example1.conf

view "INTERNAL" {
    match-clients { 192.168.1.0/24; };
    server 192.168.1.11 { keys INTERNAL; };
    server 192.168.1.12 { keys INTERNAL; };
    zone "example1.com." in {
        type slave;
        file "slaves/example1.com.internal";
        masters { 192.168.1.11 key "INTERNAL";
                  192.168.1.12 key "INTERNAL";
        };

        allow-notify {  192.168.1.11;
                        192.168.1.12;
        };
        transfer-source 192.168.1.13;

        multi-master yes;

    };
};