$origin example.pt.
$TTL 3600      ; 1 hour
@               IN     SOA    ns01.example.pt. admin.example.pt. (
                        2013111801	; serial
                        14400           ; refresh (4 hours)
                        3600            ; retry (1 hours)
                        604800          ; expire (1 week)
                        300             ; minimum (5 minutes)
                        )
                IN      NS      ns01.example.pt.
                IN      NS      ns02.example.pt.
ns01		IN	A	127.0.0.1
ns02		IN	A	127.0.0.2