Commit 2.4.5-5 as unpacked

[innduct.git] / doc / pod / inn.conf.pod

=head1 NAME

inn.conf - Configuration data for InterNetNews programs

=head1 DESCRIPTION

F<inn.conf> in I<pathetc> is the primary general configuration file for
all InterNetNews programs.  Settings which control the general operation
of various programs, as well as the paths to all portions of the news
installation, are found here.  The INNCONF environment variable, if set,
specifies an alternate path to F<inn.conf>.

This file is intended to be fairly static.  Any changes made to it will
generally not affect any running programs until they restart.  Unlike
nearly every other configuration file, F<inn.conf> cannot be reloaded
dynamically using ctlinnd(8); innd(8) must be stopped and restarted for
relevant changes to F<inn.conf> to take effect (C<ctlinnd xexec innd> is
the fastest way to do this.)

Blank lines and lines starting with a number sign (C<#>) are ignored.  All
other lines specify parameters, and should be of the following form:

    <name>: <value>

(Any amount of whitespace can be put after the colon and is optional.)  If
the value contains embedded whitespace or any of the characers C<[]<>"\:>,
it must be enclosed in double quotes ("").  A backslash (C<\>) can be used
to escape quotes and backslashes inside double quotes.  <name> is
case-sensitive; C<server> is not the same as C<Server> or C<SERVER>.
(F<inn.conf> parameters are generally all in lowercase.)

If <name> occurs more than once in the file, the first value is used.
Some parameters specified in the file may be overridden by environment
variables.  Most parameters have default values if not specified in
F<inn.conf>; those defaults are noted in the description of each
parameter.

Many parameters take a boolean value.  For all such parameters, the value
may be specified as C<true>, C<yes>, or C<on> to turn it on and may be any
of C<false>, C<no>, or C<off> to turn it off.  The case of these values is
significant.

This documentation is extremely long and organized as a reference manual
rather than as a tutorial.  If this is your first exposure to INN and
these parameters, it would be better to start by reading other man pages
and referring to this one only when an F<inn.conf> parameter is explicitly
mentioned.  Those parameters which need to be changed when setting up a
new server are discussed in F<INSTALL>.

=head1 PARAMETERS

=head2 General Settings

These parameters are used by a wide variety of different components of
INN.

=over 4

=item I<domain>

This should be the domain name of the local host.  It should not have a
leading period, and it should not be a full host address.  It is used only
if the GetFQDN() routine in libinn(3) cannot get the fully-qualified
domain name by using either the gethostname(3) or gethostbyname(3) calls.
The check is very simple; if either routine returns a name with a period
in it, then it is assumed to have the full domain name.  As this parameter
is rarely used, do not use it to affect the righthand side of
autogenerated Message-IDs; see instead I<virtualhost> and I<domain> in
L<readers.conf>.  The default value is unset.

=item I<innflags>

The flags to pass to innd on startup.  See innd(8) for details on the
possible flags.  The default value is unset.

=item I<mailcmd>

The path to the program to be used for mailing reports and control
messages.  The default is I<pathbin>/innmail.  This should not normally
need to be changed.

=item I<mta>

The command to use when mailing postings to moderators and for the use of
innmail(1).  The message, with headers and an added To: header, will be
piped into this program.  The string C<%s>, if present, will be replaced
by the e-mail address of the moderator.  It's strongly recommended for
this command to include C<%s> on the command line rather than use the
addresses in the To: and Cc: headers of the message, since the latter
approach allows the news server to be abused as a mechanism to send mail
to arbitrary addresses and will result in unexpected behavior.  There is
no default value for this parameter; it must be set in F<inn.conf> or a
fatal error message will be logged via syslog.

For most systems, C</usr/lib/sendmail -oi -oem %s> (adjusted for the
correct path to sendmail) is a good choice.

=item I<pathhost>

What to put into the Path: header to represent the local site.  This is
added to the Path: header of all articles that pass through the system,
including locally posted articles, and is also used when processing some
control messages and when naming the server in status reports.  There is
no default value; this parameter must be set in F<inn.conf> or INN will
not start.  A good value to use is the fully-qualified hostname of the
system.

=item I<server>

The name of the default NNTP server.  If I<nnrpdposthost> is not set and
UNIX domain sockets are not supported, nnrpd(8) tries to hand off
locally-posted articles through an INET domain socket to this server.
actsync(8), nntpget(8), and getlist(8) also use this value as the default
server to connect to.  In the latter cases, the value of the NNTPSERVER
environment variable, if it exists, overrides this.  The default value is
unset.

=back

=head2 Feed Configuration

These parameters govern incoming and outgoing feeds:  what size of
articles are accepted, what filtering and verification is performed on
them, whether articles in groups not carried by the server are still
stored and propagated, and other similar settings.

=over 4

=item I<artcutoff>

Articles older than this number of days are dropped.  This setting should
probably match the setting on the C</remember/> line in F<expire.ctl>.
The default value is C<10>.

=item I<bindaddress>

Which IP address innd(8) should bind itself to.  This must be in
dotted-quad format (nnn.nnn.nnn.nnn).  If set to C<all> or not set, innd
defaults to listening on all interfaces.  The value of the
INND_BIND_ADDRESS environment variable, if set, overrides this setting.
The default value is unset.

=item I<bindaddress6>

Like I<bindaddress> but for IPv6 sockets. If only one of the I<bindaddress>
and I<bindaddress6> parameters is used, then only the socket for the
corresponding address family is created. If both parameters are used
then two sockets are created. If neither of them is used, the list of
sockets to listen on will be determined by the system library
I<getaddrinfo(3)> function.  The value of the INND_BIND_ADDRESS6, if set,
overrides this setting.  The default value is unset.

