One of the host specific definitions is hardware, which describes the specific hardware. Right now, only the ethernet and token-ring hardware types are supported. The syntax here is to list the type of hardware, followed by the physical address of the card (i.e., the MAC address). For example, you might have something like this:
This example says that the machine saturn has an Ethernet card with the MAC address 00:50:04:53:F8:D2, and it is to be assigned the fixed address 192.168.42.3.
Sometimes you need to specify options for a number of machines on your network without having to treat them as a separate subnet. For example, you could define a subnet for a group of machines and then apply specific options to just that subnet. However, this means that you will generally have to specify all of the necessary configuration options; plus, these special nodes obviously cannot have IP addresses in the same subnet as the others.
To overcome this limitation, you can group machines together using the group keyword. This way, all the options included within the group definition apply to that group. As with subnets, this keyword can also specify individual hosts with the group. For example:
