Provided by: inn2_2.6.4-2build4_amd64 
NAME
innd - InterNetNews daemon
SYNOPSIS
innd [-aCdfNrsSu] [-4 address] [-6 address] [-c days] [-H count] [-i count] [-l size] [-m mode] [-n flag]
[-o count] [-P port] [-t timeout] [-T count] [-X seconds]
DESCRIPTION
innd, the InterNetNews daemon, handles all incoming NNTP feeds, coordinates the storage, retransmission,
and overview generation for all accepted articles, and manages the active(5) and history(5) databases.
It handles incoming connections on the NNTP port, and also creates and listens to a local Unix-domain
stream socket in order to receive articles from local processes such as nnrpd(8) and rnews(1).
As the master daemon, innd should generally be started at boot and be always running. It listens to a
Unix-domain datagram socket for commands to control its activities, commands that can be sent using
ctlinnd(8). The current status of innd can be obtained by running "ctlinnd mode", or for more detailed
output, innstat(8).
innd can be in one of three operating modes: running, paused, or throttled. Running is the normal mode;
when the server is throttled, it closes connections and rejects new ones. Paused is like a temporary
throttle, suspending innd's activities but not causing the server to shut down existing connections. The
mode is normally changed via ctlinnd(8), either by various automated processes (such as nightly article
expiration) or manually by the news administrator, but innd will also throttle itself if it encounters
ENOSPC errors in writing data or an excessive number of I/O errors (among other problems).
innd normally takes care of spawning nnrpd(8) to handle connections from news reading clients, but it can
be run on a separate port from nnrpd(8) so that feed connections and news reading connections are handled
separately (this can often be faster). Normally, innd listens on port 119, the assigned port for NNTP;
if it is desirable to run innd and nnrpd(8) on separate ports, it's recommended that nnrpd(8) be given
port 119 (since many news reading clients connect only to that port) and that port 433 be used for innd.
The primary configuration files that control innd's activities are incoming.conf, which specifies what
remote sites innd will accept connections from, newsfeeds, which specifies what is to be done with
incoming articles besides storing them, and inn.conf, which sets a wide variety of configuration
parameters. Some parameters in inn.conf(5) can also be set with command-line flags; for these, the
command-line flags take precedence if used.
innd must be run as the news user and news group. It will check for this at startup and fail to start if
not run properly. Normally it should be started via rc.news(8) as part of the system boot up process.
It relies on the setuid root helper program innbind(8) to listen on a privileged port (119, 433 or 563).
OPTIONS
For the options below that override inn.conf settings, see inn.conf(5) for the default values if neither
the inn.conf setting nor the command-line option is given.
-4 address
Normally, innd binds to all local IP addresses (unless bindaddress is set in inn.conf). If this
option is given, it specifies the IP address that INN should bind as. This is only relevant for
servers with multiple local IP addresses. The IP address must be in dotted-quad ("nnn.nnn.nnn.nnn")
format.
If this option is specified, it's the same as setting bindaddress in inn.conf and may cause changes
in whether INN binds to an IPv6 address as well. See inn.conf(5) for more details and also the -6
flag for innd.
This option has no effect when systemd socket activation is used.
-6 address
Only applies when INN has been built with IPv6 support. Normally innd binds to all local IP
addresses (unless bindaddress6 is set in inn.conf). If this option is given, it specifies the IPv6
address that INN should bind to. The IPv6 address must be in colon-separated RFC 4291 format
("n:n:n:n:n:n:n:n").
If this option is specified, it's the same as setting bindaddress6 in inn.conf and may cause changes
in whether INN binds to an IPv4 address as well. See inn.conf(5) for more details and also the -4
flag for innd.
This option has no effect when systemd socket activation is used.
-a By default, if a host connects to innd but is not listed in incoming.conf, the connection is handed
off to nnrpd (or rejected if noreader is set in inn.conf). If -a is given, incoming.conf is ignored
and any host can connect and transfer articles. This flag should never be used with an accessible
server connected to Usenet; it would open the server up for all sorts of abuse.
-c days
innd normally rejects any article that is older (in days) than the value of artcutoff in inn.conf.
This option, if given, overrides the value of that setting. If days is 0, this check is suppressed
and innd will accept articles regardless of how old they are.
-C This flag tells innd to accept and propagate but not actually process cancel or supersedes messages.
This is intended for sites concerned about abuse of cancels, or that wish to use another cancel
mechanism with stronger authentication.
