DNS Problem

Hello,

I have two computers outside of my production network with static ip addresses – they are setup as follows:

Box1
IP: 192.168.1.20
subnet: 255.255.255.0
DNS: 192.168.1.4

Then BOX1 was changed to
IP: 192.168.1.21
subnet: 255.255.255.0
DNS: 192.168.1.4

Box2 was then set to:
IP: 192.168.1.20
subnet: 255.255.255.0
DNS: 192.168.1.4

The problem is when I ping box1 from the production domain it comes up with 192.168.1.20. How can I fix this problem?

If I “ping -a 192.168.1.20” It says box2!!

Thanks