- Domain Name Server Configuration Utilities -- NSC 3.0
+ Domain Name Server Configuration Utilities -- NSC 5.0
- (c) 1997--2003 Martin Mares <mj@ucw.cz>
+ (c) 1997--2019 Martin Mares <mj@ucw.cz>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+-----------------------------------------------------------------------
+WARNING: There were several incompatible changes between major versions
+ See NEWS for the summary of changes.
+-----------------------------------------------------------------------
+
+
NSC is a set of shell and M4 scripts for easy maintenance of DNS zone files
-and name server daemon configuration (currently available only for BIND 8.X,
+and name server daemon configuration (currently available only for BIND 8.x/9.x,
but easily portable for other daemons). It has been designed to make administration
of a DNS server a piece of cake (unlike other utilities which resemble more
an English pudding :-) ), which includes automatic generation of reverse records
for all your hosts, handling of classless reverse delegations and support for IPv6
-(AAAA and PTR in in6.arpa, not A6 and DNAME which seem to be dying out).
+(AAAA and PTR in ip6.arpa, not A6 and DNAME which seem to be dying out).
- NSC requires GNU m4 and a POSIX-compatible shell, some of the extra utilities
-require Perl 5. I've tested everything on Linux (Debian Woody), but the whole
-package should run on other unices as well.
+ NSC requires GNU m4, GNU Bash, the `md5sum' and `sha1sum' utilities (which
+are present for example in GNU coreutils), and utilities distributed with BIND.
+Some of the extra utilities require Perl 5. I've tested everything on Linux
+(Debian Stretch), but the whole package should run on other unices as well.
The whole package can be used and distributed according to the terms of the
-GNU General Public License. See file COPYING in any of the GNU utility archives
-(you should have one as you are expected to have at least GNU M4 ;-)).
+GNU General Public License, version 2 or higher. See file COPYING in any of the
+GNU utility archives (you should have one as you are expected to have at least
+GNU M4 ;-)).
-1. Quick Howto for the Impatient
+0. Quick Howto for the Impatient
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
(everything will be explained in more detail in the subsequent sections)
- Create a directory where all NSC files will reside (e.g., /etc/named)
and copy everything from the NSC distribution here.
- - Symlink /etc/bind/named.conf (or /etc/named.conf or where the config file
- of your installation of BIND resides) to /etc/named/named.conf
+ - Add an include directive to your BIND configuration file (usually
+ /etc/bind/named.conf), referring to /etc/named/named.conf.
- Change directory to /etc/named
- Create cf/<domain-name> for all domains (again, you can easily follow
the example domains).
+ - If you are using BIND 9.x, make the `bak' directory writable
+ by the bind user.
+
- Run bin/nsconfig (Makefile and named.conf will be generated).
- Run make.
- Enjoy your new DNS setup. If everything goes OK, be happy. Else
write a bug report :-)
- - Every time you modify the domain files
+ - Every time you modify the domain files, re-run make. If you have
+ added or removed domains or changed options which affect named.conf,
+ re-run bin/nsconfig before make.
- An interesting companion to this package is the DNS Sleuth -- a DNS zone
+An interesting companion to this package is the DNS Sleuth -- a DNS zone
consistency checker. It's a simple utility written in Perl with help of the
DNS module and it should be able to detect all common errors in DNS setup
(I have written it after much disappointment with the other checkers).
-The Sleuth is available online on http://atrey.karlin.mff.cuni.cz/~mj/sleuth/,
-follow the links to download the source.
+The Sleuth is available from http://mj.ucw.cz/sw/sleuth/. However, I haven't
+updated Sleuth for a long time, so it does not know about DNSSEC yet.
-2. Directory structure
+1. Directory structure
~~~~~~~~~~~~~~~~~~~~~~
The NSC directory (/etc/named in the above example) contains the following
files and subdirectories:
cf/ - user-defined configuration files
- cf/domains - the domain list (see Section 3)
- cf/config - global settings (see Section XXX)
+ cf/domains - the domain list (see Section 2)
+ cf/config - global settings (see Section 3)
cf/<domain> - each domain has its own config file
bin/ - commands (e.g., nsconfig)
m4/ - M4 scripts (used by the commands)
bak/ - backups of zones we serve as a secondary NS for
ver/ - version files where NSC remembers version
numbers of the primary zones
+ tmp/ - temporary files
+ hash/ - hashes of zone files used for detection of changes
+ dss/<domain> - DNSSEC DS records
+ keys/<domain>/ - DNSSEC keys
+ khash/ - hashes of DNSSEC keys used for detection of changes
How are different files created:
- You create everything in cf/.
