resolve dns conflict

Hi all
I am new to this group so please excuse me if the question is not fit
here.
I tried to set up a home network (domain is home.net ) using redhat as
the dns server. the name I give the server is ibm.home.net.

so the zone file home.net.zone is (/var/named/home.net.zone)

$TTL 86400
$ORIGIN home.net.
@ IN SOA ibm.home.net. admin.home.net (
2004042601 ; serial (d.
adams)
3H ; refresh
15M ; retry
1W ; expiry
1D ) ; minimum

IN NS ibm.home.net.
IN MX 10 mail.home.net.
ibm IN A 192.168.1.8
www IN A 192.168.1.8
mail IN A 192.168.1.8
ftp IN A 192.168.1.8


I also defined the named.conf file. in /etc/named.conf there is a
section looks like this:

zone "home.net" IN {
type master;
file "home.net.zone";
allow-update { none; };
};



The problem is out in internet there are servers with name
ibm.home.net and mail.home.net,...
when I use nslookup, it returns those servers ip addresses from
internet instead from my dns.
But when I ping ibm.home.net, it returns local ip address 192.168.1.8.

Any idea?

Thanks.


nslookup
> home.net
Server: 68.168.240.5
Address: 68.168.240.5#53

Non-authoritative answer:
Name: home.net
Address: 64.40.102.44
> www.home.net
Server: 68.168.240.5
Address: 68.168.240.5#53

Non-authoritative answer:
Name: www.home.net
Address: 64.40.102.44
> ibm.home.net
Server: 68.168.240.5
Address: 68.168.240.5#53

Non-authoritative answer:
Name: ibm.home.net
Address: 72.51.27.51