i'm using ubuntu 12.04 LTS

I want to host certain domain name, example.com to my server:

Note: i've replace the real domain name to example.com and the server ip to 198.23.xx.xx

$ vi resolv.conf

nameserver 8.8.8.8



$ vi named.conf.local

zone "example.com" {
type master;
file "/etc/bind/db.example.com";
};

zone "example2.com" {
type master;
file "/etc/bind/zones/example2.com.db";
};



$ vi db.example.com
;
; BIND data file for local loopback interface
;
$TTL 604800
@ IN SOA dns1.example.com. root.example.com. (
2013041413 ; Serial
604800 ; Refresh
86400 ; Retry
2419200 ; Expire
604800 ) ; Negative Cache TTL
;
@ NS dns1
dns1 A 198.23.xx.xx
@ A 198.23.xx.xx
@ AAAA ::1


$ named-checkzone example.com /etc/bind/db.example.com
zone example.com/IN: loaded serial 2013041413
OK


$ dig example.com

; <<>> DiG 9.8.1-P1 <<>> example.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 62392
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;example.com. IN A

;; Query time: 1017 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Sun Apr 14 20:23:54 2013
;; MSG SIZE rcvd: 38


May I know if something is wrong with my configs?

Thanks