Caching only dns server

You can build a caching only dns server as a forwarder (proxy) or without zones except db.root (classical caching-only).

forwarder

options {
   forwarders { 10.123.188.150; 10.123.68.18; };
   forward only;
   allow-query { any; };
   allow-query-cache { any; };
   allow-transfer { none; };
   allow-update-forwarding { none; };
   allow-notify { none; };
};

caching-only

options {
   directory "/var/cache/bind";
   allow-query { any; };
//   allow-recursion { any; };
   recursion yes;
};

zone "." {
   type hint;
   file "/etc/bind/db.root.intra";
};

// be authoritative for the localhost forward and reverse zones, and for
// broadcast zones as per RFC 1912

zone "localhost" {
   type master;
   file "/etc/bind/db.local";
};

zone "127.in-addr.arpa" {
   type master;
   file "/etc/bind/db.127";
};

zone "0.in-addr.arpa" {
   type master;
   file "/etc/bind/db.0";
};

zone "255.in-addr.arpa" {
   type master;
   file "/etc/bind/db.255";
};

For an intranet the db.root.intra contains the internal root server.

.                               3600000  IN  NS    NS1.DNS.SERVICE.BLA.NET.
NS1.DNS.SERVICE.BLA.NET.       3600000      A     10.123.188.150
.                               3600000  IN  NS    NS2.DNS.SERVICE.BLA.NET.
NS2.DNS.SERVICE.BLA.NET.       3600000      A     10.123.68.18