Hi ,
Welcome to our new Microsoft Q&A Platform.
As I understand, you issue is that you have changed a new DHCP server and the IP is in 192.168.100.0 and you want to assign IP addresses in this range. If I misunderstand, please let me know.
Based on my knowledge, the new DHCP can’t work because it locats in different network segments and unable to communicate. I think you can configure a DHCP relay agent. And the flowing link will show you how to add and configure a DHCP relay agent.
https://www.sqa.org.uk/e-learning/NetInf101CD/page_76.htm
Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.
Best Regards,
Candy