Note that you will generally need to put double quotes ("") around this
value if you set it, since IPv6 addresses contain colons.

=item I<hiscachesize>

If set to a value other than C<0>, a hash of recently received message IDs
is kept in memory to speed history lookups.  The value is the amount of
memory to devote to the cache in kilobytes.  The cache is only used for
incoming feeds and a small cache can hold quite a few message IDs, so
large values aren't necessarily useful unless you have incoming feeds that
are badly delayed.  A good value for a system with more than one incoming
feed is C<256>; systems with only one incoming feed should probably leave
this at C<0>.  The default value is C<0>.

=item I<ignorenewsgroups>

Whether newsgroup creation control messages (newgroup and rmgroup) should
be fed as if they were posted to the newsgroup they are creating or
deleting rather than to the newsgroups listed in the Newsgroups: header.
If this parameter is set, the newsgroup affected by the control message
will be extracted from the Control: header and the article will be fed as
if its Newsgroups: header contained solely that newsgroup.  This is useful
for routing control messages to peers when they are posted to irrelevant
newsgroups that shouldn't be matched against the peer's desired newsgroups
in F<newsfeeds>.  This is a boolean value and the default is false.

=item I<immediatecancel>

When using the timecaf storage method, article cancels are normally just
cached to be cancelled, not cancelled immediately.  If this is set to
true, they will instead by cancelled as soon as the cancel is processed.
This is a boolean value and the default is false.

This setting is ignored unless the timecaf storage method is used.

=item I<linecountfuzz>

If set to something other than C<0>, the line count of the article is
checked against the Lines: header of the article (if present) and the
artice is rejected if the values differ by more than this amount.  A
reasonable setting is C<5>, which is the standard maximum signature length
plus one (some injection software calculates the Lines: header before
adding the signature).  The default value is C<0>, which tells INN not to
check the Lines: header of incoming articles.

=item I<maxartsize>

The maximum size of article (headers and body) that will be accepted by
the server, in bytes.  A value of C<0> allows any size of article, but
note that B<innd> will crash if system memory is exceeded.  The default
value is C<1000000> (approximately 1 MB).  See also I<localmaxartsize>.

=item I<maxconnections>

The maximum number of incoming NNTP connections innd(8) will accept.  The
default value is C<50>.

=item I<pathalias>

If set, this value is prepended to the Path: header of accepted posts
(before I<pathhost>) if it doesn't already appear in the Path: header.
The main purpose of this parameter is to configure all news servers within
a particular organization to add a common identity string to the
Path: header.  The default value is unset.

=item I<pathcluster>

If set, this value is appended to the Path: header of accepted posts
(after I<pathhost>) if it isn't already present as the last element
of the Path: header.  The main purpose of this parameter is to make
several news servers appear as one server.  The default value is unset.

Note that the Path: header reads right to left, so appended means inserted
at the leftmost side of the Path: header.

=item I<pgpverify>

Whether to enable PGP verification of control messages other than cancel.
This is a boolean value and the default is based on whether configure found
pgp, pgpv, or gpgv.

=item I<port>

What TCP port innd(8) should listen on.  The default value is C<119>, the
standard NNTP port.

=item I<refusecybercancels>

Whether to refuse all articles whose message IDs start with
C<E<lt>cancel.>.  This message ID convention is widely followed by spam
cancellers, so the vast majority of such articles will be cancels of spam.
This check, if enabled, is done before the history check and the message
ID is not written to the history file.  This is a boolean value and the
default is false.

This is a somewhat messy, inefficient, and inexact way of refusing spam
cancels.  A much better way is to ask all of your upstream peers to not
send to you any articles with C<cyberspam> in the Path: header (usually
accomplished by having them mark C<cyberspam> as an alias for your machine
in their feed configuration).  The filtering enabled by this parameter is
hard-coded; general filtering of message IDs can be done via the embedded
filtering support.

=item I<remembertrash>

By default, innd(8) records rejected articles in history so that, if
offered the same article again, it can be refused before it is sent.  If
you wish to disable this behavior, set this to false.  This can cause a
substantial increase in the amount of bandwidth consumed by incoming news
if you have several peers and reject a lot of articles, so be careful with
it.  Even if this is set to true, INN won't log some rejected articles to
history if there's reason to believe the article might be accepted if
offered by a different peer, so there is usually no reason to set this to
false (although doing so can decrease the size of the history file).  This
is a boolean value and the default is true.

=item I<sourceaddress>

Which local IP address to bind to for outgoing NNTP sockets (used by
innxmit(8) among other programs, but I<not> innfeed(8) -- see
I<bindaddress> in innfeed.conf(5) for that).  This must be in dotted-quad
format (nnn.nnn.nnn.nnn).  If set to C<all> or not set, the operating
system will choose the source IP address for outgoing connections.  The
default value is unset.

=item I<sourceaddress6>

Like I<sourceaddress> but for IPv6 sockets.

=item I<verifycancels>

Set this to true to enable a simplistic check on all cancel messages,
attempting to verify (by simple header comparison) that the cancel message
is from the same person as the original post.  This can't be done if the
cancel arrives before the article does, and is extremely easy to spoof.
While this check may once have served a purpose, it's now essentially
security via obscurity, commonly avoided by abusers, and probably not
useful.  This is a boolean value, and the default is false.