-d, -f
innd normally puts itself into the background, points its standard output and error to log files, and
disassociates itself from the terminal. Using -d prevents all of this, resulting in log messages
being written to standard output; this is generally useful only for debugging. Using -f prevents the
backgrounding and disassociation but still redirects output; it may be useful if you want to monitor
innd with a program that would be confused by forks.
-H count, -T count, -X seconds
These flags control the number of connections per seconds seconds that are allowed. This code is
meant to protect your server from newsreader clients that make too many connections per minute (and
therefore these flags are probably only useful when innd is spawning nnrpd). You probably should not
use these options unless you're having problems. The table used for this check is fixed at 128
entries and is used as a ring; the size was chosen to make calculating the index easy and to be
fairly sure that it won't run out of space. In practice, it is unlikely that even half the table
will be used at any given moment.
The -H flag limits the number of times a host is allowed to connect to the server per the time
interval given by -X. The default is 2.
The -T flag limits the total number of incoming connections per the time interval given by -X. The
maximum value is 128, and the default is 60.
Note that the time interval given by -X is set to 0 by default, that is to say no control is done on
the number of connections.
-i count
innd normally allows a maximum number of concurrent NNTP connections given by the value of
maxconnections in inn.conf. This option, if given, overrides the value of that setting. If count is
0, this check is suppressed.
-l size
innd normally rejects any article larger than the value of maxartsize in inn.conf. This option, if
given, overrides the value of that setting and specifies a maximum article size of size. If size is
0, this check is suppressed.
-m mode
Normally, innd starts in the "running" mode. If this option is given, it specifies what mode innd
should start in. mode should begin with one of "g", "p", or "t", and the starting mode will be set
to "running", "paused", or "throttled", respectively, based on that initial letter. ("g" is short
for "go".)
-N If this option is given, any filters (Perl or Python) are disabled before innd starts (normally,
filters default to being enabled). The filters can be enabled after innd has started with
ctlinnd(8).
-n flag
Whether innd allows (and hands off to nnrpd) reader connections while paused or throttled is normally
determined by the value of readerswhenstopped in inn.conf. This option, if given, overrides that
value. If flag is "n", innd will not allow readers if it is paused or throttled. If flag is "y",
readers will be allowed regardless of innd's operating mode.
-o count
This flag limits the number of file descriptors that are available for outgoing file feeds. The
default is the number of available file descriptors minus some reserved for internal use (which could
potentially starve innd of descriptors to use for accepting new connections). If innd has more file
feeds than count, some of them will be buffered and only written out periodically.
Normally you never need to use this option, since the number of outgoing feeds is fixed, being the
number of file feeds configured in newsfeeds, and is generally small (particularly given that
innfeed(8) is now used for most outgoing feeds at large sites).
-P port
The port innd should listen on is normally given by the value of port in inn.conf. This option, if
given, overrides that value and specifies the port that innd should bind to.
-r Instructs innd to renumber the active file after starting, just as if a "ctlinnd renumber" command
were sent.
-s Just check the syntax of the newsfeeds file and exit. innd will exit with a non-zero status if any
errors are found; the actual errors will be reported via syslog(3).
-S Report errors found in incoming.conf via syslog(3) and exit normally. (Yes, this is less useful than
it should be.)
-t seconds
Normally, innd will flush any changes to history and the active file after 300 seconds of inactivity.
This option changes that timeout to seconds.
-u The news log (the trace information for every article accepted by innd) is normally buffered. This
option changes the log to be unbuffered.
CONTROL MESSAGES
Arriving articles that have a Control: header are called "control messages". Except for cancel messages,
these messages are handled by controlchan(8) via a feed set up in newsfeeds.
(Cancel messages update the history database, so they must be handled internally; the cost of syncing,
locking, then unlocking would be too high given the number of cancel messages that are received. Note
that if an article is cancelled before it is received by the news server, it will be rejected when it
arrives since the history database has been updated; it is useful for rejecting spam before it arrives.)
The distribution of control messages is different than that of standard articles. Control messages are
normally filed into the pseudo-newsgroup named "control" regardless of which newsgroup they were actually
posted to. If, however, a "control."command newsgroup exists that matches the control command, the
control message will be filed into that group instead. For example, a newgroup control message will be
filed in "control.newgroup" if that group exists; otherwise, it will be filed in "control".
If you want to specifically feed all control messages to a given site regardless of whether the control
messages would affect the newsgroups you're feeding that site, you can put the appropriate control
newsgroup in the subscription list. For example, to feed all cancel messages to a given remote site
(normally a bad idea), add "control.cancel" to its subscription list. Normally it's best to exclude the
control newsgroups from feeds to keep from sending your peers more control messages than they care about.
