/var/named/master/localhost.zone

$TTL    604800

@       IN     SOA     localhost. root.localhost. (
                       2016121801      ; serial
                       604800          ; refresh
                        86400          ; retry
                       2419200         ; expiry
                        604800         ; minimum
                       )
;
        NS localhost.

localhost.        IN      A       127.0.0.1