How to accept option-12(hostname) sent by client and update records on server side to change hostname of a system

I have created a internal network using Oracle Vm virtualbox manager, and i have set up dhcp and dns server in a minimal centos7. My network consist of 3 other minimal centos7 (to be used as client side). I am trying to change the hostname of a client system in network from client side by configuring option 12 of dhcp protocol. i have used tcpdump tool and captured packet on server side in network to verify the DHCP_HOSTNAME sent by client is sent in packet. i want to know what server side config i need to do in dhcp/dns to accept option-12 sent by client and map it with it's respective ip address.