That's why the newsfeeds pattern "!control,!control.*" is as often as not specified (adding this pattern
do not prevent control messages which affect the newsgroups fed to a site from being sent to it).
checkgroups, newgroup and rmgroup control messages receive additional special treatment. If one of these
control messages is approved and posted to the newsgroup being created or removed (or to the admin group
to which the checkgroups is posted), the message will be sent to all sites whose subscription patterns
would cause them to receive articles posted to that group. For example, if a newgroup control message
for a nonexistent newsgroup "news.admin.meow" is received, it will be sent to any site whose subscription
pattern would cause it to receive "news.admin.meow" if that newsgroup existed (such as a pattern of
"news.admin.*"). For this reason, it is correct to post newgroup messages to the newsgroup that the
control message would create. It is not generally correct to crosspost newgroup messages to some "well-
propagated" newsgroup; not only will this not actually improve their propagation to sites that want such
control messages, but it will also cause sites that do not want those control messages to receive them.
Therefore, assuming that a newgroup control message is sent to the group "news.admin.meow" (specified in
the Newsgroups: header) in order to create the group "news.admin.meow", the sites with the following
subscription patterns will receive it:
*,@news.*
news.*
news.*,!control,!control.*
control,control.*
As a matter of fact, for the first pattern, "control.newgroup" (or "control") is included in "*".
However, the sites with the following subscription patterns will not receive it:
*,@news.*,!control,!control.*
comp.*,@news.*
If a control message is posted to a group whose name ends with the four characters ".ctl", this suffix is
stripped off and the control message is propagated as if it were posted to the base group. For example,
a cancel message posted to "news.admin.ctl" will be sent to all sites that subscribe to "control.cancel"
(or "control" if that newsgroup doesn't exist) or "news.admin". This behavior is present for historical
compatibility reasons and should be considered obsolete; support for the ".ctl" suffix may be removed in
a future version of INN.
Finally, articles posted to newsgroups beginning with "to." are treated specially. Provided that either
that newsgroup exists in the active file or mergetogroups is set in inn.conf, the remainder of the
newsgroup is taken to be a site name, as configured in newsfeeds, and the article is sent to that site.
If mergetogroups is set, the article will be filed in the group named "to" (which must exist in the
active file). For example, with mergetogroups set, an article posted to "to.uunet" will be filed in "to"
and sent to the site "uunet".
PROTOCOL DIFFERENCES
innd implements the NNTP commands defined in RFC 3977 (NNTP), RFC 4643 (NNTP authentication), RFC 4644
(streaming NNTP feeds) and RFC 6048 (NNTP LIST additions) with the following differences:
1. A batch transfer command, XBATCH byte-count, is provided. This command will read byte-count bytes
and store them for later processing by rnews(1) (which must be run separately, probably from cron).
See innxbatch(8) and sendxbatches for more details on this extension.
2. As INN is a mode-switching news server, innd implements a limited subset of the protocol useful for
transferring news. The remaining commands are mostly only useful for readers and are implemented by
nnrpd(8). Use of the MODE READER command will cause innd to pass the connection to nnrpd.
3. innd allows a wider syntax for wildmats.
4. Three commands (IHAVE, CHECK and TAKETHIS) will continue, for interoperability reasons, to return a
reject code (respectively 435, 438 and 439) when the command contains a syntax error (which normally
leads to 501).
HEADER MODIFICATIONS
innd modifies as few article headers as possible, although it could be better in this area.
Empty headers and headers that consist of nothing but whitespace are dropped.
The local site's name (as set with the pathhost parameter in inn.conf) and an exclamation point are
prepended to the Path: header, provided the first site name in the Path: header is different from the
local one. In addition, pathalias and pathcluster may be similarly respectively prepended and appended
to the Path: header; see inn.conf(5) for the details.
The Xref: header is removed and a new one created.
innd does not rewrite incorrect headers. For example, it will not replace an incorrect Lines: header,
though it may reject such an article depending on the value of linecountfuzz in inn.conf.
CANCEL FEEDS
In order to efficiently apply a large number of local cancels (such as from processing NoCeMs or from
some other external source), INN supports a special feed mode available only to connections to the local
Unix-domain socket (not to connections to any network sockets).
To enter this mode, connect to the Unix-domain socket (pathrun/nntpin) and send the command MODE CANCEL.
