Ubuntu Manpage: nnrpd - NNTP server for reader clients

NAME

       nnrpd - NNTP server for reader clients

SYNOPSIS

       nnrpd [-DfnoSt] [-4 address] [-6 address] [-b address] [-c configfile] [-i initial] [-I instance] [-p
       port] [-P prefork] [-r reason] [-s padding]

DESCRIPTION

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 inn.conf(5).

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).

OPTIONS

-4 address
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).

-6 address
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 addresses.

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.

-b address
Similar to the -4 flag. -b is kept for backwards compatibility.

-c configfile
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.

-i initial
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.

-I instance
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 additional
speed.

-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).

-p port
The -p parameter instructs nnrpd to listen on port when started as a standalone daemon using the -D
flag.

-P prefork
The -P parameter instructs nnrpd to prefork prefork children awaiting connections when started as a
standalone daemon using the -D flag.

-r reason
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.

-s padding
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 title.

-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).

TLS SUPPORT

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:

umask 077
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:

tlscapath: <pathetc>
tlscertfile: <pathetc>/cert.pem
tlskeyfile: <pathetc>/key.pem

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 scripts:

su news -s /bin/sh -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.

PROTOCOL DIFFERENCES

nnrpd implements the NNTP commands defined in RFC 3977 (NNTP), RFC 4642 (TLS/NNTP), RFC 4643 (NNTP
authentication) and RFC 6048 (NNTP LIST additions) with the following differences:

1. 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.

2. 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.

3. 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 RFC 2980.

Note that OVER should be used instead of XOVER.

4. 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.

5. A newsgroup name is case-sensitive for nnrpd.

6. 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
available.

7. nnrpd allows a wider syntax for wildmats and ranges (especially "-" and "-article-number").

HISTORY

       Written by Rich $alz <rsalz@uunet.uu.net> for InterNetNews.  Overview support added by Rob Robertston
       <rob@violet.berkeley.edu> and Rich in January, 1993.  Exponential backoff (for posting) added by Dave
       Hayes in Febuary 1998.

       $Id: nnrpd.pod 9138 2010-10-29 18:09:50Z iulius $