leafnode(8)

NAME
leafnode - NNTP server for small (dialup) sites

SYNOPSIS
leafnode

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.

The leafnode program itself is the NNTP server. It is run from /etc/inetd.conf when someone wants to read news. The other parts of the package, fetchnews and texpire, are responsible for fetching new news from another server, and for deleting old news.

ACCESS CONTROL
No authentication or access control is supported. This is a deliberate omission: Implementing this is a job which should not be redone for each and every service.

I recommend that either firewalling or tcpd be used for access control.

FILES
All these files and directories must be writable by user "news".

/etc/leafnode/config contains the configuration parameters for leafnode. See CONFIGURATION below.

/var/spool/news contains the news articles; e.g. /var/spool/news/alt/fan/agulbra contains the articles in the alt.fan.agulbra group. Each directory contains articles in numbered files (decimal numbers, monotonically increasing), and a special file called .overview which contains the "Subject", "From", "Date", "Message-ID", "References", "Bytes" and "Lines" headers for each article in the group.

Several subdirectories are special:

/var/spool/news/leaf.node contains the files that leafnode creates during operation, for example the groupinfo file which contains information about each USENET newsgroup. This file is built by fetchnews (8). You can force a complete rebuild of the groupinfo file by calling fetchnews with the parameter -f (see fetchnews (8)).

/var/spool/news/out.going contains local postings that fetchnews(8) is to pass to the upstream NNTP server.

/var/spool/news/failed.postings contains local postings that the upstream server rejected. fetchnews(8) will create files in this directory, but none of the leafnode programs will delete anything in it.

/var/spool/news/message.id contains hard links to each message; this is used in place of the dbz database typically used by bigger servers. (A directory such as this is probably more efficient for the small servers leafnode is designed for but scales very badly.)

/var/spool/news/interesting.groups contains one file for each group an NNTP client has asked to read. leafnode will touch the the relevant file when a LISTGROUP, XOVER, XHDR, STAT, HEAD, BODY or ARTICLE command is issued immediately after a GROUP command is issued, and fetchnews(8) will retrieve all new articles in all groups whose files have been either

    - touched during the past two days, or

    - touched more than once, and at least once within the past week.

/etc/inetd.conf contains the line which starts leafnode. It is strongly recommended to start leafnode as user news.

CONFIGURATION
All configuration is done using the file /etc/leafnode/config. There is no GUI configuration tool yet.

The file has a rather standard Unix format: one line per argument, comments are introduced by a hash mark (#) and last until the end of the line. Below are examples on how the various parameters are specified.

MANDATORY PARAMETERS

server = news02.bigprovider.com
    "server" is used by fetchnews (8) to select what NNTP server(s) to retrieve news from and to post your articles to. You can specify more than one news server; in that case, the servers will be queried from the top down. If you want to post articles, at least one of your servers should allow you to post. In the example above, news02.bigprovider.com is the news server.

expire = 5
    "expire" is the number of days a thread should be kept around. In the example, five days after the thread has last been read, it is deleted by texpire (8).

SERVER-SPECIFIC OPTIONAL PARAMETERS

username = myname
    If any of your news servers requires authentification, you can enter your username on that server here. This field may occur multiple times, once after each server definition.

password = mypassword
    If any of your news servers requires authentification, you can enter your password on that server here. This field may occur multiple times, once after each server definition. Since the password is available in clear text, it is recommended that you set the rights on the config file as restrictive as possible, otherwise other users of your computer will be able to get your password(s) from that file.

timeout = 30
    By default, leafnode tries to connect for 10 seconds to a server and then gives up. If you have a slow server, you can try for a longer time by setting the timeout higher (in this example, 30 seconds). The timeout can be tuned individually for each server.

nodesc = 1
    Some servers do not deliver news groups descriptions correctly because they cannot parse the LIST NEWSGROUPS command. In that case, put this line after the "server" line.

port = 8000
    By default, leafnode tries to connect to its upstream news servers on the NNTP port (119). If your servers run on a different port, you can specify those here. This field may occur multiple times, once after each server definition.

GENERAL OPTIONAL PARAMETERS

hostname = host.domain.country
    If your messages do not already have message IDs (generated by the newsreader), Leafnode will generate a message ID for them. However, it will never ever overwrite an existing message ID. By default, it tries to do this from the name of your computer. However, some upstream servers demand message IDs of a certain type. In this case, you can override the name of your computer by setting "hostname" to a sensible value. The use of "hostname" to create fancy message IDs is possible, but strongly discouraged.

create_all_links = 1
    Normally, fetchnews will store articles only in the newsgroups which you consider interesting. If you set "create_all_links", fetchnews will create hardlinks for all newsgroups which it can find in the Newsgroups: header. This may be of interest if you want to apply a score- or killfile to the Xref: line.

maxfetch = 1000
    "maxfetch" specifies the maximum number of articles fetchnews (8) should fetch from the upstream server in each group. Its use is not advised, because if you use it you will not see all the traffic in a group. By default there is no limit.

initialfetch = 1
    "initialfetch" defines how many articles from a newly subscribed group should be fetched. The default is to fetch all old articles, which can get quite time-consuming when subscribing to a very busy group. This is equivalent to setting initialfetch to zero. If you want to get no old articles when subscribing to a new group, you should set initialfetch to one, as in the example above.

