DNS: querying route DNS

Matthew Seaman m.seaman at infracaninophile.co.uk
Fri Jan 14 09:08:57 PST 2005

Andrew P. wrote:
> Matthew Seaman wrote:
>> If your ISPs nameservers are unreliable or overloaded, and not giving 
>> you a good service, then one course of action you might consider is 
>> just configuring the named(8) built into your FreeBSD system to do 
>> recursive DNS lookups for you. (And caching -- but that's a given for 
>> any sort of DNS server).  If you (or anyone) is interested I'll be 
>> happy to post a HowTo to the list.

> I'm sure it won't be difficult for anyone to find a named(8) how-to,
> but I'd be very glad to see your post, please. I currently use djbdns,
> but I'm not very happy with it and I'd like to try something else.

Sure.  Assuming you're using 5.3-RELEASE, 5.3-STABLE or better, then 
setting up a recursive-only nameserver is really very simple.

The system comes with BIND-9.3.0 as standard, and it has all of the 
chroot-ing functionality available just by default. All you need do is 
add the following to /etc/rc.conf:


There are several other variables you can use to tweak the named startup 
  via /etc/rc.conf, but basically the default values are good for what I 
want to do here:

named_program="/usr/sbin/named" # path to named, if you want a different 
named_flags="-u bind"           # Flags for named
named_pidfile="/var/run/named/pid" # Must set this in named.conf as well
named_chrootdir="/var/named"    # Chroot directory (or "" not to 
auto-chroot it)
named_chroot_autoupdate="YES"   # Automatically install/update chrooted
                                 # components of named. See /etc/rc.d/named.
named_symlink_enable="YES"      # Symlink the chrooted pid file

You need to do three more things to configure named.  The first is to 
generate the keys that allow rndc(8) to communicate with and control the 
name server:

     # rndc-confgen > /etc/named/rndc.conf

The file consists of two parts: the stuff rndc needs to read, followed 
by the equivalent stuff, but commented out, to go into named.conf:

# Start of rndc.conf
key "rndc-key" {
         algorithm hmac-md5;

options {
         default-key "rndc-key";
         default-port 953;
# End of rndc.conf

# Use with the following in named.conf, adjusting the allow list as needed:
# key "rndc-key" {
#       algorithm hmac-md5;
# };
# controls {
#       inet port 953
#               allow {; } keys { "rndc-key"; };
# };
# End of named.conf

All of those X's will be replaced by a random password hash.

The second thing is to generate the zone files for the localhost and the 
  IPv6 and IPv4 loopback addresses, which you do by running the provided 

     # cd /etc/namedb
     # ./make-localhost

This will write two files into /etc/namedb/master: localhost.rev, and 
localhost-v6.rev which let you resolve the IP numbers and ::1 
respectively as mapping to the hostname 'localhost.'  Once you've 
generated those once, you never need to touch them again.  Nb. Although 
we're setting up a recursive nameserver, it will hold these localhost 
domains authoritatively; a slight exception to the usual rule of not 
mixing recursive and authoritative functions in the same nameserver 
instance.  Pretty much every nameserver in operation provides the 
localhost reverse domain.

The third and final step is to generate a named.conf -- details of the 
configuration file syntax are available in


but something based on the attached example is what you need. This will 
provide a recursive nameservice including both IPv4 and IPv6.  Use 
named-confcheck to syntax check the file:

     % named-checkconf named.conf && echo "Configuration OK"

BIND v9 is in general very picky about the syntax of the configuration 
file, and if it finds an error (usually a missing semi-colon) it will 
silently (except for messages to the system log) refuse to start up.

At last you're ready to fire up named for the first time:

     # /etc/rc.d/named start

This will result in the contents of /etc/namedb being copied into 
/var/named/etc/namedb and a sym-link being created in /etc.  Various 
other necessary bits will be created under /var/named and as a security 
measure, the named daemon will be chroot'ed there when it starts up.

Any time you work on named's config or zone files, always check the 
system log to confirm that named is still happy:

Jan 14 09:08:40 gravitas named[371]: starting BIND 9.3.0 -u bind -t 
Jan 14 09:08:41 gravitas named[371]: command channel listening on
Jan 14 09:08:41 gravitas named[371]: command channel listening on ::1#953

Use rndc(8) to control named during normal use -- it's interesting to 
dump the cache after a day or so's operation to see what weird and 
wonderful places your system has been looking up.



Dr Matthew J Seaman MA, D.Phil.                       8 Dane Court Manor
                                                       School Rd
PGP: http://www.infracaninophile.co.uk/pgpkey         Tilmanstone
Tel: +44 1304 617253                                  Kent, CT14 0JL UK
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# Recursive resolver, for general purpose use.

# Networks/IP numbers from where people are allowed to do recursive
# lookups via this server.  For security reasons, you should limit
# this to just your own networks.  Edit to suit your local setup.

acl allowedusers {;;

# The 'key' and 'controls' blocks should be copied out of
# /etc/namedb/rndc.conf -- I've added an obvious extension so you can
# connect via IPv6 as well.

key "rndc-key" {
        algorithm hmac-md5;

controls {
        inet port 953
                allow {; } keys { "rndc-key"; };
        inet ::1 port 953
                allow { ::1; } keys { "rndc-key"; };

# This logging statement turns on query logging to syslog /by
# default/.  Enable /var/log/all.log by following the instructions in
# /etc/syslog.conf if you want to see the output.  Nb. you will
# probably want to turn off query logging if there are a lot of people
# using the resolver, as it generates quite a bit of output.  You can
# toggle query logging at runtime by using rndc(8).

logging {
        category default {
        category queries {
        category unmatched {

options {
        directory       "/etc/namedb";
        pid-file        "/var/run/named/pid";
        dump-file       "/var/dump/named_dump.db";
        statistics-file "/var/stats/named.stats";

 	# See http://www.onlamp.com/pub/a/onlamp/2003/09/22/vixie.html
	root-delegation-only exclude { "de"; "lv"; "us"; "museum"; };

        listen-on       { any; };
        listen-on-v6    { any; };

	allow-recursion { allowedusers; localhost; };
        allow-transfer { none; };

zone "." {
        type hint;
        file "named.root";

zone "0.0.127.IN-ADDR.ARPA" {
        type master;
        file "master/localhost.rev";
        notify no;
	allow-update { none; };

// RFC 3152
zone "" {
        type master;
        file "master/localhost-v6.rev";
        notify no;
	allow-update { none; };

// RFC 1886 -- deprecated
zone "" {
        type master;
        file "master/localhost-v6.rev";
        notify no;
	allow-update { none; };

# That's All Folks!
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