subnet 192.168.222.0 netmask 255.255.255.0 {
  option routers 192.168.222.10;
  option domain-name-servers 192.168.222.10;

  class "RHEL" {
    match if substring (option vendor-class-identifier, 0, 4) = "RHEL";
  }
  pool {
    allow members of "RHEL";
    range 192.168.222.100 192.168.222.200;
  }
  pool {
    deny members of "RHEL";
    range 192.168.222.201 192.168.222.220;
  }
}