subnet subnet-number netmask netmask {
   [ parameters ]
   [ declarations ]
 }

The subnet statement is used to provide dhcpd with enough information to tell whether or not an IP address is on that subnet. It may also be used to provide subnet-specific parameters and to specify what addresses may be dynamically allocated to clients booting on that subnet. Such addresses are specified using the range declaration.

The subnet-number should be an IP address or domain name which resolves to the subnet number of the subnet being described. The netmask should be an IP address or domain name which resolves to the subnet mask of the subnet being described. The subnet number, together with the netmask, are sufficient to determine whether any given IP address is on the specified subnet.

A netmask must be given with every subnet declaration. However, it is recommended that if there is any variance in subnet masks at a site, a subnet-mask option statement be used in each subnet declaration. This is to set the desired subnet mask, since any subnet-mask option statement will override the subnet mask declared in the subnet statement.