.\" Hey, Emacs! This is an -*- nroff -*- source file.
-.TH CHIARK\-NAMED\-CONF 8 "30th December 2001" "Greenend" "chiark utilities"
+.TH CHIARK\-NAMED\-CONF 8 "12th January 2002" "Greenend" "chiark utilities"
.SH NAME
chiark\-named\-conf \- check and generate nameserver configuration
-
.SH SYNOPSIS
-.B chiark\-named\-conf [\fIoptions\fP] \-n|\-y|\-f
+.BR chiark\-named\-conf " [\fIoptions\fP] " \-n | \-y | \-f
.br
-.B chiark\-named\-conf [\fIoptions\fP] \fIzone ...\fP
-
+\fBchiark\-named\-conf\fP [\fIoptions\fP] \fIzone ...\fP
.SH DESCRIPTION
.B chiark\-named\-conf
is a tool for managing nameserver configurations and checking for
suspected DNS problems. Its main functions are to check that
-delegations are appropriate and working, and to generate a
-configuration for
+delegations are appropriate and working, that secondary zones are
+slaved from the right places, and to generate a configuration for
.BR BIND ,
from its own input file.
+By default, for each zone, in addition to any warnings, the output
+lists the zone's configuration type. If the zone is checked, the
+serial number at each of the nameservers is shown, with any
+unpublished primary having
+.B *
+after the serial number.
.SH OPTIONS
+
.SS MODE OPTIONS
If one of the options
.BR -n ", " -y ", or " -f
Generate and install new nameserver config, without doing any
configuration cross-checking. (Syntax errors in our input
configuration will still abort this operation.)
+.TP
+.BR \-\-nothing
+Do nothing: do no checks, and don't write a new config. This can be
+used to get a list of the zones being processed.
+.TP
+.BR \-\-mail\-first " | " \-\-mail\-middle " | " \-\-mail\-final
+Send mails to zone SOA MNAMEs reporting zones with problems. You must
+call chiark\-named\-conf at least twice, once with \-\-mail\-first,
+and later with \-\-mail\-final, and preferably with one or more calls
+to \-\-mail\-middle in between. All three options carry out a check
+and store the results; \-\-mail\-final also sends a mail to the zone
+SOA MNAME or local administrator, if too many of the calls had errors
+or warnings (calls before the most recent \-\-mail\-first being
+ignored).
+.TP
+.B \-mail\-final\-test
+just like \-\-mail\-final except that it always sends mail to the
+local server admin and never to remote zone contacts, adding
+.B (testing!)
+to the start of the To: field.
.LP
Alternatively, one or more zone names may be supplied as arguments, in
which case their delegations will be checked, and compared with the
.SS ADDITIONAL OPTIONS
.TP
-\fB\-C\fP|\-\-config \fIconfig\-file\fP
+.BR \-A | \-\-all
+Checks even zones known to be broken. Ie, ignores the
+.B ?
+zone style modifier in the configuration.
+.TP
+.BR \-C | \-\-config " \fIconfig\-file\fP"
Use
.I config\-file
instead of
.BR /etc/bind/chiark-conf-gen.zones .
+Also changes the default directory.
+.TP
+.BR \-D
+Enables debugging. Useful for debugging chiark\-named\-conf, but
+probably not useful for debugging your DNS configuration. Repeat to
+increase the debugging level. (Maximum is
+.BR -DD .)
+.TP
+.BR \-g | \-\-glueless
+Do not warn about glueless referrals (strictly, makes the zone style
+modifier
+.B ~
+the default). Not recommended - see the section GLUELESSNESS, below.
+.TP
+.BR \-l | \-\-local
+Only checks for mistakes which are the responsibility of the local
+administrator (to fix or get fixed). This means that for published
+and stealth zones we only check that we're slaving from the right
+place and that any names and addresses for ourself are right. For
+primary zones all checks are still done. It is a mistake to specify
+.B \-l
+with foreign zones (zones supplied explictly on the command line but
+not relevant to the local server); doing so produces a warning.
+.TP
+.BI \-m group !*$@~?
