nnrpd - NNTP server for reader clients
nnrpd [-DfnoSt] [-4 address] [-6 address] [-b address] [-c configfile]
[-i initial] [-I instance] [-p port] [-P prefork] [-r reason] [-s
nnrpd is an NNTP server for newsreaders. It accepts commands on its
standard input and responds on its standard output. It is normally
invoked by innd(8) with those descriptors attached to a remote client
connection. nnrpd also supports running as a standalone daemon.
Unlike innd(8), nnrpd supports all NNTP commands for user-oriented
reading and posting. nnrpd uses the readers.conf file to control who
is authorized to access the Usenet database.
On exit, nnrpd will report usage statistics through syslog(3).
nnrpd only reads config files (both readers.conf and inn.conf) when it
is spawned. You can therefore never change the behavior of a client
that’s already connected. If nnrpd is run from innd (the default) or
from inetd(8), xinetd(8), or some equivalent, a new nnrpd process is
spawned for every connection and therefore any changes to configuration
files will be immediately effective for all new connections. If you
are instead running nnrpd with the -D option, any configuration changes
won’t take effect until nnrpd is restarted.
The inn.conf setting nnrpdflags can be used to pass any of the options
below to instances of nnrpd that are spawned directly from innd. Many
options only make sense when -D is used, so these options should not be
used with nnrpdflags. See also the discussion of nnrpdflags in
When nnrpdloadlimit in inn.conf is not 0, it will also reject
connections if the load average is greater than that value (typically
16). nnrpd can also prevent high-volume posters from abusing your
resources. See the discussion of exponential backoff in inn.conf(5).
The -4 parameter instructs nnrpd to bind to the specified IPv4
address when started as a standalone daemon using the -D flag.
This has to be a valid IPv4 address belonging to an interface of
the local host. It can also be 0.0.0.0, saying to bind to all
addresses (this is the default).
The -6 parameter instructs nnrpd to bind to the specified IPv6
address when started as a standalone daemon using the -D flag.
This has to be a valid IPv6 address belonging to an interface of
the local host. It can also be "::0", saying to bind to all IPv6
By default, nnrpd in daemon mode listens to both IPv4 and IPv6
addresses. With this option, it will listen only to the specified
IPv6 addresses. On some systems however, a value of "::0" will
cause it to listen to all IPv4 addresses as well.
Similar to the -4 flag. -b is kept for backwards compatibility.
By default, nnrpd reads the readers.conf to determine how to
authenticate connections. The -c flag specifies an alternate file
for this purpose. If the file name isn’t fully qualified, it is
taken to be relative to pathetc in inn.conf. (This is useful to
have several instances of nnrpd running on different ports or IP
addresses with different settings.)
-D If specified, this parameter causes nnrpd to operate as a daemon.
That is, it detaches itself and runs in the background, forking a
process for every connection. By default, nnrpd listens on the
NNTP port (119), so either innd(8) has to be started on another
port or the -p parameter used. Note that with this parameter,
nnrpd continues running until killed. This means that it reads
inn.conf once on startup and never again until restarted. nnrpd
should therefore be restarted if inn.conf is changed.
When started in daemon mode, nnrpd will write its PID into a file
in the pathrun directory. The file will be named nnrpd.pid if
nnrpd listens on port 119 (default), or nnrpd-%d.pid, where %d is
replaced with the port that nnrpd is configured to listen on (-p
option is given and its argument is not 119).
-f If specified, nnrpd does not detach itself and runs in the
foreground when started as a standalone daemon using the -D flag.
Specify an initial command to nnrpd. When used, initial is taken
as if it were the first command received by nnrpd. After having
responded, nnrpd will close the connection.
If specified, instance is used as an additional static portion
within message-IDs generated by nnrpd; typically this option would
be used where a cluster of machines exist with the same virtual
hostname and must be disambiguated during posts.
-n The -n flag turns off resolution of IP addresses to names. If you
only use IP-based restrictions in readers.conf and can handle IP
addresses in your logs, using this flag may result in some
-o The -o flag causes all articles to be spooled instead of sending
them to innd(8). rnews with the -U flag should be invoked from
cron on a regular basis to take care of these articles. This flag
is useful if innd(8) is accepting articles and nnrpd is started
standalone or using inetd(8).
The -p parameter instructs nnrpd to listen on port when started as
a standalone daemon using the -D flag.
The -P parameter instructs nnrpd to prefork prefork children
awaiting connections when started as a standalone daemon using the
If the -r flag is used, then nnrpd will reject the incoming
connection giving reason as the text. This flag is used by innd(8)
when it is paused or throttled. reason should be encoded in UTF-8.
As each command is received, nnrpd tries to change its "argv" array
so that ps(1) will print out the command being executed. To get a
full display, the -s flag may be used with a long string as its
argument, which will be overwritten when the program changes its
-S If specified, nnrpd will start a negotiation for a TLS session as
soon as connected. To use this flag, --with-openssl must have been
specified at configure time. For more information on running nnrpd
with TLS support, see "TLS SUPPORT".
