From LedHed's Wiki
Overview
Current versions of Linux distros are obtaining DHCP leases with Randomized MAC addresses which I find aggravating when trying to track down a host by MAC. It also blows up a DHCP reservation if you re-install an OS on the same Hardware/VM.
Solution
echo "send dhcp-client-identifier = hardware;" >>/etc/dhcp/dhclient.conf rm /var/lib/dhcp/* systemctl restart networking
References
https://superuser.com/questions/1553094/force-to-use-mac-address-as-dhcp-client-id-on-debian-buster