• Setup and run named (aka BIND) on your system
• Go to your registrar and add a 'glue' record for this server (e.g. have ns1.blah.com point to the ip of the box on which named is running). You can then re-use this name server for other domains.
• Add a stanza like this to your /etc/named.conf file

zone "blah.com" IN {
type master;
file  "blah.com.db";
allow-update { none; };
};

• Go here to make a zone file, or make one based on the example below. Either way, save it to /var/named/chroot/var/named/blah.com.db

; BIND db file for ijklmnopq.com

$TTL 86400

@       IN      SOA     ns1.blah.com.      mail.blah.com. (
                        2007011501      ; serial number YYMMDDNN
                        28800           ; Refresh
                        7200            ; Retry
                        864000          ; Expire
                        86400           ; Min TTL
                        )

                NS      ns1.blah.com.


$ORIGIN blah.com.

        IN      A       216.224.124.98
www     IN      A       216.224.124.98

• restart named
• test by doing dig @localhost blah.com. Look in the answer section.

-- MattWalsh - 15 Jan 2007