Question about "Bogus LOOPBACK" message

[Takahiro Sato]

Hello, 

I am in trouble with DNS log message(syslog) of internal DNS,

"sysquery : query(SOME-DOMAIN-NAME) Bogus LOOPBACK A RR (localhost:127.0.0.1)
 learn (A=localhost:NS=A.B.C.D)"

(*) A.B.C.D is External DNS server address.

If anyone have any idea, please teach me about this.

Thanks!

This illustrates my DNS server environment.

                  THE INTERNET
                 /             \
                /               \
               /                 \
 |---------------|  forward    |---------------|
 | Internal DNS  |------------>| External DNS  |
 | (foo.prv)     |  root NS    |  (bar.xyz)    |
 |               |------------>|               |
 |---------------|             |---------------|
        |
        | private network
        |
    ---------
    |Client |
    ---------

Internal DNS
   Multi-homed DNS(it is connected to private network
   and INTERNET).  It is authority of foo.prv that is
   private network zone. Query of the name other than 
   "foo.prv" is forwarded to external DNS. If its 
   forwarded (recursive) query is not answered, then
   internal DNS sends (non-recursive) query to external
   DNS(as root nameserver).

External DNS
   This nameserver is authority of "bar.xyz.". It's 
   connected to INTERNET.

Internal DNS configuration like this, 

  options {
          forwarders {
                  A.B.C.D;   // it's External DNS's IP Address;
          };
  };

  zone "foo.bar" in {
          type master;
          file "db.foo.bar"; // private network
  };

  zone "10.in-addr.arpa" in {
          type master;
          file "db.10";
  };

  zone "." in {
          type hint;
          file "root.cache"; // In "root.cache", External DNS
                      // is specified as ROOT nameserver.
  };

---
E-mail : t_sato at rbec.co.jp