$ORIGIN .
$TTL 300	; 5 minutes
example			IN SOA	mname1. . (
				2          ; serial
				20         ; refresh (20 seconds)
				20         ; retry (20 seconds)
				1814400    ; expire (3 weeks)
				3600       ; minimum (1 hour)
				)
example.		NS	ns2.example.
ns0.example.		A	10.53.0.4

$ORIGIN example.
a			A	10.0.0.1
			MX	10 mail.example.

mail			A	10.0.0.2