=item I<wanttrash>

Set this to true if you want to file articles posted to unknown newsgroups
(newsgroups not in the F<active> file) into the C<junk> newsgroup rather
than rejecting them.  This is sometimes useful for a transit news server
that needs to propagate articles in all newsgroups regardless if they're
carried locally.  This is a boolean value and the default is false.

=item I<wipcheck>

If INN is offered an article by a peer on one channel, it will return
deferral responses (code 436) to all other offers of that article for this
many seconds.  (After this long, if the peer that offered the article
still hasn't sent it, it will be accepted from other channels.)  The
default value is C<5> and probably doesn't need to be changed.

=item I<wipexpire>

How long, in seconds, to keep track of message IDs offered on a channel
before expiring articles that still haven't been sent.  The default value
is C<10> and probably doesn't need to be changed.

=item I<dontrejectfiltered>

Normally innd(8) rejects incoming articles when directed to do so by any
enabled article filters (Perl, Python, and TCL).  However, this parameter
causes such articles I<not> to be rejected; instead filtering can be
applied on outbound articles.  If this parameter is set, all articles will
be accepted on the local machine, but articles rejected by the filter will
I<not> be fed to any peers specified in F<newsfeeds> with the C<Af> flag.

=back

=head2 Article Storage

These parameters affect how articles are stored on disk.

=over 4

=item I<cnfscheckfudgesize>

If set to a value other than C<0>, the claimed size of articles in CNFS
cycbuffs is checked against I<maxartsize> plus this value, and if larger,
the CNFS cycbuff is considered corrupt.  This can be useful as a sanity
check after a system crash, but be careful using this parameter if you
have changed I<maxartsize> recently.  The default value is C<0>.

=item I<enableoverview>

Whether to write out overview data for articles.  If set to false, INN
will run much faster, but reading news from the system will be impossible
(the server will be for news transit only).  If this option is set to
true, I<ovmethod> must also be set.  This is a boolean value and the
default is true.

=item I<groupbaseexpiry>

Whether to enable newsgroup-based expiry.  If set to false, article expiry
is done based on storage class of storing method.  If set to true (and
overview information is available), expiry is done by newsgroup name.
This affects the format of F<expire.ctl>.  This is a boolean value and the
default is true.

=item I<mergetogroups>

Whether to file all postings to C<to.*> groups in the pseudonewsgroup
C<to>.  If this is set to true, the newsgroup C<to> must exist in the
F<active> file or INN will not start.  (See the discussion of C<to.>
groups in innd(8) under CONTROL MESSAGES.)  This is a boolean value and
the default is false.

=item I<overcachesize>

How many cache slots to reserve for open overview files.  If INN is
writing overview files (see I<enableoverview>), I<ovmethod> is set to
C<tradindexed>, and this is set to a value other than C<0>, INN will keep
around and open that many recently written-to overview files in case more
articles come in for those newsgroups.  Every overview cache slot consumes
two file descriptors, so be careful not to set this value too high.  You
may be able to use the C<limit> command to see how many open file
descriptors your operating system allows.  innd(8) also uses an open file
descriptor for each incoming feed and outgoing channel or batch file, and
if it runs out of open file descriptors it may throttle and stop accepting
new news.  The default value is C<15> (which is probably way too low if
you have a large number of file descriptors available).

This setting is ignored unless I<ovmethod> is set to C<tradindexed>.

=item I<ovgrouppat>

If set, restricts the overview data stored by INN to only the newsgroups
matching this comma-separated list of wildmat expressions.  Newsgroups not
matching this setting may not be readable, and if I<groupbaseexpiry> is
set to true and the storage method for these newsgroups does not have
self-expire functionality, storing overview data will fail.
The default is unset.

=item I<ovmethod>

Which overview storage method to use.  Currently supported values are
C<tradindexed>, C<buffindexed>, and C<ovdb>.  There is no default value;
this parameter must be set if I<enableoverview> is true (the default).

=over 4

=item C<buffindexed>

Stores overview data and index information into buffers, which are
preconfigured files defined in F<buffinedexed.conf>.  C<buffindexed> never
consumes additional disk space beyond that allocated to these buffers.

=item C<tradindexed>

Uses two files per newsgroup, one containing the overview data and one
containing the index.  Fast for readers, but slow to write to.

=item C<ovdb>

Stores data into a Berkeley DB database.  See the ovdb(5) man page.

=back

=item I<hismethod>

Which history storage method to use.  The only currently supported
value is C<hisv6>.  There is no default value; this parameter must
be set.

=over 4

=item C<hisv6>

Stores history data in the INN history v6 format:  history(5) text
file and a number of dbz(3) database files; this may be in true history
v6 format, or tagged hash format, depending on the build
options.  Separation of these two is a project which has not yet been
undertaken.

=back

=item I<storeonxref>

If set to true, articles will be stored based on the newsgroup names in
the Xref: header rather than in the Newsgroups: header.  This affects what
the patterns in F<storage.conf> apply to.  The primary interesting effect
of setting this to true is to enable filing of all control messages
according to what storage class the control pseudogroups are filed in
rather than according to the newsgroups the control messages are posted
to.  This is a boolean value and the default is true.

=item I<useoverchan>

Whether to innd(8) should create overview data internally through
libstorage(3).  If set to false, innd creates overview data by itself.  If
set to true, innd does not create; instead overview data must be created
by overchan(8) from an appropriate entry in F<newsfeeds>.  Setting to true
may be useful, if innd cannot keep up with incoming feed and the
bottleneck is creation of overview data within innd.  This is a boolean
value and the default is false.

