Opciones Servidor Maestro, permite 2 servidores esclavos.

En el servidor principal(150) se permite la transferencia de zonas a determinados servidores secundarios (22 y 122)

options {
    directory "/var/cache/bind";

    // If there is a firewall between you and nameservers you want
    // to talk to, you may need to fix the firewall to allow multiple
    // ports to talk.  See http://www.kb.cert.org/vuls/id/800113

    // If your ISP provided one or more IP addresses for stable 
    // nameservers, you probably want to use them as forwarders.  
    // Uncomment the following block, and insert the addresses replacing 
    // the all-0's placeholder.

    forwarders {
         80.58.61.250;
         80.58.61.254;
    };

    allow-transfer { 192.168.1.22;
             192.168.1.122;
    };

    auth-nxdomain no;    # conform to RFC1035
    listen-on-v6 { any; };
};