DHCP Server for Ubuntu 18.04 LTS enables computers to request IP addresses and networking parameters automatically from the Internet service provider, reducing the need for an administrator or a user to manually assign IP addresses to all network devices.
This is a quick deployment and ready-to-run image.
Simple and rapid installation. Easy to maintain.
Configuration of DHCP Server for Ubuntu
For DHCP to work, you must open TCP port 10000 in the network settings in Azure Firewall for access via webmin.
After starting the VM, go through the browser to the address https://ip:10000 where ip is the IP address of your virtual machine on Azure.
On the open page, accept the self-signed certificate:

Log in using the username and password of the virtual machine user.
To administer a DHCP server in webmin, on the left menu, go to the section: Servers – DHCP server.
Detailed information on setting up and running a DHCP server:
https://doxfer.webmin.com/Webmin/DHCP_Server