options {
  directory "/var/cache/bind";
  listen-on port 53 { any; };
  allow-query { any; };
  recursion no;
};

zone "sub.example.com" {
  type master;
  file "/etc/bind/db.sub.example.com";
};

logging {
  channel default_log {
    file "/var/log/named.log";
    severity info;
    print-time yes;
  };
  category default { default_log; };
};