groupexpire very.crowded.group = 1

groupexpire very.crowded.hierarchy.* = 1
    "groupexpire" makes it possible to adjust expiry times for individual groups. Expiry times are given in days. This value is used by texpire (8). You can specify as many groupexpire lines as you like. It is possible to specify glob (7)-like wildcard expressions.

maxage = 10
    If an article turns up on your upstream news server which is older than "maxage" days it will not been fetched even if you don't have it yet. This is useful if your upstream server gets occasional "hiccups". The default is set to 10. If you want to switch this feature off, set maxage to some very large value, such as 100000 (this is equivalent to roughly 270 years).

maxlines = 2000
    If you want to avoid receiving very large articles, you may set the "maxlines" parameter to the maximal number of lines an article should have. By default, this feature is switched off.

minlines = 2
    Sometimes newsgroups are spammed with empty postings. To reject these postings, you can set the "minlines" parameter. Setting minlines to a value larger 4 is probably not a good idea since you will also start to kill "real" postings then. By default, this feature is switched off.

maxbytes = 100000
    If you want to avoid receiving very large articles, instead of using the "maxlines" parameter you can also use the "maxbytes" parameter. By default, this feature is switched off.

maxcrosspost = 5
    If you want to combat spam, you can filter out all postings that are posted to more than a certain number of newsgroups. The number is defined by setting "maxcrosspost". Setting this parameter to very low values is probably a bad idea. This feature is switched off by default.

filterfile = /etc/leafnode/filters
    Leafnode can filter the input headers for arbitrary regular expressions. These are stored in a file designated "filterfile". The format of "filterfile" is very simple, one regular expression per line. If one of the regular expressions fits to a header to be downloaded, the body of that article will be rejected. This feature is switched off by default. The format of the regular expressions is described in pcre (7).

timeout_short = 2
    By default, a group that has been accidentally touched is being fetched for two days. You can change this time by changing timeout_short.

timeout_long = 7
    By default, a group that has not been read at all is being fetched for seven days before being unsubscribed. This interval can be changed by setting timeout_long to a different value.

timeout_active = 90
    By default, active files from the upstream servers are re-read every 90 days. This interval can be changed by setting timeout_active to a different value. Be aware that reading an active file transfers about one MB of information if the server that you are using carries a reasonable number of groups (i.e. around 20000).

delaybody = 1
    With this option set, fetchnews (8) fetches only the headers of an article for visual inspection. Only when the headers have been read, the bodies of the articles will be retrieved the next time fetchnews (8) is called. This can save a huge amount of download time and disk space.

debugmode = 1
    With this option set, fetchnews (8), texpire (8) and leafnode (8) will start to log lots of debugging output via syslog (8) to news.debug. Use it for tracking down problems with your feed.

PROTOCOL
Here are the NNTP commands supported by this server.

ARTICLE
    Return the headers and body text of an article. Leafnode supports this imperfectly; the message-id and article number of the article may not be reported in the reply line. This does not affect any tested NNTP clients.

BODY
    Return the body text of an article. See ARTICLE.

GROUP
    Sets the current USENET group and article pointer, and returns the status information about this group.

HEAD
    Return the headers of an article. See ARTICLE.

HELP
    Accepted but I'm afraid it is not very helpful.

IHAVE
    Known but rejected.

LAST
    Moves the article pointer back by 1.

LIST
    Lists the available USENET groups.

LIST OVERVIEW.FMT
    List some extensions.

LISTGROUP
    Lists the articles present in the current group, or the argument group if an argument is present.

MODE
    Accepted and blithely ignored.

NEWGROUPS
    Lists newsgroups which have been newly created.

NEWNEWS
    Accepted but the reply is always empty. This command does not make sense for this server.

NEXT
    Moves the article pointer forward by 1.

POST
    Post a new article. Only scant syntax checking is performed. The article is sent to the upstream NNTP server by fetchnews(8).

QUIT
    Quit reading news.

SLAVE
    Accepted but ignored.

STAT
    Return the availability of an article. See ARTICLE.

XHDR
    Accepted, but supported only for the "Subject", "From", "Date", "Message-ID", "References", "Bytes" and "Lines" headers.

XOVER
    Returns the "Subject", "From", "Date", "Message-ID", "References", "Bytes" and "Lines" headers for the indicated article(s).

The rest of the commands given in the NNTP RFC or added in other servers are left out in order to keep the server simple and bug-free.

BUGS
None known.

AUTHOR
Written by Arnt Gulbrandsen <agulbra@troll.no> and copyright 1995 Troll Tech AS, Postboks 6133 Etterstad, 0602 Oslo, Norway, fax +47 22646949.

Modified by Cornelius Krasel <krasel@wpxx02.toxi.uni-wuerzburg.de>, Randolf Skerka <Randolf.Skerka@gmx.de> and Markus Enzenberger <enz@cip.physik.uni-muenchen.de>. Copyright of the modifications 1997-1999.

The initial development of leafnode has been paid for by Uninett AS (http://www.uninett.no/).

SEE ALSO
tcpd(8), hosts.allow(5), fetchnews(8), texpire(8), checkgroups(8), glob(7), pcre(7), RFC 977