- Then you run bin/nsconfig.
+ - If you want to use DNSSEC, create keys (see section 8)
- Makefile and named.conf gets created according to cf/domains.
- You run make.
- The Makefile creates primary zone files in zone/ and version files
~~~~~~~~~~~~~~~~~~~~~~~
The domain list contains configuration commands describing all domains handled
by your server and their parameters. In fact, it's a M4 script, but viewing it as
-a config file is a good approximation (however, see Section XXX for some caveats).
+a config file is a good approximation (however, see Section 8 for some caveats).
Lines starting with a semicolon are treated as comments and ignored. Text outside
declarations is silently ignored.
concatenated to produce a single configuration). See the next
section for a look inside these files.
+ When the zone name contains a slash (as happens in classless
+ reverse zones), it is replaced by "@" in the cf file name.
+
SECONDARY(zone, primary)
Define a zone we run a secondary name server for.
"primary" is an IP address of the primary name server.
You can also use the REV macro explicitly, which can be handy
for example in SECONDARY declarations.
-CONFIG(...) - insert user data to named.conf
+FORWARDED(zone, ip...)
+ Define a forwarding zone. All queries are forwarded to the
+ specified name servers.
+
+BLACKHOLE(zone)
+ Define an empty zone according to RFC 6303. This is usually done
+ for zones for which clients are known to erroneously ask queries
+ (e.g., reverse resolving of link-local addresses). The contents
+ served for these zones is taken from cf/blackhole.
+
+ZONE_OPTIONS(`options;
+ more options;
+')
+ Define options to be inserted to all subsequent zone declarations
+ until the next ZONE_OPTIONS command. Please keep in mind that the
+ semicolon character act as M4 comment, so you need to put the
+ closing quote at a separate line. See our example cf/domains.
+
+CONFIG(...)
+ Insert user data to named.conf, again beware of semicolons.
-MAKEFILE(...) - insert user data to Makefile
+MAKEFILE(...)
+ Insert user data to Makefile.
+
+DNSSEC(`declarations...')
+ Request DNSSEC signing for all zones declared within the block.
+
+DSFOR(zone)
+ Declare dependency of the previous PRIMARY/REVERSE domain on DS
+ records for the given zone configured in dss/*.
3. The Domain Files
declarations is copied to the zone file as well, so you can spice up the NSC
output with your own records.
+All host or domain names are either names relative to the current domain
+with no dots inside or absolute names (in this case, NSC automatically
+ensures that the trailing dot is present in the resource records). Relative
+names with dots are not supported, but they are rare and you can always write
+them as absolute anyway.
+
Your menu:
SOA(domain-name)
day (in which case NSC stops and tells you to tweak the serial
number manually).
- The SOA record otherwise acts like a subdomain (D) declaration,
+ The SOA record otherwise acts like a sub-domain (D) declaration,
therefore it can be followed by other records like NS (mandatory)
or MX.
ADDR(addr...)
Specify addresses for the current host. In the normal mode, it
- creates A records, in the reverse mode, PTR records.
+ creates A/AAAA records, in the reverse mode, PTR records.
H(host, addr...)
A shortcut for H(host) ADDR(addr...) -- in many cases everything
you need for a single host.
DADDR(addr...)
- Like ADDR, but supresses PTR records. (This one is useful if you
+ Like ADDR, but suppresses PTR records. (This one is useful if you
have a single IP address used for zillions of names and you want
to avoid having zillions of PTR records for the same address.)
A shortcut for H(host) DADDR(addr...)
D(domain)
- Start declaration of a subdomain. Technically the same as H(domain),
+ Start declaration of a sub-domain. Technically the same as H(domain),
but this one should be more intuitive.
