NNTPD(8C) MAINTENANCE COMMANDS NNTPD(8C)
NAME
nntpd - Network News Transfer Protocol server
SYNOPSIS
/etc/nntpd
(with /etc/inetd, see below)
DESCRIPTION
Nntpd is a server that supports the proposed standard for
the stream based transmission of network news articles. It
can be used both by ``reader/poster'' clients that present
news to users, and by ``transfer'' clients that transport
news between machines. When used with Internet TCP, nntpd
operates at the port indicated in the ``nntp'' service entry
in /etc/services; the port number assigned by the Network
Information Center for this service is 119. For use with
DECNET (which is only known to work under ULTRIX), define
the NNTP object with NCP.
ncp define object NNTP number 0 file /etc/nntpd
ncp define object NNTP default user guest type stream
ncp set object NNTP all
This manual page describes nntpd from version 1.5.9 of the
NNTP package.
Nntpd can operate either as a stand-alone server, or as a
server under inetd(8C). For stand-alone use, nntpd must be
compiled with the -DALONE option, and is usually invoked at
system startup by the /etc/rc.local script. Under
inetd(8C), the appropriate entry must be made in
/etc/inetd.conf, and the server must be compiled without the
-DALONE flag. You may need to halt and restart inetd(8C) or
send it SIGHUP to force it to reread /etc/inetd.conf.
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 ( /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 Stan-
dard for the Stream Based Transmission of News Articles.''
CLIENT ACCESS
Sites may choose to limit the hosts that can query the
server for news. Further, some sites may not wish to allow
certain hosts to post news. Finally, some sites may wish to
restrict the newsgroups that can be accessed from remote
hosts. Such limiting can be accomplished through an access
file, /usr/lib/news/nntp_access. This file consists of
three or four fields in the following form:
Amiga Unix Last change: 4 July 1990 1
NNTPD(8C) MAINTENANCE COMMANDS NNTPD(8C)
host/net/*domain.suffix/address read/xfer/both/no post/no newsgroups
where host is a valid host name as found in /etc/hosts, net
is a valid network name as found in /etc/networks,
*.domain.suffix is a valid domain part of a hostname pre-
ceeded by an asterisk, address is a valid internet address
in the form of a dotted quad, and ``read'', ``xfer'',
``both'', ``post'', and ``no'' are the corresponding string
constants. Newsgroups is an optional list of comma
separated newsgroup names. Anything to the right of a `#'
character is taken to be a comment and is ignored.
The presence of an entry in this file implies that specific
host, or hosts on the named network, or hosts with a domain
suffix that matches, 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. 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.
The first 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 read news. This means that
all commands but IHAVE and POST can be executed. If the
entry is ``xfer,'' however, matching hosts can only execute
commands used for transferring news, such as NEWNEWS, NEW-
GROUPS, IHAVE, and ARTICLE with message-id parameters. If
the entry is ``both,'' ths host can execute all commands but
POST. The string ``no'' denies read permission of any kind
to a matching host.
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.
The next field is optional, and, if present, is a comma
separated list of newsgroup names that restrict the client's
reading ability. Clients are not allowed to read or
transfer articles in newsgroup names preceded by an exclama-
tion point. By default, clients are allowed to read all
newsgroups.
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.
EXAMPLE ACCESS FILE
Amiga Unix Last change: 4 July 1990 2
NNTPD(8C) MAINTENANCE COMMANDS NNTPD(8C)
#
# Example access file
#
default xfer no
ucb-ether read post
shadow no no
*.stanford.edu no no
ic read post !ucb.postgres
128.249.1.1 read no
The above file allows only transfer of news (i.e., no read-
ing or posting) by default. Hosts on the network ``ucb-
ether'' would be able to read and post news, however news
transfer would not be allowed. The host ``shadow'' would
not be allowed to read or post news. Hosts that have a
domain suffix of ``.stanford.edu'' are denied access to this
server. The host ``ic'' is allowed to read and post news,
but cannot access articles in the newsgroup ``ucb.postgres''
or any of its child newsgroups (e.g.,
``ucb.postgres.core''). Finally, the host whose ip address
is 128.249.1.1 is allowed to read but not post. If you have
mutl-homed host, all addresses for that host will need to be
listed with the same access information or things will not
work as expected.
INFORMING USERS OF NEW NEWSGROUPS
The NEWGROUPS command does not work well when used with B
news. However, C news provides this information and use of
the NEWGROUPS command will be much more reliable. For those
sites using B news, client programs can determine if new-
groups have been created by testing for the difference in
active file size from the previous session.
Older versions of nntpd relied on the program mkgrdates to
prepare newsgroup creation information. Mkgrdates was fal-
lible and could present a hefty load on the serving system.
Consequently, it is no longer supported, and its use is
discouraged.
AUTHORS
Phil Lapsley (Internet: phil@berkeley.edu; UUCP:
...!ucbvax!phil)
Stan Barber (Internet: sob@tmc.edu; UUCP: ...!bcm!sob)
SEE ALSO
services(5), inetd(8C), rc.local(8)
RFC 977, ``Network News Transfer Protocol: A Proposed Stan-
dard for the Stream Based Transmission of News Articles.''
Amiga Unix Last change: 4 July 1990 3