Thank you very much for your reply. This configuration is perfect (I tested it and it's ok!), however, it works if I use only one machine. Because when I ask an entry in the second machine with "dig 789.123.ons.com" (in effect in 10.10.10.12, that the address of my second machine, I added the product "789") I receive this error:

Code:
; <<>> DiG 9.9.2-P1 <<>> 789.123.ons.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 12004
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;789.123.ons.com.        IN    A

;; AUTHORITY SECTION:
123.ons.com.        86400    IN    SOA    123.ons.com. 123.ons.com. 2013102500 604800 86400 2419200 86400

;; Query time: 1 msec
;; SERVER: 127.0.1.1#53(127.0.1.1)
;; WHEN: Fri Oct 25 13:57:47 2013
;; MSG SIZE  rcvd: 84

I have the correct answer only with the request "dig @10.10.10.12 789.123.ons.com".

Thank you!