+Overrides a
+.B modifiers
+directive in the configuration file. The modifiers specified in the
+directive are completely replaced by those specified in this command
+line option. (Note that modifiers specified in per-zone directives
+still override these per-group settings.) If more than one
+.B modifiers
+directive specifies the same group, they are all affected.
+.B modifiers
+directives which don't specify a group cannot be affected. It is an
+error if the group does not appear in the config file. See ZONE STYLE
+MODIFIERS, below.
+.PP
+The special group
+.B foreign
+is used for zones which don't appear in the configuration file.
.TP
.BR \-q | \-\-quiet
-Do not print any information about zone(s) which do not have warnings.
+Suppress the usual report of the list of nameservers for each zone and
+the serial number from each. When specified twice, do not print any
+information except warnings.
.TP
-.BR \-v | \-\-verbose
-Print additional information about each zone.
+.BR \-r | \-\-repeat
+When a problem is detected, warn for all sources of the same imperfect
+data, rather than only the first we come across
.TP
-.BR \-D
-Enables debugging. Useful for debugging chiark\-named\-conf, but
-probably not useful for debugging your DNS configuration.
-.SH CONFIGURATION
+.BR \-v | \-\-verbose
+Print additional information about what is being checked, as we go
+along.
+.SH USAGE
The file
.B /etc/bind/chiark-conf-gen.zones
(or other file specified with the
are permitted. Leading and trailing whitespace on each line is
ignored. Comments are lines starting with
.BR # .
+Ending a line with a
+.BR \\
+joins it to the next line, so that long directives can be split across
+several physical lines.
.SS GENERAL DIRECTIVES
These directives specify general configuration details. They should
appear before directives specifying zones, as each will affect only
later zone directives.
.TP
-\fBself\-ns\fP \fIfqdn ...\fP
-Specifies the list of names that this server may be known by in NS
-records. There is no default.
-.TP
-\fBself\-soa\fP \fIfqdn ...\fP
-Specifies the list of names that this server may be known by in
-the ORIGIN field of SOA records. There is no default.
-.TP
-\fBself\fP \fIfqdn ...\fP
-Equivalent to both
-.BR self\-ns " and " self-\soa
-with the same set of names.
-.TP
-\fBslave\-dir\fP \fIdirectory\fP [[\fIprefix\fP] \fIsuffix\fP]
-Specifies the directory in which slave (secondary and stealth)
-zonefiles should be placed. The default
-.I directory
-is
-.BR /var/cache/bind/chiark-slave .
-The default
-.IR suffix " and " prefix
-are empty; they also will be reset to these defaults by a
-.B slave\-dir
-directive which does not specify them.
+\fBadmin\fP \fIemail\-address\fP
+Specifies the email address of the local administrator. This is used
+in the From: line of mails sent out, and will also receive copies of
+the reports. There is no default.
.TP
\fBdefault\-dir\fP \fIdirectory\fP
Makes
.B -C
option is specified.
.TP
+\fBforbid\-addr\fP [\fIip-address ...\fP]
+Specifies the list of addresses that are forbidden as any nameserver
+for any zone. The default is no such addresses.
+.TP
+\fBserverless\-glueless\fP \fIdomain ...\fP
+Specifies a list of domains under which we do not expect to find any
+nameservers; for these zones it is OK to find glueless referrals.
+Each domain listed names a complete subtree of the DNS, starting at
+the named point. The default is
+.BR "in\-addr.arpa ip6.arpa ip6.int" .
+
+To avoid indefinitely long or even circularly glueless referrals
+(which delay or prevent lookups) it is necessary for all sites to
+effectively implement similar conventions; currently the author
+believes that only the reverse lookup namespaces are conventionally
+devoid of nameservers, and therefore fine to provide glueless
+referrals for. See GLUELESSNESS below.
+.TP
+\fBmail\-state\-dir\fP \fIdirectory\fP
+Uses
+.I directory
+for storing information about recent failures for mailing to zone
+admins. See \-\-mail\-first et al. Old files in here should be
+cleaned up periodically out of cron. There is no default.
+.TP
+\fBmail\-max\-warnfreq\fP \fIpercentage\fP
+When \-\-mail\-final is used, a mail will be sent to all zones which
+had warnings or errors more than
+.IR percentage %
+of the times \-\-mail\-* was used (since the last \-\-mail\-first).