The response will have code 284. Every subsequent line sent on that connection should consist of a
single message-ID. An attempt will be made to cancel that message-ID, and the server will reply 289 for
success or 484 for failure. (Failure can occur, for example, if the server is paused or throttled, or
the message-ID is corrupt. Failure does not occur if the article to be cancelled does not exist.)
LOGGING
innd reports all incoming articles in its log file (pathlog/news). This is a text file with a variable
number of space-separated fields in one of the following formats:
mon dd hh:mm:ss.mmm + feed <message-id> site ...
mon dd hh:mm:ss.mmm j feed <message-id> site ...
mon dd hh:mm:ss.mmm c feed <message-id> Cancelling <message-id>
mon dd hh:mm:ss.mmm - feed <message-id> reason
mon dd hh:mm:ss.mmm ? feed <message-id> reason
There may also be hostname and/or size fields after the message-ID depending on the settings of
nntplinklog and logartsize in inn.conf.
The first three fields are the date and time to millisecond resolution. The fifth field is the site that
sent the article (based on the Path: header) and the sixth field is the article's message-ID; they will
be a question mark if the information is not available.
The fourth field indicates whether the article was accepted or not. If it is a plus sign, then the
article was accepted. If it is the letter "j", then the article was accepted, providing all of the
newsgroups to which the article was posted were set to status "j" in the active file (or not listed in
the active file and wanttrash was set in inn.conf), and then the article was filed into the "junk"
newsgroup. In both of these cases, the article has been accepted and the "site ..." field contains the
space-separated list of sites to which the article is being sent.
If the fourth field is the letter "c", then a cancel message was accepted before the original article
arrived, and a history entry for the cancelled message was created so that innd will reject that message
if it arrives later.
If the fourth field is a minus sign, then the article was rejected. The reasons for rejection generated
by innd include:
"%s" header too long
Article exceeds local limit of %s bytes
Article posted in the future -- "%s"
Bad "%s" header
Can't write history
Duplicate
Duplicate "%s" header
EOF in headers
Linecount %s != %s +- %s
Missing %s header
No body
No colon-space in "%s" header
No matching newsgroups in cancel <%s>
No space
Space before colon in "%s" header
Too old -- "%s"
Unapproved for "%s"
Unwanted newsgroup "%s"
Unwanted distribution "%s"
Whitespace in "Newsgroups" header -- "%s"
where %s, above, is replaced by more specific information. (The Perl and Python filters, if used, may
reject articles with other reasons.)
If the fourth field is the letter "?", the article contains strange strings, such as CR without LF or LF
without CR. (These characters should never occur in isolation, only together as CRLF to indicate the end
of a line.) This log message is just informational, to give an idea of how widespread such articles are;
innd does not reject such articles.
Note that when wanttrash is set to true in inn.conf and an article is received that isn't posted to any
valid newsgroups, it will be accepted and logged with two lines, a "j" line and a minus sign line, unless
the logtrash parameter is set to false (in which case only the "j" line is written).
innd also makes extensive reports through syslog(3). The first word of the log message will be the name
of the site if the entry is site-specific (such as a "connected" message). The first word will be
"SERVER" if the message relates to the server itself, such as when a read error occurs.
If the second word is the four letters "cant", then an error is being reported. (The absence of an
apostrophe is intentional; it makes it easier to grep from the command line and easier to find error
messages in FAQs using a search engine. However, "can't" is also used at a few places.) In this case,
the next two words generally name the system call or library routine that failed and the object upon
which the action was being performed. The rest of the line may contain other information.
In other cases, the second word attempts to summarize what change has been made, while the rest of the
line gives more specific information. The word "internal" generally indicates an internal logic error.
SIGNALS
innd will catch SIGTERM and SIGHUP and shut down. If -d is used, SIGINT will also be caught and will
result in an orderly shutdown.
innd will catch the SIGUSR1 signal and recreate the control channel used by ctlinnd(8).
BUGS
innd normally attempts to strip IP options from incoming connections, since it uses IP-based
authentication and source routing can confuse that. However, this doesn't work on all systems, and it
doesn't work at all in the presence of IPv6 support (and is disabled in that case). Hence, if using innd
with IPv6 support, make sure that your kernel or router disables source routing.
HISTORY
Written by Rich $alz <rsalz@uunet.uu.net> for InterNetNews.
$Id: innd.pod 10523 2021-01-17 21:52:00Z iulius $
SEE ALSO
active(5), ctlinnd(8), dbz(3), history(5), incoming.conf(5), inn.conf(5), innbind(8), innfeed(8),
innstat(8), newsfeeds(5), nnrpd(8), rnews(1), syslog(3).