=item I<wireformat>

Only used with the tradspool storage method, this says whether to write
articles in wire format.  Wire format means storing articles with C<\r\n> at
the end of each line and with periods at the beginning of lines doubled,
the article format required by the NNTP protocol.  Articles stored in this
format are suitable for sending directly to a network connection without
requiring conversion, and therefore setting this to true can make the
server more efficient.  The primary reason not to set this is if you have
old existing software that looks around in the spool and doesn't
understand how to read wire format.  Storage methods other than tradspool
always store articles in wire format.  This is a boolean value and the
default is false.

=item I<xrefslave>

Whether to act as the slave of another server.  If set, INN attempts to
duplicate exactly the article numbering of the server feeding it by
looking at the Xref: header of incoming articles and assigning the same
article numbers to articles as was noted in the Xref: header from the
upstream server.  The result is that clients should be able to point at
either server interchangeably (using some load balancing scheme, for
example) and see the same internal article numbering.  Servers with this
parameter set should generally only have one upstream feed, and should
always have I<nnrpdposthost> set to hand locally posted articles off to
the master server.  The upstream should be careful to always feed articles
in order (innfeed(8) can have problems with this in the event of a
backlog).  This is a boolean value and the default is false.

=item I<nfswriter>

For servers writing articles, determine whether the article spool is
on NFS storage.  If set, INN attempts to flush articles to the spool
in a more timely manner, rather than relying on the operating system
to flush things such as the CNFS article bitmaps.  You should only set
this parameter if you are attempting to use a shared NFS spool on a
machine acting as a single writer within a cluster.  This is a boolean
value and the default is false.

=item I<nfsreader>

For servers reading articles, determine whether the article spool is
on NFS storage.  If set, INN will attempt to force articles and
overviews to be read directly from the NFS spool rather than from
cached copies.  You should only set this parameter if you are
attempting to use a shared NFS spool on a machine acting a reader a
cluster.  This is a boolean value and the default is false.

=item I<nfsreaderdelay>

For servers reading articles, determine whether the article spool is
on NFS storage.  If I<nfsreader> is set, INN will use the value of
I<nfsreaderdelay> to delay the apparent arrival time of articles to
clients by this amount; this value should be tuned based on the NFS
cache timeouts locally.  This default is 60 (1 minute).

=item I<msgidcachesize>

How many cache slots to reserve for Message ID to storage token
translations.  When serving overview data to clients (NEWNEWS, XOVER
etc.), nnrpd(8) can cache the storage token associated with a Message
ID and save the cost of looking it up in the history file; for some
configurations setting this parameter can save more than 90% of the
wall clock time for a session.  The default value is 10000.

=item I<tradindexedmmap>

Whether to attempt to mmap() tradindexed overviews articles.  Setting
this to true will give better performance on most systems, but some
systems have problems with mmap().  If this is set to false, overviews
will be read into memory before being sent to readers.  This is a
boolean value and the default is true.

=back

=head2 Reading

These parameters affect the behavior of INN for readers.  Most of them are
used by nnrpd(8).  There are some special sets of settings that are broken
out separately after the initial alphabetized list.

=over 4

=item I<allownewnews>

Whether to allow use of the NEWNEWS command by clients.  This command used
to put a heavy load on the server in older versions of INN, but is now
reasonably efficient, at least if only one newsgroup is specified by the
client.  This is a boolean value and the default is true.  If you use the
I<access> parameter in F<readers.conf>, be sure to read about the way it
overrides I<allownewnews>.

=item I<articlemmap>

Whether to attempt to mmap() articles.  Setting this to true will give
better performance on most systems, but some systems have problems with
mmap().  If this is set to false, articles will be read into memory before
being sent to readers.  This is a boolean value and the default is false.

=item I<clienttimeout>

How long (in seconds) a client connection can be idle before it exits.
When setting this parameter, be aware that some newsreaders use the same
connection for reading and posting and don't deal well with the connection
timing out while a post is being composed.  If the system isn't having a
problem with too many long-lived connections, it may be a good idea to
increase this value to C<3600> (an hour).  The default value is C<600>
(ten minutes).

=item I<initialtimeout>

How long (in seconds) B<nnrpd> will wait for the first command from a
reader connection before dropping the connection.  This is a defensive
timeout intended to protect the news server from badly behaved reader
clients that open and abandon a multitude of connections without every
closing them.  The default value is C<10> (ten seconds), which may need to
be increased if many clients connect via slow network links.

=item I<nnrpdcheckart>

Whether B<nnrpd> should check the existence of an article before listing
it as present in response to an NNTP command.  The primary use of this
setting is to prevent nnrpd from returning information about articles
which are no longer present on the server but which still have overview
data available.  Checking the existence of articles before returning
overview information slows down the overview commands, but reduces the
number of "article is missing" errors seen by the client.  This is a
boolean value and the default is true.

=item I<nnrpperlauth>

This parameter is now obsolete; see "Changes to Perl Authentication
Support for nnrpd" in F<doc/hook-perl>.

=item I<nnrppythonauth>

This parameter is now obsolete; see "Changes to Python Authentication and
Access Control Support for nnrpd" in F<doc/hook-python>.

=item I<noreader>

Normally, innd(8) will fork a copy of nnrpd(8) for all incoming
connections from hosts not listed in F<incoming.conf>.  If this parameter
is set to true, those connections will instead be rejected with a 502
error code.  This should be set to true for a transit-only server that
doesn't support readers, or if nnrpd is running in daemon mode or being
started out of inetd.  This is a boolean value and the default is false.

