nsupdate (bind9)

gistfile1.txt

cat <<TSTZONE
// file: dynamic.foo.bar.db
$TTL 86400 ; 1 minute
@		IN	SOA	dynamic.foo.bar. root.foo.bar. (
					2001072010 ; serial
					10800      ; refresh (3 hours)
					3600       ; retry (1 hour)
					1814400    ; expire (3 weeks)
					86400      ; minimum (1 day)
				)
@			NS	ns.foo.bar.
hostname	60	IN	A	1.2.3.4
TSTZONE

cat <<KEYFILE
// file: dynamic.foo.bar.keys
key "host.dynamic.foo.bar" {
        algorithm hmac-md5;
        secret "QWERTYUIOPASDFGHJKLZ==";
};
KEYFILE

cat <<CONFLOCAL
// file: name.conf.local
include "/etc/bind/dynamic.foo.bar.keys";

zone "dynamic.foo.bar" {
    type master;
    file "/etc/bind/dynamic.foo.bar.db";
    update-policy {
        grant *.dynamic.foo.bar self dynamic.foo.bar.;
    };
};
CONFLOCAL

cat <<UPDATE | nsupdate -k /path/to/KEYFILE
server 127.0.0.2
zone dynamic.foo.bar.
update delete hostname.dynamic.foo.bar.
update add hostname.dynamic.foo.bar. 600 A 1.2.3.5
send
UPDATE