories here; see the leafnode(8) man page.

The library directory contains the configurarion file, the newsgroup
information file, and any more long-lived supporting files that may
be added in the future.

The binaries directory, /usr/local/sbin by default, contains the three
executable programs, texpire, fetch and leafnode.


Arnt Gulbrandsen <agulbra@troll.no>