=item I<readerswhenstopped>

Whether to allow readers to connect even if the server is paused or
throttled.  This is only applicable if nnrpd(8) is spawned from innd(8)
rather than run out of inetd or in daemon mode.  This is a boolean value
and the default is false.

=item I<readertrack>

Whether to enable the tracking system for client behavior.  Tracked
information is recorded to I<pathlog>/tracklogs/log-ID, where ID is
determined by nnrpd's PID and launch time.)  Currently the information
recorded includes initial connection and posting; only information about
clients listed in F<nnrpd.track> is recorded.  This is a boolean value and
the default is false.

=item I<nnrpdflags>

When nnrpd(8) is spawned from innd(8), these flags are passed as
arguments to the nnrpd process.  This setting does not affect instances
of nnrpd that are started in daemon mode, or instances that are started
via another listener process such as inetd(8) or xinetd(8).  Shell
quoting and metacharacters are not supported.  This is a string value
and the default is unset.

=item I<nnrpdloadlimit>

If set to a value other than C<0>, connections to nnrpd will be refused
if the system load average is higher than this value.  The default value
is C<16>.

=back

INN has optional support for generating keyword information automatically
from article body text and putting that information in overview for the
use of clients that know to look for it.  The following parameters control
that feature.

This may be too slow if you're taking a substantial feed, and probably
will not be useful for the average news reader; enabling this is not
recommended unless you have some specific intention to take advantage of
it.

=over 4

=item I<keywords>

Whether the keyword generation support should be enabled.  This is a
boolean value and the default is false.

FIXME: Currently, support for keyword generation is configured into INN
semi-randomly (based on whether configure found the regex library); it
should be an option to configure and that option should be mentioned here.

=item I<keyartlimit>

Articles larger than this value in bytes will not have keywords generated
for them (since it would take too long to do so).  The default value is
C<100000> (approximately 100 KB).

=item I<keylimit>

Maximum number of bytes allocated for keyword data.  If there are more
keywords than will fit into this many bytes when separated by commas, the
rest are discarded.  The default value is C<512>.

=item I<keymaxwords>

Maximum number of keywords that will be generated for an article.  (The
keyword generation code will attempt to discard "noise" words, so the
number of keywords actually writen into the overview will usually be
smaller than this even if the maximum number of keywords is found.)  The
default value is C<250>.

=back

=head2 Posting

These parameters are only used by nnrpd(8), inews(1), and other programs
that accept or generate postings.  There are some special sets of settings
that are broken out separately after the initial alphabetized list.

=over 4

=item I<addnntppostingdate>

Whether to add an NNTP-Posting-Date: header to all local posts.  This is a
boolean value and the default is true.  Note that INN either does not add
this header or adds the name or IP address of the client.  There is no
intrinsic support for obfuscating the name of the client.  That has to be
done with a user-written Perl filter, if desired.

=item I<addnntppostinghost>

Whether to add an NNTP-Posting-Host: header to all local posts giving the
FQDN or IP address of the system from which the post was received.  This
is a boolean value and the default is true.

=item I<checkincludedtext>

Whether to check local postings for the ratio of new to quoted text and
reject them if that ratio is under 50%.  Included text is recognized by
looking for lines beginning with C<E<gt>>, C<|>, or C<:>.  This is a
boolean value and the default is false.

=item I<complaints>

The value of the X-Complaints-To: header added to all local posts.  The
default is the newsmaster's e-mail address.  (If the newsmaster, selected
at configure time and defaulting to C<usenet>, doesn't contain C<@>, the
address will consist of the newsmaster, a C<@>, and the value of
I<fromhost>.)

=item I<fromhost>

Contains a domain used to construct e-mail addresses.  The address of the
local news administrator will be given as <user>@I<fromhost>, where <user>
is the newsmaster user set at compile time (C<usenet> by default).  This
setting will also be used by mailpost(8) to fully qualify addresses and by
inews(1) to generate the Sender: header (and From: header if missing).
The value of the FROMHOST environment variable, if set, overrides this
setting.  The default is the fully-qualified domain name of the local
host.

=item I<localmaxartsize>

The maximum article size (in bytes) for locally posted articles.  Articles
larger than this will be rejected.  A value of C<0> allows any size of
article, but note that B<nnrpd> and B<innd> will crash if system memory is
exceeded.  See also I<maxartsize>, which applies to all articles including
those posted locally.  The default value is C<1000000> (approximately 1
MB).

=item I<moderatormailer>

The address to which to send submissions for moderated groups.  It is only
used if the F<moderators> file doesn't exist, or if the moderated group to
which an article is posted is not matched by any entry in that file, and
takes the same form as an entry in the F<moderators> file.  In most cases,
C<%s@moderators.isc.org> is a good value for this parameter (C<%s> is
expanded into a form of the newsgroup name).  See moderators(5) for more
details about the syntax.  The default is unset.  If this parameter isn't
set and an article is posted to a moderated group that does not have a
matching entry in the F<moderators> file, the posting will be rejected
with an error.

=item I<nnrpdauthsender>

Whether to generate a Sender: header based on reader authentication.  If
this parameter is set, a Sender: header will be added to local posts
containing the identity assigned by F<readers.conf>.  If the assigned
identity does not include an C<@>, the reader's hostname is used.  If this
parameter is set but no identity is be assigned, the Sender: header will
be removed from all posts even if the poster includes one.  This is a
boolean value and the default is false.

=item I<nnrpdposthost>

If set, nnrpd(8) and rnews(1) will pass all locally posted articles to the
specified host rather than trying to inject them locally.  See also
I<nnrpdpostport>.  This should always be set if I<xrefslave> is true.  The
default value is unset.

