Normally in network if network administrator using one more DNS server he or she has to route traffic properly.
Explanation:
If still network traffic is heavy in the network the following step has to check by network administrator.
1. Make sure second network is installed properly and properly routed in network.
2. Any tcpip address complicit
3. Disconnect workstation and desktop or laptop one by one to check the network traffic.
4. Finally switch of DSN SERVER or disconnect one by one from network.
After installing second DNS SERVER network is high better to format and reinstall DNS SERVER in the network.
