On your old server run the following:
Where:
- 192.168.1.1 is your primary OLD IP Address
- 192.168.2.1 is your secondary OLD IP Address
- 172.16.16.1 is your primary NEW IP Address
- 172.16.17.1 is your secondary NEW IP Address
So, all the DNS queries performed against your OLD server, will receive the new IP addresses as answers.
Hope it helps,
bye Kess.