=item I<nnrpdpostport>

The port on the remote server to connect to to post when I<nnrpdposthost>
is used.  The default value is C<119>.

=item I<organization>

What to put in the Organization: header if it is left blank by the poster.
The value of the ORGANIZATION environment variable, if set, overrides this
setting.  The default is unset, which tells INN not to insert an
Organization: header.

=item I<spoolfirst>

If true, nnrpd(8) will spool new articles rather than attempting to send
them to innd(8).  If false, nnrpd will spool articles only if it receives
an error trying to send them to innd.  Setting this to true can be useful
if nnrpd must respond as fast as possible to the client; however, when
set, articles will not appear to readers until they are given to innd.
nnrpd won't do this; C<rnews -U> must be run periodically to take the
spooled articles and post them.  This is a boolean value and the default
is false.

=item I<strippostcc>

Whether to strip To:, Cc:, and Bcc: headers out of all local posts via
nnrpd(8).  The primary purpose of this setting is to prevent abuse of the
news server by posting to a moderated group and including To: or Cc:
headers in the post so that the news server will send the article to
arbitrary addresses.  INN now protects against this abuse in other ways
provided I<mta> is set to a command that includes C<%s> and honors it, so
this is generally no longer needed.  This is a boolean value and the
default is false.

=back

nnrpd(8) has support for controlling high-volume posters via an
exponential backoff algorithm, as configured by the following parameters.

Exponential posting backoff works as follows:  News clients are indexed by
IP address (or username, see I<backoffauth> below).  Each time a post is
received from an IP address, the time of posting is stored (along with the
previous sleep time, see below).  After a configurable number of posts in
a configurable period of time, nnrpd(8) will activate posting backoff and
begin to sleep for increasing periods of time before actually posting
anything.  Posts will still be accepted, but at an increasingly reduced
rate.

After backoff has been activated, the length of time to sleep is computed
based on the difference in time between the last posting and the current
posting.  If this difference is less than I<backoffpostfast>, the new
sleep time will be 1 + (previous sleep time * I<backoffk>).  If this
difference is less than I<backoffpostslow> but greater than
I<backoffpostfast>, then the new sleep time will equal the previous sleep
time.  If this difference is greater than I<backoffpostslow>, the new
sleep time is zero and posting backoff is deactivated for this poster.

Exponential posting backoff will not be enabled unless I<backoffdb> is set
and I<backoffpostfast> and I<backoffpostslow> are set to something other
than their default values.

Here are the parameters that control exponential posting backoff:

=over 4

=item I<backoffauth>

Whether to index posting backoffs by user rather than by source IP
address.  You must be using authentication in nnrpd(8) for a value of true
to have any meaning.  This is a boolean value and the default is false.

=item I<backoffdb>

The path to a directory, writeable by the news user, that will contain the
backoff database.  There is no default for this parameter; you must
provide a path to a creatable or writeable directory to enable exponential
backoff.

=item I<backoffk>

The amount to multiply the previous sleep time by if the user is still
posting too quickly.  A value of C<2> will double the sleep time for each
excessive post.  The default value is C<1>.

=item I<backoffpostfast>

Postings from the same identity that arrive in less than this amount of
time (in seconds) will trigger increasing sleep time in the backoff
algorithm.  The default value is C<0>.

=item I<backoffpostslow>

Postings from the same identity that arrive in greater than this amount of
time (in seconds) will reset the backoff algorithm.  Another way to look
at this constant is to realize that posters will be allowed to generate at
most 86400/I<backoffpostslow> posts per day.  The default value is C<1>.

=item I<backofftrigger>

This many postings are allowed before the backoff algorithm is triggered.
The default value is C<10000>.

=back

=head2 Monitoring

These parameters control the behavior of innwatch(8), the program that
monitors INN and informs the news administrator if anything goes wrong
with it.

=over 4

=item I<doinnwatch>

Whether to start innwatch(8) from rc.news.  This is a boolean value, and
the default is true.

=item I<innwatchbatchspace>

Free space in I<pathoutgoing>, in inndf(8) output units (normally
kilobytes), at which innd(8) will be throttled by innwatch(8), assuming a
default F<innwatch.ctl>.  The default value is C<800>.

=item I<innwatchlibspace>

Free space in I<pathdb>, in inndf(8) output units (normally kilobytes), at
which innd(8) will be throttled by innwatch(8), assuming a default
F<innwatch.ctl>.  The default value is C<25000>.

=item I<innwatchloload>

Load average times 100 at which innd(8) will be restarted by innwatch(8)
(undoing a previous pause or throttle), assuming a default
F<innwatch.ctl>.  The default value is C<1000> (that is, a load average of
10.00).

=item I<innwatchhiload>

Load average times 100 at which innd(8) will be throttled by innwatch(8),
assuming a default F<innwatch.ctl>.  The default value is C<2000> (that
is, a load average of 20.00).

=item I<innwatchpauseload>

Load average times 100 at which innd(8) will be paused by innwatch(8),
assuming a default F<innwatch.ctl>.  The default value is C<1500> (that
is, a load average of 15.00).

=item I<innwatchsleeptime>

How long (in seconds) innwatch(8) will sleep between each check of INN.
The default value is C<600>.

=item I<innwatchspoolnodes>

Free inodes in I<patharticles> at which innd(8) will be throttled by
innwatch(8), assuming a default F<innwatch.ctl>.  The default value is
C<200>.

=item I<innwatchspoolspace>

Free space in I<patharticles> and I<pathoverview>, in inndf(8) output
units (normally kilobytes), at which innd(8) will be throttled by
innwatch(8), assuming a default F<innwatch.ctl>.  The default value is
C<8000>.

