Creating DHCP Scopes
Multiple number of DHCP servers can be used on a single physical network. This becomes possible by dividing the range of addresses to be assigned into multiple scopes. Every scope has useful information. The article discusses in detail the creation of a New DHCP scope in IPv4.
Creating a New Scope in IPv4
As in many cases, in Windows Server 2008 R2, it is the wizard that controls the process of creating a new scope. A scope is created while the process of DHCP is being followed but additional DHCP may be required to be created. The process is simple as long as one is prepared. Before starting the process of creating a new scope, it is best to have information on the following aspects:
- The range of the IP address for which scope has to be created;
- IP addresses to be excluded from the address pool;
- IP addresses that are to be reserved;
- Values for DHCP options that have to be set. This is not a mandatory requirement but may be required for increasing the functionality of the scope.
For creating a scope, under the name of the server, right click on the option IPv4 in the DHCP snap-in. From here use the Action ⇒ New Scope command. This will start the New Scope Wizard. The pages and the steps of the New Scope Wizard are discussed in detail in the following sections.
Setting the Screen Name
Setting up the screen name is the first step of the process. The Scope Name Page allows entering the name and description of the scope. These are displayed by the DHCP snap-in.
Defining the IP Address Range
The next page and the next step is of specifying the IP Address Range. On this page the start and the end IP addresses for the range are specified. The wizard does not perform extensive checks on the addresses that are entered and the correct subnet mask for the range is created automatically. The subnet mask can also be modified.
This page allows defining the exclusion ranges. Exclusions are TCP/IP numbers that are included in the pool but are not issued to the clients. For excluding an address, specify it in the Start IP Address field. The
End IP Address field is also required to be filled for specifying the exclusion.
Setting a Lease Duration
This page allows defining the duration for which a device uses an assigned IP address before the lease is renewed. Eight days is the default duration while your network may require a longer or shorter duration.
Configuring Basic DHCP Options
The next page, that is, the Configure DHCP Options page permits setting up the basic DHCP options like the default gateway and the DNS settings. The options can be configured at a later stage also but it is recommended that the options be assigned before activating the scope. The various options that can be configured on this page are:
- Configuring a Router: This is the first option on the router page. Here the IP addresses of the routers for the outbound traffic are entered. The Up and Down button can be used for arranging the order of the addresses.
- Configuring a Router: Providing DNS Settings: On the Domain Name and DNS Servers page, the DNS servers and the main domain that has to be passed down is specified. In most cases one may want to specify a minimum of one DNS server by entering the DNS name or the IP address. The domain suffix can also be specified.
- Providing WINS Settings: in case the WINS - Windows Internet Name Service is being used on the network, the DHCP can be configured as it passes the WNS server addresses to the Windows clients. Addresses of several servers can be added and their placing shifted. Some of the common options that can be set up on a DHCP server:
|03 router||This is used for providing a list of available routers or default gateways present on the same subnet|
|006 DNS Servers||This provides a list of DNS servers|
|015 DNS Domain Name||This provides the DNS suffix|
|28 oadcast Address||This allows configuring the broadcast address in case it is different from the default.|
|44 INS/NBNS Servers||This allows configuring the IP addresses of WINS servers|
|46 WINS/NBT Node Type||This is used for configuring the preferred NetBIOS name resolution method.
Four settings are possible -
|051 Lease||Used for configuring a special lease duration|
Activating the Scope
This page allows activation of the scope right after its creation. The default setting allows the scope to be activated until you select the option allowing activation at a later stage.