A record always shows the old ip for my first dns

[black&white]

Hi,
i have a problem with A record.

I have moved all my accounts to a new server, then i changed the ips for my 2 dns.

After a week i have noticed that, typing the query

host -t a ns1.mydns.com

i still see the old ip even if my old server has been removed.

(for the ns1 i see the old ip also on dnsstuff.com)

How is it possible? The zone dns for the master domain is ok, where's the old IP on my new server??

Please help me.

Thank you

[black&white]

I have modified the file

/var/named/ns1.mydns.com.db

and now everything it's ok.