=back

=head2 Logging

These parameters control what information INN logs.

=over 4

=item I<docnfsstat>

Whether to start cnfsstat(8) when innd(8) is started.  cnfsstat will log
the status of all CNFS cycbuffs to syslog on a periodic basis (frequency
is the default for C<cnfsstat -l>, currently 600 seconds).  This is a
boolean value and the default is false.

=item I<logartsize>

Whether the size of accepted articles (in bytes) should be written to the
article log file.  This is useful for flow rate statistics and is
recommended.  This is a boolean value and the default is true.

=item I<logcancelcomm>

Set this to true to log C<ctlinnd cancel> commands to syslog.  This is a
boolean value and the default is false.

=item I<logcycles>

How many old logs scanlogs(8) keeps.  scanlogs(8) is generally run by
news.daily(8) and will archive compressed copies of this many days worth
of old logs.  The default value is C<3>.

=item I<logipaddr>

Whether the verified name of the remote feeding host should be logged to
the article log for incoming articles rather than the last entry in the
Path: header.  The only reason to ever set this to false is due to some
interactions with F<newsfeeds> flags; see newsfeeds(5) for more
information.  This is a boolean value and the default is true.

=item I<logsitename>

Whether the names of the sites to which accepted articles will be sent
should be put into the article log file.  This is useful for debugging and
statistics and can be used by newsrequeue(8).  This is a boolean value and
the default is true.

=item I<nnrpdoverstats>

Whether nnrpd overview statistics should be logged via syslog.  This can
be useful for measuring overview performance.  This is a boolean value and
the default is false.

=item I<nntpactsync>

How many articles to process on an incoming channel before logging the
activity.  The default value is C<200>.

FIXME: This is a rather unintuitive name for this parameter.

=item I<nntplinklog>

Whether to put the storage API token for accepted articles (used by
nntplink) in the article log.  This is a boolean value and the default is
false.

=item I<stathist>

Where to write history statistics for analysis with
F<contrib/stathist.pl>; this can be modified with ctlinnd(8) while innd is
running.  Logging does not occur unless a path is given, and there is no
default value.

=item I<status>

How frequently (in seconds) innd(8) should write out a status report.  The
report is written to I<pathhttp>/inn_status.html.  If this is set to C<0> or
C<false>, status reporting is disabled.  The default value is C<0>.

=item I<timer>

How frequently (in seconds) innd(8) should report performance timings to
syslog.  If this is set to C<0>, performance timing is disabled.  Enabling
this is highly recommended, and innreport(8) can produce a nice summary of
the timings.  If set to C<0>, performance timings in nnrpd(8) are also
disabled, although nnrpd always reports statistics on exit and therefore
any non-zero value is equivalent for it.  The default value is C<0>.

=back

=head2 System Tuning

The following parameters can be modified to tune the low-level operation
of INN.  In general, you shouldn't need to modify any of them except
possibly I<rlimitnofile> unless the server is having difficulty.

=over 4

=item I<badiocount>

How many read or write failures until a channel is put to sleep or
closed.  The default value is C<5>.

=item I<blockbackoff>

Each time an attempted write returns EAGAIN or EWOULDBLOCK, innd(8) will
wait for an increasing number of seconds before trying it again.  This is
the multiplier for the sleep time.  If you're having trouble with channel
feeds not keeping up, it may be good to change this value to C<2> or C<3>,
since then when the channel fills INN will try again in a couple of
seconds rather than waiting two minutes.  The default value is C<120>.

=item I<chaninacttime>

The time (in seconds) to wait between noticing inactive channels.  The
default value is C<600>.

=item I<chanretrytime>

How many seconds to wait before a channel restarts.  The default value is
C<300>.

=item I<datamovethreshold>

The threshold for deciding whether to move already-read data to the top of
buffer or extend the buffer.  The buffer described here is used for reading
NNTP data.  Increasing this value may improve performance, but it should
not be increased on Systems with insufficient memory.  Permitted values
are between C<0> and C<1048576> (out of range values are treated as
C<1048576>) and the default value is C<8192>.  

=item I<icdsynccount>

How many article writes between updating the active and history files.
The default value is C<10>.

=item I<keepmmappedthreshold>

When using buffindexed, retrieving overview data (that is, responding to
XOVER or running expireover) causes mmapping of all overview data blocks
which include requested overview data for newsgroup.  But for high volume
newsgroups like control.cancel, this may cause too much mmapping at once
leading to system resource problems.  To avoid this, if the amount to be
mmapped exceeds I<keepmmappedthreshold> (in KB), buffindexed mmap's just
one overview block (8 KB).  This parameter is specific to buffindexed
overview storage method.  The default value is C<1024> (1 MB).

=item I<maxcmdreadsize>

If set to anything other than C<0>, maximum buffer size (in bytes) for
reading NNTP command will have this value.  It should not be large on
systems which are slow to process and store articles, as that would lead
to innd(8) spending a long time on each channel and keeping other channels
waiting.  The default value is BUFSIZ defined in stdio.h (C<1024> in most
environments, see setbuf(3)).

=item I<maxforks>

How many times to attempt a fork(2) before giving up.  The default value
is C<10>.

=item I<nicekids>

If set to anything other than C<0>, all child processes of innd(8) will
have this nice(2) value.  This is usually used to give all child processes
of innd(8) a lower priority (higher nice value) so that innd(8) can get
the lion's share of the CPU when it needs it.  The default value is C<4>.

