LinuxQuestions.org - server can't find mydomain.com: SERVFAIL

hi all,
my os is ubuntu and i have install "bind9 dnsutils".
I think, i have a problem with my dns configuration. This is what i get when i type a few commands for checking my dns, where my full hostname is server mydomain.com and ip is 192.168.1.1.

[root@server root]# host server
Host server not found: 3(NXDOMAIN)

[root@server root]# host 192.168.1.1
Host 1.1.168.192.in-addr.arpa not found: 2(SERVFAIL)

[root@server root]# host mydomain.com
Host mydomain.com not found: 2(SERVFAIL)

[root@server root]# nslookup server
Note: nslookup is deprecated and may be removed from future releases.
Consider using the `dig' or `host' programs instead. Run nslookup with
the `-sil[ent]' option to prevent this message from appearing.
Server: 192.168.1.1
Address: 192.168.1.1#53

** server can't find server: NXDOMAIN

[root@server root]# nslookup 192.168.1.1
Note: nslookup is deprecated and may be removed from future releases.
Consider using the `dig' or `host' programs instead. Run nslookup with
the `-sil[ent]' option to prevent this message from appearing.
Server: 192.168.1.1
Address: 192.168.1.1#53

** server can't find 1.1.168.192.in-addr.arpa: NXDOMAIN

[root@server root]# nslookup mydomain.com
Note: nslookup is deprecated and may be removed from future releases.
Consider using the `dig' or `host' programs instead. Run nslookup with
the `-sil[ent]' option to prevent this message from appearing.
Server: 192.168.1.1
Address: 192.168.1.1#53

** server can't find mydomain.com: SERVFAIL

[root@server root]# dig server

; <<>> DiG 9.2.2-P3 <<>> server
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 61467
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;server. IN A

;; AUTHORITY SECTION:
. 10431 IN SOA a.root-servers.net. nstld.verisign-grs.com. 2003112501 1800 900 604800 86400

;; Query time: 1 msec
;; SERVER: 192.168.1.1#53(192.168.1.1)
;; WHEN: Wed Nov 26 09:20:54 2003
;; MSG SIZE rcvd: 99
[root@server root]# dig 192.168.1.1

; <<>> DiG 9.2.2-P3 <<>> 192.168.1.1
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 26844
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;192.168.1.1. IN A

;; AUTHORITY SECTION:
. 10800 IN SOA a.root-servers.net. nstld.verisign-grs.com. 2003112501 1800 900 604800 86400

;; Query time: 122 msec
;; SERVER: 192.168.1.1#53(192.168.1.1)
;; WHEN: Wed Nov 26 09:21:24 2003
;; MSG SIZE rcvd: 104

[root@server root]# dig mydomain.com

; <<>> DiG 9.2.2-P3 <<>> mydomain.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 30477
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;mydomain. IN A

;; Query time: 1 msec
;; SERVER: 192.168.1.1#53(192.168.1.1)
;; WHEN: Wed Nov 26 09:21:56 2003
;; MSG SIZE rcvd: 40

plz help to fix these errors.