+The default is 50%.
+.TP
+.BR modifiers " " !*$@~? "] [\fIgroup\fP]"
+Applies the specified zone style modifiers (see below) to subsequently
+declared zones (until the next
+.B modifiers
+directive), as if the modifiers specified were written out for
+each zone. You must specify at least one character for the modifiers;
+if you want to reset everything to the default, just say
+.BR ! .
+If style modifiers specified in the zone directive
+conflict with the
+.B modifiers
+directive, those specified in the zone directive take effect.
+.I group
+may contain alphanumerics and underscores, and is used for the
+.B -m
+command-line option.
+.TP
+\fBself\-addr\fP \fIip-address ...\fP
+Specifies the list of addresses that this server may be known by in
+A records. There is no default.
+.TP
\fBoutput\fP \fIformat\fP \fIfilename\fP [\fIformat\fP \fIfilename ...\fP]
Arranges that each
.I filename
configuration before the first
.B output
directive.
+.TP
+\fBself\-ns\fP \fIfqdn ...\fP
+Specifies the list of names that this server may be known by in NS
+records. There is no default. Any trailing * is replaced by the name
+of the zone being checked, so for example
+.B self\-ns isp.ns.*
+before the zone example.com would mean to expect us to be listed as
+isp.ns.example.com
+in the NS RRset.
+.TP
+\fBself\-soa\fP \fIfqdn ...\fP
+Specifies the list of names that this server may be known by in
+the ORIGIN field of SOA records. There is no default. Any trailing
+* is replaced by the name of the zone, as for
+.BR self\-ns .
+.TP
+.BI self " fqdn ..."
+Equivalent to both
+.B self\-ns " and " self\-soa
+with the same set of names.
+.TP
+\fBslave\-dir\fP \fIdirectory\fP [[\fIprefix\fP] \fIsuffix\fP]
+Specifies the directory in which slave (published and stealth)
+zonefiles should be placed. The default
+.I directory
+is
+.BR /var/cache/bind/chiark-slave .
+The default
+.IR suffix " and " prefix
+are empty; they also will be reset to these defaults by a
+.B slave\-dir
+directive which does not specify them.
.SS ZONE DIRECTIVES
These directives specify one or more zones.
.TP
-\fBprimary\fP \fIzone\fP \fIfilename\fP
+.BR primary [ !*$@~? "] \fIzone filename\fP"
Specifies that this server is supposed to be the primary nameserver
for
.I zone
and that the zone data is to be found in
.IR filename .
.TP
-\fBprimary-dir\fP \fIdirectory\fP [[\fIprefix\fP] \fIsuffix\fP]
+.BR primary\-dir [ !*$@~? "] \fIdirectory\fP[" / "\fIprefix\fP] [\fIsuffix\fP[" / \fIsubfile\fP]]
Search
.I directory
-for files whose names match the glob pattern
-.IR suffix * prefix .
-Each such file is taken to represent a zone file for which this server
-is supposed to be the primary. * is the name of the zone. The
-default for
-.I suffix
-is
-.BR _db ;
-the default for
+for files whose names start with
.I prefix
-is empty.
+and end with
+.IR suffix .
+Each such file is taken to represent a zone file for which this server
+is supposed to be the primary; the part of the filename between
+.IR prefix " and " suffix
+is the name of the zone.
+
+If
+.BI / subfile
+is specified, then instead of looking for files, we search for
+directories containing
+.IR subfile ;
+directories which do not contain the subfile are simply skipped.
+
+If
+.IR directory [\fB/\fP prefix ]
+exists as specified and is a directory then it is interpreted as
+.I directory
+with an empty prefix; otherwise the final path component is assumed to
+be the prefix. If no
+.IB suffix / subfile
+is specified then the default is
+.BR _db .
.TP
-\fBsecondary\fP \fIzone\fP \fIorigin\-addr\fP
-Specifies that this server is supposed to be a published secondary for
-the zone in question.
+.BR published [ !*$@~? "] \fIzone origin\-addr\fP"
+Specifies that this server is supposed to be a published slave
+nameserver for the zone in question.
