I was at the location and it does not work.
What I'd like to do is to have the IP address given by DHCP server to be always the same for a specific MAC address. ON regular servers, I enter the the IPs and MACs in the dhcpd.conf
This is mostly for laptops. I cannot use fixed IP on the laptops, they travel.
I have tried the hostnames and addresses. It does not assign the IP address for their MAC, but it assigns one from the DHCP pool.