GLUE(ns, addr...)
- Specify a glue record for a name server contained within a subdomain
+ Specify a glue record for a name server contained within a sub-domain
it's a primary for. Currently it's an equivalent of DH(ns, addr...).
NS(ns...)
Specify a list of name server names for the current domain
(started by either a SOA or D declaration). Generates NS records.
+DS()
+DS(dsset)
+ Include DS records for the current sub-domain. With no arguments,
+ they are loaded from dss/<sub-domain>. If the name of the sub-domain
+ does not match the name of the DSset (as it frequently happens with
+ reverse zones), you can specify the DSset name explicitly.
+
MX(mx...)
Specify a list of mail exchangers for the current host or domain.
Each mail exchanger should be preceded by a priority. Generates
Generates a series of CNAME records pointing from the aliases
to the current host/domain.
+TXT(text)
+ Specify a TXT record for the current host or domain.
+
+RP(mail, txt)
+ Specify a RP (responsible person) record for the current host or domain.
+ The first argument is a mail address in DNS notation (with `@' replaced
+ by `.' as in the SOA record), the second one is a name of a TXT record
+ with contact information.
+
+SRV(service, protocol, priority, weight, port, target)
+ Specify a SRV (service) record for the current host or domain.
+
CNAME(src, dest)
Generate a CNAME record -- "src" points to "dest".
REVBLOCK(subdomain, min, max)
Generate a series of CNAME records numbered from `min' to `max'
- and pointing to the same name in the given subdomain, finally
- declaring the subdomain as well, so you can continue with its
+ and pointing to the same name in the given sub-domain, finally
+ declaring the sub-domain as well, so you can continue with its
NS records.
Example: REVBLOCK(a, 16, 18) NS(ns.xyzzy.org) yields
a NS ns.xyzzy.org.
This is a very common construct for classless reverse delegations,
- see Section XXX for more details.
+ see Section 6 for more details.
REVERSE(network)
- Switch to reverse mode. From this point on, all output is supressed
+ Switch to reverse mode. From this point on, all output is suppressed
except for ADDR declarations belonging to the specified network which
are automatically converted to PTR records.
4. Configuration variables
~~~~~~~~~~~~~~~~~~~~~~~~~~
There is a fair amount of configuration variables (which are in reality normal
-M4 macros). Each variable has a hard-wired default value which can be overriden
+M4 macros). Each variable has a hard-wired default value which can be overridden
in cf/config by re-defining the variable. Also, all other config files can specify
their local definitions, but you need to be careful to change the variable before
it is used for the first time.
The following variables are available:
NAMED_RESTART_CMD Shell command for restarting the name server daemon
- (default: ndc restart)
+ (default: rndc reload)
-ROOT Root directory of the whole package (default: /etc/named)
CFDIR Directory with config files (default: cf)
-ZONEDIR Directory with zone files (default: zone)
-BAKDIR Directory with backup files (default: bak)
-VERSDIR Directory with version files (default: var)
-ROOTCACHE File with the cache of root nameservers
REFRESH SOA record parameters
RETRY
NSNAME Origin server (default: hostname of your machine)
MAINTNAME Domain maintainer name (default: root@NSNAME)
-BIND_OPTIONS Extra options to put to the options { ...} section of named.conf
+KEYGEN_OPTIONS Extra options given to dnssec-keygen
+ (by default, it selects key type and key size).
+SIGNZONE_OPTIONS Extra options given to dnssec-signzone
+ (by default, it specifies signature validity of 365 days).
+DSFROMKEY_OPTIONS Extra options given to dnssec-dsfromkey
+ (by default, there are none).
-For the timing parameters, the following shortcuts are avaiable:
+For the timing parameters, the following shortcuts are available:
HOURS(n) Convert hours to seconds
MINUTES(n) Convert minutes to seconds
DAYS(n) Convert days to seconds
-For the BIND_OPTIONS, we offer:
-
-FORWARD(ip...) Try to ask the given nameservers first to see if they
- have the reply cached.
-SLAVE(ip...) Pass all non-local requests to the given nameservers.