-t If the -t flag is used, then all client commands and initial
responses will be traced by reporting them in syslog. This flag is
set by innd(8) under the control of the ctlinnd(8) "trace" command,
and is toggled upon receipt of a SIGHUP; see signal(2).
If INN is built with --with-openssl, nnrpd will support news reading
over TLS (also known as SSL). For clients that use the STARTTLS
command, no special configuration is needed beyond creating a TLS/SSL
certificate for the server. You should do this in exactly the same way
that you would generate a certificate for a web server.
If you’re happy with a self-signed certificate (which will generate
warnings with some news reader clients), you can create and install one
in the default path by running "make cert" after "make install" when
installing INN, or by running the following commands:
openssl req -new -x509 -nodes -out <pathetc>/cert.pem \
-days 366 -keyout <pathetc>/key.pem
chown news:news <pathetc>/cert.pem
chmod 640 <pathetc>/cert.pem
chown news:news <pathetc>/key.pem
chmod 600 <pathetc>/key.pem
Replace the paths with something appropriate to your INN installation.
This will create a self-signed certificate that will expire in a year.
The openssl program will ask you a variety of questions about your
organization. Enter the fully qualified domain name of the server as
the name the certificate is for.
You then have to set these inn.conf parameters with the right paths:
In case you have a certificate authority root certificate, you can also
set tlscafile to its path.
Most news clients currently do not use the STARTTLS command, however,
and instead expect to connect to a separate port (563) and start a TLS
negotiation immediately. innd does not, however, know how to listen
for connections to that port and then spawn nnrpd the way that it does
for regular reader connections. You will therefore need to arrange for
nnrpd to listen on that port through some other means. This can be
done with the -D flag along with "-p 563" and put into your init
su news -c '<pathbin>/nnrpd -D -p 563 -S'
but the easiest way is probably to add a line like:
nntps stream tcp nowait news <pathbin>/nnrpd nnrpd -S
to /etc/inetd.conf or the equivalent on your system and let inetd run
nnrpd. (Change the path to nnrpd to match your installation.) You may
need to replace "nntps" with 563 if "nntps" isn’t defined in
/etc/services on your system.
nnrpd implements the NNTP commands defined in RFC 3977 (NNTP), RFC 4642
(TLS/NNTP) and RFC 4643 (NNTP authentication) with the following
1. Besides the keywords defined in RFC 3977 (ACTIVE, ACTIVE.TIMES,
DISTRIB.PATS, HEADERS, NEWSGROUPS and OVERVIEW.FMT), the LIST
command may be followed by the optional keywords COUNTS,
DISTRIBUTIONS, MODERATORS, MOTD and SUBSCRIPTIONS to respectively
get an improved version of the ACTIVE variant with the number of
articles in every newsgroup, a list of valid distributions, the
moderators list, the message of the day information for readers,
and a list of recommended group subscriptions.
2. The XGTITLE [wildmat] command is provided. This extension is used
by ANU-News and documented in RFC 2980. It returns a 282 reply
code, followed by a one-line description of all newsgroups that
match the pattern. The default is the current group.
Note that LIST NEWSGROUPS should be used instead of XGTITLE.
3. The XHDR header [message-ID|range] command is implemented. It
returns a 221 reply code, followed by specific headers for the
specified range; the default is to return the data for the current
article. See RFC 2980.
Note that HDR should be used instead of XHDR.
4. The XOVER [range] command is provided. It returns a 224 reply
code, followed by the overview data for the specified range; the
default is to return the data for the current article. See
Note that OVER should be used instead of XOVER.
5. A new command, XPAT header message-ID|range pattern [pattern ...],
is provided. The first argument is the case-insensitive name of
the header to be searched. The second argument is either an
article range or a single message-ID, as specified in RFC 2980.
The third argument is a uwildmat(3)-style pattern; if there are
additional arguments, they are joined together separated by a
single space to form the complete pattern. This command is similar
to the XHDR command. It returns a 221 response code, followed by
the text response of all article numbers that match the pattern.
6. A newsgroup name is case-sensitive for nnrpd.
7. If IHAVE has been advertised, it will not necessarily be advertised
for the entire session (contrary to section 3.4.1 of RFC 3977).
nnrpd only advertises the IHAVE capability when it is really
8. nnrpd allows a wider syntax for wildmats and ranges (especially "-"
Written by Rich $alz <email@example.com> for InterNetNews. Overview
support added by Rob Robertston <firstname.lastname@example.org> and Rich in
January, 1993. Exponential backoff (for posting) added by Dave Hayes
in Febuary 1998.
$Id: nnrpd.pod 8956 2010-02-08 20:50:47Z iulius $
ctlinnd(8), innd(8), inn.conf(5), readers.conf(5), signal(2),