.TP
-\fBstealth\fP \fIzone\fP \fIserver\-addr ...\fP
+.BR stealth [ !*$@~? "] \fIzone server\-addr ...\fP"
Specifies that this server is supposed to be an unpublished secondary
(aka stealth secondary) for the zone in question.
+.SS ZONE STYLE MODIFIERS
+Each of the zone directives may optionally be followed by one or more
+of the following characters (each at most once):
+.TP
+.B !
+Reverses the meaning of all style modifiers after the
+.BR ! .
+Only one
+.BR !
+must appear in the modifier list. In this list, other modifiers which
+default to `enabled' are described by describing the effect of their
+inverse - see the description for
+.B !@
+below.
+.TP
+.B *
+Indicates that the zone is unofficial, ie that it is not delegated as
+part of the global Internet DNS and that no attempt should be made to
+find the superzone and check delegations. Note that unofficial, local
+zones should be created with caution. They should be in parts of the
+namespace which are reserved for private use, or belong to the actual
+zone maintainer.
+.TP
+.B $
+Indicates that any mails should be sent about the zone to the
+nameserver admin rather than to the zone SOA MNAME. This is the
+default unless we are supposedly a published server for the zone.
+.TP
+.B !@
+Indicates that no mails should be sent about the zone to anyone.
+.TP
+.B ~
+Indicates that the zone's delegation is known to be glueless, and that
+lack of glue should not be flagged. Not recommended - see the section
+GLUELESSNESS, below.
+.TP
+.B ?
+Indicates that the zone is known to be broken and no checks should be
+carried out on it, unless the
+.B \-A
+option is specified.
.SS OTHER DIRECTIVES
.TP
\fBinclude\fP \fIfile\fP
Origin server's data: The set of nameservers in the origin server's
version of the zone should be a superset of those in the delegations.
-Our zone configuration: For
-.B primary
-zones, the SOA origin should be one of the names specified with
-.BR self\-soa " (or " self ). For
-.B secondary
-zones, the address should be that of the SOA origin. For
-.B stealth
-zones, the address should be that of the SOA origin or one of the
-published nameservers.
+Our zone configuration: For primary zones, the SOA origin should be
+one of the names specified with
+.BR self\-soa " (or " self ).
+For published zones, the address should be that of the SOA origin.
+For stealth zones, the address should be that of the SOA origin or one
+of the published nameservers.
+.SH GLUELESSNESS
+Glue is the name given for the addresses of nameservers which are
+often supplied in a referral. In fact, it turns out that it is
+important for the reliability and performance of the DNS that
+referrals, in general, always come with glue.
+
+Firstly, glueless referrals usually cause extra delays looking up
+names. BIND 8, when it receives a completely glueless referral and
+does not have the nameservers' addresses in its cache, will start
+queries for the nameserver addresses; but it will throw the original
+client's question away, so that when these queries arrive, it won't
+restart the query from where it left off. This means that the client
+won't get its answer until it retries, typically at least 1 second
+later - longer if you have more than one nameserver listed. Worse, if
+the nameserver to which the glueless referral points is itself under
+another glueless referral, another retry will be required.
+
+Even for better resolvers than BIND 8, long chains of glueless
+referrals can cause performance and reliability problems, turning a
+simple two or three query exchange into something needing more than a
+dozen queries.
+
+Even worse, one might accidentally create a set of circularly glueless
+referrals such as
+.br
+.B example.com NS ns0.example.net.uk
+.br
+.B example.com NS ns1.example.net.uk
+.br
+.B example.net.uk NS ns0.example.com
+.br
+.B example.net.uk NS ns1.example.com
+.br
+Here it is impossible to look up anything in either example.com or
+example.net.uk.
+
+There are, as far as the author is aware, no generally agreed
+conventions or standards for avoiding unreasonably long glueless
+chains, or even circular glueless situations. The only way to
+guarantee that things will work properly is therefore to always supply
+glue.
