Adding Subnets

Subnet Description: Tag name to identify the subnet.
Network Address: 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 sub- net. Such addresses are specified using the range declaration. The subnet-number should be an IP address. The mask should be an IP address of the subnet being described. The subnet number, together with the mask, are sufficient to determine whether any given IP address is on the specified subnet. Although a mask must be given with every subnet declaration, 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 to set the desired subnet mask, since any subnet-mask option statement will override the subnet mask declared in the subnet statement.
Mask: The mask option specifies the client's subnet mask. If no subnet mask option is provided anywhere in scope, as a last resort Dhcpd will use the subnet mask from the subnet declaration for the network on which an address is being assigned. However, any subnet-mask option declaration that is in scope for the address being assigned will override the subnet mask specified in the subnet declaration. 
Address Range: For any subnet on which addresses will be assigned dynamically, there must be at least one range statement. The range statement gives the lowest and highest IP addresses in a range. All IP addresses in the range should be in the subnet in which the range statement is declared. 
Dynamic Bootp: The dynamic bootp flag may be specified if addresses in the specified range may be dynamically assigned to BOOTP clients as well as DHCP clients. When specifying a single address, high-address can be omitted.
Lease Time: Tells the server how many seconds long a default address lease should be. The client can request that the address be leased for a specific period of time. If it does, it is assigned the address for that period of time, given some restrictions. Frequently, clients do not request a specific lifetime for an address lease. When that happens, the default-lease-time is used. In the example, the default lease is set to one day (86400 seconds).
Max Lease Time: Sets the upper limit for how long an address can be leased. Regardless of the length of time requested by the client, this is the longest address lease that dhcpd will grant. The life of the lease is specified in seconds. In the example, it is one week.

Options

Domain Name: This option specifies the domain name that client should use when resolving hostnames via the Domain Name System.
Gateway: The gateway option specifies a list of IP addresses for gateways on the client's subnet. Gateways should be listed in order of preference
Subnet Mask: The subnet mask option specifies the client's subnet mask. If no subnet mask option is provided anywhere in scope, as a last resort Dhcpd will use the subnet mask from the subnet declaration for the network on which an address is being assigned. However, any subnet-mask option declaration that is in scope for the address being assigned will override the subnet mask specified in the subnet declaration.
Broadcast Address: This option specifies the broadcast address in use on the client's subnet.
Static Route: This option specifies a list of static routes that the client should install in its routing cache. If multiple routes to the same destination are specified, they are listed in descending order of priority.
The routes consist of a list of IP address pairs. The first address is the destination address, and the second address is the router for the destination.
The default route (0.0.0.0) is an illegal destination for a static route. To specify the default route, use the Gateway option.
Name Server: The server-name statement specifies the name of the boot server name to use. This is also not used by the standard client configuration script.
DNS Server: The domain-name-servers option specifies a list of Domain Name System available to the client. Servers should be listed in order of preference.
Time Server: The time-server option specifies a list of time servers available to the client. Servers should be listed in order of preference.
NIS Domain: This option specifies the name of the client's NIS (Sun Network Information Services) domain. The domain is formatted as a character string consisting of characters from the NVT ASCII character set.
NIS Server: This option specifies a list of IP addresses indicating NIS servers available to the client. Servers should be listed in order of preference.

Netbios 

NetBios server: The NetBIOS name server (NBNS) option specifies a list of name servers listed in order of preference. NetBIOS Name Service is currently more commonly referred to as WINS.
Netbios Scope: The NetBIOS scope identifier is an optional string of characters that identify different logical NetBIOS networks that run on the same physical TCP/IP network.
In most configurations the NetBIOS scope identifier does not need to be changed. The simplest way to configure NetBIOS is to use a single logical network. If you think that you need to use the scope identifier, make sure you fully understand the implications of changing it before doing anything. If you do change the identifier, you should list all the NetBIOS nodes in your network and keep a record of which scope identifier is assigned to which node.
Keeping track of all the scope identifiers in a NetBIOS network can be complicated and time consuming. Avoid using this feature unless you have a very specific need for it.
Before setting the value of the scope identifier, check its value on the other machines in the network. If you have MS-DOS or OS/2 workstations on the network, the NetBIOS scope identifier should be set to NULL on all machines on the network. Many implementations of NetBIOS for TCP/IP allow you to use only the NULL scope identifier. If you have any other AFPS-compatible machines on the network, check their documentation for restrictions.
Netbios node type: The NetBIOS node type option allows NetBIOS over TCP/IP clients which are configurable to be configured as described in RFC 1001/1002. The value is specified as a single octet which identifies the client type.

Possible node types are:

1

B-node: Broadcast - no WINS

2

P-node: Peer - WINS only.

4

M-node: Mixed - broadcast, then WINS

8

H-node: Hybrid - WINS, then broadcast