-
5. Makefile targets
~~~~~~~~~~~~~~~~~~~
The Makefile generated by NSC offers the following targets:
all (default) - update all zone files and reload the daemon
- clean - clean all generated zone files and backups
+ clean - clean all generated zone files, backups, and hashes
clobber - clean + delete Makefile and named.conf
(wise to do after major reconfigurations)
distclean - clobber + delete all version files (use only
6. Classless reverse delegations
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+NSC also supports classless delegations for reverse zones using the mechanism
+described in RFC 2317, i.e. by putting CNAME records to the reverse zone which
+point to records of the same name in a sub-domain which you can delegate directly.
+
+For example if you want to delegate 64-127 in 0.0.10.in-addr.arpa to ns.example.net,
+you create a 64/26 sub-domain (26 is the network prefix length) and add the following
+records to 0.0.10.in-addr.arpa:
+
+ 64 CNAME 64.64/26.0.0.10.in-addr.arpa.
+ 65 CNAME 65.64/26.0.0.10.in-addr.arpa.
+ ...
+ 127 CNAME 127.64/26.0.0.10.in-addr.arpa.
+
+ 64/26 NS ns.example.net.
+
+Then you configure ns.example.net to be a primary name server for the zone
+64/26.0.0.10.in-addr.arpa and put the PTR records there:
+
+ 64 PTR sixty-four.example.net.
+ 65 PTR sixty-five.example.net.
+ ...
+ 127 PTR two-to-seven-minus-one.example.net.
+
+NSC offers special primitives for configuring such delegations, but not limited
+to the sub-domain name syntax shown above (which is recommended by the RFC, but it's
+far from being the only one used in the real world, other possibilities being for
+example 64-127, 64+64 etc.).
+
+The CNAME block can be generated by the REVBLOCK(subdomain-name, low-addr, high-addr)
+directive in the configuration of the whole reverse zone. The example above would
+be written as:
+
+ REVBLOCK(64/26, 64, 127)
+
+The sub-zone can be created automatically like any another reverse zone, you only
+need to use the three-parameter form of the REVERSE directive to specify the
+address range in order to filter out possible hosts falling outside your range.
+
+CAVEAT: The slashes in zone names are automatically translated to @'s when forming
+file names.
+
+Again for the example above, you need to put the following to cf/domains:
+
+ REVERSE(10.0.0.64/26, <list-of-domains-to-gather-the-addresses-from>)
+
+And to cf/64@26.0.0.10:
+
+ SOA(REV(10.0.0.64/26))
+ NS(<list-of-name-servers>)
+ REVERSE(10.0.0, 64, 127)
+
+NOTE: It's usually helpful to configure the primary name server for the parent
+domain (i.e., the one where you configure the delegation and create the CNAME's)
+as a secondary for the sub-zone as well, so if it replies with the CNAME, it will
+include the PTR record pointed to by the CNAME in the additional section of its
+reply, eliminating the need for an extra query.
7. Support for IPv6
~~~~~~~~~~~~~~~~~~~
+NSC also supports IPv6 in a pretty straightforward form: wherever you can write
+an IPv4 address, you can use an IPv6 address as well. Incomplete IP addresses
+or ranges used for specifying address blocks for reverse delegations are replaced
+by network prefixes of the standard form <address>/<prefix-length>.
+
+Example:
+
+ H(ianus, 1.2.3.4, fec0::1234:5678:9abc:def0)
+
+specifies a dual-stack host with both an A record and an AAAA record.
+
+CAVEAT: The backward-compatible IPv6 address syntax with ":v.w.x.y" at the end
+is not supported. All other syntaxes and quirks hopefully are.
+
+
+8. DNSSEC support
+~~~~~~~~~~~~~~~~~
+NSC knows the basics of DNSSEC. It does not handle key management (you need to
+schedule generation and retirement of your keys by other means), but once the
+keys are in place, it uses them for signing zones.
+
+=== Key management ===
+
+Keys live in keys/<zone>/*.(key|private) and they are stored in the usual BIND
+format. To generate a zone-signing key, you can use the following command after
+writing at least rudimentary cf/<zone>:
+
+ bin/key-gen <zone>
+
+If you want a key-signing key, use:
+
+ bin/key-gen <zone> -f KSK
+
+(Generally, you can add arbitrary arguments for BIND's dnssec-keygen. Default
+keygen options can be set in cf/config, see section 4.)