+
+However, the situation is further complicated by the fact that many
+implementations (including BIND 8.2.3, and many registry systems),
+will refuse to accept glue RRs for delegations in a parent zonefile
+unless they are under the parent's zone apex. In these cases it can
+be necessary to create names for the child's nameservers which are
+underneath the child's apex, so that the glue records are both in the
+parent's bailiwick and obviously necessary.
+
+In the past, the `shared registry system' managing .com, .net and .org
+did not allow a single IPv4 address to be used for more than one
+nameserver name. However, at the time of writing (October 2002) this
+problem seems to have been fixed, and the workaround I previously
+recommended (creating a single name for your nameserver somewhere
+in .com, .net or .org, and using that for all the delegations
+from .com, .net and .org) should now be avoided.
+
+Finally, a note about `reverse' zones, such as those in in-addr.arpa:
+It does not seem at all common practice to create nameservers in
+in-addr.arpa zones (ie, no NS RRs seem to point into in-addr.arpa,
+even those for in-addr.arpa zones). Current practice seems to be to
+always use nameservers for in-addr.arpa which are in the normal,
+forward, address space. If everyone sticks to the rule of always
+publishing nameservers names in the `main' part of the namespace, and
+publishing glue for them, there is no chance of anything longer than a
+1-step glueless chain might occur for a in-addr.arpa zone. It is
+probably best to maintain this as the status quo, despite the
+performance problem this implies for BIND 8 caches. This is what the
+serverless\-glueless directive is for.
+
+Dan Bernstein has some information and examples about this at
+.UR http://cr.yp.to/djbdns/notes.html#gluelessness
+http://cr.yp.to/djbdns/notes.html#gluelessness
+.UE
+but be warned that it is rather opinionated.
+.SS GLUELESSNESS SUMMARY
+
+I recommend that every nameserver should have its own name in every
+forward zone that it serves. For example:
+.br
+.B zone.example.com NS servus.ns.example.com
+.br
+.B servus.ns.example.com A 127.0.0.2
+.br
+.B 2.0.0.127.in-addr.arpa PTR servus.example.net
+.br
+.B servus.example.net A 127.0.0.2
+.LP
+Domain names in
+.B in-addr.arpa
+should not be used in the right hand side of NS records.
+.SH SECURITY
+chiark\-named\-conf is supposed to be resistant to malicious data in
+the DNS. It is not resistant to malicious data in its own options,
+configuration file or environment. It is not supposed to read its
+stdin, but is not guaranteed to be safe if stdin is dangerous.
+.LP
+Killing chiark-named-conf suddenly should be safe, even with
+.BR -y " or " -f
+(though of course it may not complete its task if killed), provided
+that only one invocation is made at once.
+.LP
+Slow remote nameservers will cause chiark-named-conf to take
+excessively long.
+.SH EXIT STATUS
+.TP
+.B 0
+All went well and there were no warnings.
+.TP
+any other
+There were warnings or errors.
.SH FILES
.TP
.B /etc/bind/chiark-conf-gen.zones
.TP
.B /var/cache/bind/chiark-slave
Default location for slave zones.
+.SH ENVIRONMENT
+.LP
+Setting variables used by
+.BR dig (1)
+and
+.BR adnshost (1)
+will affect the operation of chiark\-named\-conf.
+Avoid messing with these if possible.
+.LP
+.B PATH
+is used to find subprograms such as
+.BR dig " and " adnshost .
+.SH BUGS
+The determination of the parent zone for each zone to be checked, and
+its nameservers, is done simply using the system default nameserver.
+
+The processing of output from
+.B dig
+is not very reliable or robust, but this is mainly the fault of dig.
+This can lead to somewhat unhelpful error reporting for lookup
+failures.
.SH AUTHOR
.B chiark\-named\-conf
-and this manpage were written by Ian Jackson <ian@chiark.greenend.org.uk>.
+and this manpage were written by Ian Jackson
+<ian@chiark.greenend.org.uk>. They are Copyright 2002 Ian Jackson.
+
+chiark\-named\-conf and this manpage are free software; you can
+redistribute it and/or modify it under the terms of the GNU General
+Public License as published by the Free Software Foundation; either
+version 2, or (at your option) any later version.
+
+This is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+details.
+
+You should have received a copy of the GNU General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
~ian / chiark-utils.git / blobdiff