To assign a certain IP address to a host in your network, add the "host" block to your /etc/dhcp/dhcpd.conf file. In this example, the client PC that has MAC address 00:50:56:A8:8C:AB will be assigned IP address 192.168.0.201.

subnet 192.168.0.0 netmask 255.255.255.0 {
  option routers                  192.168.0.1;
  option subnet-mask              255.255.255.0;
  option domain-name-servers      dns1.example.com, dns2.example.com;
  default-lease-time              43200;
  max-lease-time                  86400;
  range                           192.168.0.100 192.168.0.254;

  host pc1 {
   option host-name "pc1.example.com";
   hardware ethernet 00:50:56:A8:8C:AB; 
   fixed-address 192.168.0.201;
  }

}

The /var/log/messages file should show that the DHCPD server assigned IP address 192.168.0.201 to the host.

~]# cat /var/log/messages
Jun 25 17:29:45 dhcp1 dhcpd: DHCPDISCOVER from 00:50:56:A8:8C:AB (Windows) via eno16777984
Jun 25 17:29:45 dhcp1 dhcpd: DHCPOFFER on 192.168.0.201 to 00:50:56:A8:8C:AB (Windows) via eno16777984
Jun 25 17:29:45 dhcp1 dhcpd: DHCPREQUEST for 192.168.0.201 (192.168.0.4) from 00:50:56:A8:8C:AB (Samsung) via eno16777984
Jun 25 17:29:45 dhcp1 dhcpd: DHCPACK on 192.168.0.201 to 00:50:56:A8:8C:AB (Windows) via eno16777984