INND(8) InterNetNews Documentation INND(8)
innd - InterNetNews daemon
innd [-aCdfNrsu] [-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]
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).
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.
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.
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.
-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.
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.
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.
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.
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.
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).
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.
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).
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).
Normally, innd will flush any changes to history and the active file after 300 seconds of inactivity. This option changes that timeout
-u The news log (the trace information for every article accepted by innd) is normally buffered. This option changes the log to be
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:
but the sites with the following subscription patterns will not receive it:
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
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".
innd implements the NNTP commands defined in RFC 3977 (NNTP), RFC 4643 (NNTP authentication) and RFC 4644 (streaming) with the following
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).
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.
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.)
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 "%s" header
EOF in headers
Linecount %s != %s +- %s
Missing %s header
No colon-space in "%s" header
No matching newsgroups in cancel <%s>
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
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.
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).
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.
Written by Rich $alz <firstname.lastname@example.org> for InterNetNews.
$Id: innd.pod 9000 2010-03-14 21:03:54Z iulius $
active(5), ctlinnd(8), dbz(3), history(5), incoming.conf(5), inn.conf(5), innbind(8), innfeed(8), innstat(8), newsfeeds(5), nnrpd(8),
INN 2.5.2 2010-03-14 INND(8)