=item I<nicenewnews>

If set to anything greater than C<0>, all nnrpd(8) processes that receive
and process a NEWNEWS command will nice(2) themselves to this value
(giving other nnrpd processes a higher priority).  The default value is
C<0>.  Note that this value will be ignored if set to a lower value than
I<nicennrpd> (or I<nicekids> if nnrpd(8) is spawned from innd(8)).

=item I<nicennrpd>

If set to anything greater than C<0>, all nnrpd(8) processes will nice(1)
themselves to this value.  This gives other news processes a higher
priority and can help overchan(8) keep up with incoming news (if that's
the object, be sure overchan(8) isn't also set to a lower priority via
I<nicekids>).  The default value is C<0>, which will cause nnrpd(8)
processes spawned from innd(8) to use the value of I<nicekids>, while
nnrpd(8) run as a daemon will use the system default priority.  Note that
for nnrpd(8) processes spawned from innd(8), this value will be ignored if
set to a value lower than I<nicekids>.

=item I<pauseretrytime>

Wait for this many seconds before noticing inactive channels.
Wait for this many seconds before innd processes articles when it's paused
or the number of channel write failures exceeds I<badiocount>.  The
default value is C<300>.

=item I<peertimeout>

How long (in seconds) an innd(8) incoming channel may be inactive before
innd closes it.  The default value is C<3600> (an hour).

=item I<rlimitnofile>

The maximum number of file descriptors that innd(8) or innfeed(8) can have
open at once.  If innd(8) or innfeed(8) attempts to open more file
descriptors than this value, it is possible the program may throttle or
otherwise suffer reduced functionality.  The number of open file
descriptors is roughly the maximum number of incoming feeds and outgoing
batches for innd(8) and the number of outgoing streams for innfeed(8).  If
this parameter is set to a negative value, the default limit of the
operating system will be used; this will normally be adequate on systems
other than Solaris.  Nearly all operating systems have some hard maximum
limit beyond which this value cannot be raised, usually either 128, 256,
or 1024.  The default value of this parameter is C<-1>.  Setting it to
C<256> on Solaris systems is highly recommended.

=back

=head2 Paths and File Names

=over 4

=item I<patharchive>

Where to store archived news.  The default value is I<pathspool>/archive.

=item I<patharticles>

The path to where the news articles are stored (for storage methods other
than CNFS).  The default value is I<pathspool>/articles.

=item I<pathbin>

The path to the news binaries.  The default value is I<pathnews>/bin.

=item I<pathcontrol>

The path to the files that handle control messages.  The code for handling
each separate type of control message is located here.  Be very careful
what you put in this directory with a name ending in C<.pl>, as it can
potentially be a severe security risk.  The default value is
I<pathbin>/control.

=item I<pathdb>

The path to the database files used and updated by the server (currently,
F<active>, F<active.times>, F<history> and its indices, and
F<newsgroups>).  The default value is I<pathnews>/db.

=item I<pathetc>

The path to the news configuration files.  The default value is
I<pathnews>/etc.

=item I<pathfilter>

The path to the Perl, Tcl, and Python filters.  The default value is
I<pathbin>/filter.

=item I<pathhttp>

Where any HTML files (such as periodic status reports) are placed.  If the
news reports should be available in real-time on the web, the files in
this directory should be served by a web server.  The default value is
the value of I<pathlog>.

=item I<pathincoming>

Location where incoming batched news is stored.  The default value is
I<pathspool>/incoming.

=item I<pathlog>

Where the news log files are written.  The default value is
I<pathnews>/log.

=item I<pathnews>

The home directory of the news user and usually the root of the news
hierarchy.  There is no default; this parameter must be set in F<inn.conf>
or INN will refuse to start.

=item I<pathoutgoing>

Default location for outgoing feed files.  The default value is
I<pathspool>/outgoing.

=item I<pathoverview>

The path to news overview files.  The default value is
I<pathspool>/overview.

=item I<pathrun>

The path to files required while the server is running and run-time state
information.  This includes lock files and the sockets for communicating
with innd(8).  This directory and the control sockets in it should be
protected from unprivileged users other than the news user.  The default
value is I<pathnews>/run.

=item I<pathspool>

The root of the news spool hierarchy.  This used mostly to set the
defaults for other parameters, and to determine the path to the backlog
directory for innfeed(8).  The default value is I<pathnews>/spool.

=item I<pathtmp>

Where INN puts temporary files.  For security reasons, this is not the
same as the system temporary files directory (INN creates a lot of
temporary files with predictable names and does not go to particularly
great lengths to protect against symlink attacks and the like; this
is safe provided that normal users can't write into its temporary
directory).  The default value is set at configure time and defaults to
I<pathnews>/tmp.

=back

=head1 EXAMPLE

Here is a very minimalist example that only sets those parameters that are
required.

    mta:                /usr/lib/sendmail -oi -oem %s
    ovmethod:           tradindexed
    pathhost:           news.example.com
    pathnews:           /usr/local/news
    hismethod:          hisv6

For a more comprehensive example, see the sample F<inn.conf> distributed
with INN and installed as a starting point; it contains all of the default
values for reference.

=head1 HISTORY

Written by Rich $alz <rsalz@uunet.uu.net> for InterNetNews and since
modified, updated, and reorganized by innumerable other people.

$Id: inn.conf.pod 7751 2008-04-06 14:35:40Z iulius $

=head1 SEE ALSO

inews(1), innd(8), innwatch(8), nnrpd(8), rnews(1).

Nearly every program in INN uses this file to one degree or another.  The
above are just the major and most frequently mentioned ones.