.TH NNTPD 8C "5 March 1986"
.UC 4
.SH NAME
nntpd \- Network News Transfer Protocol server
.SH SYNOPSIS
.B /etc/nntpd
.br
.I (with /etc/inetd, see below)
.SH DESCRIPTION
.I Nntpd
is a TCP based server which supports the proposed standard
for the stream based transmission of network
news articles.
It can be used both by ``end user'' clients, and by
``system'' clients which transport news between machines.
.I Nntpd
operates at the port indicated in the ``nntp'' service
entry in
.I /etc/services.
The port number assigned by the Network Information Center
for this service is 119.
.PP
.I Nntpd
can operate either as a stand-alone server, or as a
server under
.IR inetd (1).
For stand-alone use,
.I nntpd
must be compiled with the -DALONE option, and is
invoked as mentioned in the synopsis above.
Under
.IR inetd (1),
the appropriate entry must be made in
.I /etc/inetd.conf,
and the server must be compiled without the
-ALONE flag.
.PP
The server handles clients on a one to one basis,
forking to take care of clients as they request
connections.  Each server changes its current
directory to the news spool directory (usually
.I /usr/spool/news)
and then executes commands from its client.
These commands are described in ARPA Internet
RFC 977, ``Network News Transfer Protocol;
A Proposed Standard for the Stream Based Transmission
of News Articles.''
.PP
Since the server forks once for
every client connection, sites may choose to limit
the hosts which can query the server for news.
Further, some sites may not wish to allow
certain hosts to post news.
Such limiting can be accomplished through an
access file, usually
.I /usr/spool/news/lib/nntp_access.
This file consists of three fields in the following form:
.sp
.nf
host/net	read/xfer/no	post/no
.fi
.sp
where
.f
.I host
is a valid host name as found in
.I /etc/services,
.I net
is a valid network name as found in
.I /etc/networks,
.I ``read'',
.I ``xfer'',
.I ``post'',
and
.I ``no''
are the corresponding string constants.
Anything to the right of a `#' character
is taken to be a comment and is ignored.
.PP
The presence of an entry in this file
implies that specific host, or
hosts on the named network, are
allowed to read news, but not to post news.
The absence of a entry corresponding
to a client's host or network implies that the client
is not allowed to read or post news.
However, default permissions can be set by having the
first entry in the file be a host/net name of
``default''.
If this is used, ``default'' must be the
first entry.
.PP
The field to the right of the host/net entry
specifies the read access of the host/net in
question.
If the entry is ``read,'' matching
hosts can both read and transfer news.
If the entry is ``xfer,'' however,
matching hosts can only execute transfer
commands (such as NEWNEWS, NEWGROUPS, IHAVE,
and ARTICLE with message-id parameters).
The string ``no'' denies read permission
of any kind to a matching host.
.PP
The next field to the right defines
whether a matching host has post
permission: if the field is ``post''
then the POST command is permitted; if
the field is ``no,'' then matching clients
are not allowed to post news.
.PP
.I Nntpd
is selective and searches for a ``best match''
when searching this file to check its client's
permissions.  That is, a specific host name
match is used over a
client being a member of a specified net.
.I Nntpd
does not know about subnets.
.SH EXAMPLE ACCESS FILE
.PP
.sp
.nf
#
# Example access file
#
default		xfer	no
ucb-ether	read	post
shadow		no	no
.fi
.sp
.PP
The above file would set a default condition allowing
transfer of news, but no reading or posting.
Hosts on the network ``ucb-ether'' would be able to
read and post news.
Finally, the host ``shadow'' would not be allowed
to read or post news.
.SH
NEWGROUPS
.PP
In order to efficiently implement the NEWGROUPS command, the
server expects to find a file, typically
.I /usr/spool/news/lib/groupdates,
which has a list of active newsgroups and when they
were created.
.PP
This file is created and updated a certain number of times a day
by the program
.IR mkgrdates (8C),
which scans the active file and decides whether or not
to update the ``groupdates'' file.  This program
is not spawned by
.I nntpd,
and must be run by
.IR cron (1).
.SH AUTHOR
Phil Lapsley (ARPA: phil@berkeley.edu; UUCP: ...!ucbvax!phil)
.SH SEE ALSO
cron(1),
inetd(8C),
mkgrdates(8C),
mkhistdates(8C)
.PP
RFC 977, ``Network News Transfer Protocol:
A Proposed Standard for the Stream Based Transmission
of News Articles.''
.SH BUGS
Should understand subnetworks in the access file.