+
+To detect key changes, NSC keeps a hash of all keys for each domain.
+If you edit the keys manually (e.g., to delete a key), you need to recalculate
+the hash by:
+
+ bin/key-update <zone>
+(or without a zone to update all hashes).
+=== Domain signing ===
- in style of RFC 2317. The RFC recommends syntax `net/prefix-len'
- for the subdomains (which is especially nasty for all systems
- storing domains in files with the same name :) ; NSC avoids this
- by automagically translating all slashes in domain names to @'s
- when creating file names)
+All domains whose declarations in cf/domains are wrapped by DNSSEC(`...')
+are automatically signed using all set up keys. If you specify key validity
+period when generating the key, it is respected, but the domains are not
+re-signed automatically when a key becomes valid / ceases to be. If you
+want to modify dnssec-signzone arguments, you can do so in cf/config.
+Beware that all signatures have a limited lifetime (even if the keys do not
+expire). The default lifetime is 365 days, so you need to re-sign your zones
+at least once in a year. The recommended solution is to set up a cron job,
+which touches keys/resign-stamp. A change of timestamp of this file forces
+a re-sign on the next run of make.
-8. Interaction with M4
+=== Subdomains ===
+
+If you want to delegate a signed sub-domain, you need to include DS records
+in the parent zone. Add a DS() macro after declaration of the sub-domain
+in the parent. It loads DS records from dss/<child>.
+
+If the sub-domain is also maintained by NSC, you can generate the DS record
+set automatically by:
+
+ bin/key-delegate <zone>
+
+=== Reverse zones ===
+
+Unlike primary/secondary zones, reverse zones have file names which differ
+from the full domain name. In such cases, keys are named after the file name
+and NSC constructs the full name whenever necessary.
+
+There is one exception where automatic construction is not available:
+delegation of sub-domain keys. In such cases, you need to pass the file
+name of the sub-zone to the DS macro.
+
+
+9. Interaction with M4
~~~~~~~~~~~~~~~~~~~~~~
+All config files are fully-fledged M4 scripts, so you can use any M4 features
+you need, the most helpful one being definition of your own macros by
+ define(`macro_name', `expansion')
-9. Other utilities
-~~~~~~~~~~~~~~~~~~
+However, there is a couple of things you need to care about:
+
+ o The comment character is redefined to `;'. I.e., wherever a semicolon
+ occurs, the rest of the line is a comment which is copied verbatim
+ to the output file (if the output is not suppressed like in case
+ of the cf/domains file).
+
+ o Names starting with 'nsc_' or spelled in all caps are reserved
+ for the NSC itself and unless documented, messing with them can
+ bring surprising results. If you need to use such a name in your
+ zone file (maybe you like to shout in your host names :-) ),
+ quote it like `this'.
-chkdom Checks domains for correctness using the 'host' utility
- (check ftp://ftp.nikhef.nl/pub/network for latest version).
- Use chkdom <domain> <NS> to check specific domain or no
- parameters to check all domains mentioned in cf/domains.
- It's even better to use the Sleuth script mentioned in
- the introduction.
+ o Don't use commas, quotes nor parentheses in your record names.
-convert A simple perl script for conversion of zone files to NSC
- domain files. Requires the DNS module (available from CPAN at
- ftp.cpan.org).
-chkdel A simple perl script for checking of domain delegations --
+9. Other utilities
+~~~~~~~~~~~~~~~~~~
+convert A simple Perl script for conversion of zone files to NSC
+ domain files. Requires the Net::DNS module (available from
+ CPAN at ftp.cpan.org; present in recent versions of Perl).
+ Keep in mind that the script is very simple and its craft
+ is of a very limited kind, so check its output carefully.
+
+chkdel A simple Perl script for checking of domain delegations --
it checks all PRIMARY and SECONDARY records in cf/domains
- against NS records. Requires the DNS Perl module and also
+ against NS records. Requires the Net::DNS module and also
some tweaking of parameters at the top of the script.
projects / nsc-5.git / blobdiff