DNS Problem

Dear sir,

We have a system that is connected with modem & internet. So when I ping this system. It shows the IP of Modem not its LAN.

Ex.

My computer Name Is : ABC
It’s IP Address is - 192.168.0.1
It’s Modem IP Address 192.168.1.2

When I Ping ABC

It shows

Reply from 192.168.1.2 bytes ……..
Reply from 192.168.1.2 bytes ……..
Reply from 192.168.1.2 bytes ……..
Reply from 192.168.1.2 bytes ……..

It has to show 192.168.0.1 but not. Why this is happening