Creating DHCP Scopes Using DHCP Manager

The information in this article applies to:

• Microsoft Windows NT Workstation versions 3.5, 3.51, and 4.0
• Microsoft Windows NT Server versions 3.5, 3.51, and 4.0

SUMMARY

A DHCP scope is an administrative grouping of computers running the DHCP Client service. You create a scope for each subnet on the network to define parameters for that subnet.

Each scope has the following properties:

1. A unique subnet mask to determine the subnet related to a given IP address.

2. A scope name assigned by the administrator when the scope is created.

3. Lease duration values to be assigned to DHCP clients with dynamic addresses.

MORE INFORMATION

You MUST use DHCP Manager to create, manage, or remove scopes. The DHCP database file (Dhcp.mdb) is a JET database that cannot be read by Microsoft Access or other application editors.

To create a new DHCP scope, select the server in the DHCP Manager window, and on the Scope menu, click Create.

A pop-up window is displayed requiring all necessary information to configure the DHCP Server. To configure the new scope, type the appropriate information into the following fields:

IP Address Pool

Field          Description

End address    Specifies the last IP address of the scope for the clients
Subnet mask    Specifies the subnet mask for the client subnet

Exclusion Range

By specifying addresses to be excluded from a range, DHCP Manager will not lease these addresses to requesting clients. An example of this is a UNIX Tower or similar machine that cannot be reconfigured with a static IP address outside of the intended/defined scope (for example, a corporate DNS).

To implement several address scopes within one subnet on a single DHCP server, create one continuous IP address range that includes all available addresses within the subnet. Then, exclude necessary addresses or ranges from within the defined scope.

For example:

   Defined scope: 192.192.192.1 through 192.192.192.200
   Excluded: 192.192.192.5 and 192.192.192.10 through 192.192.192.50
   Available addresses: 192.192.192.1 through 192.192.192.4, 192.192.192.6
   through 192.192.192.9, and 192.192.192.51 through 192.192.192.200

Lease Duration Unlimited

This option specifies that the DHCP lease assigned to a client will never expire. This is not a recommended option and should be substituted through the use of client reservations.

Lease Duration Limited to

The number of days, hours, and minutes that a DHCP client lease is available before it must be renewed.

Name

The scope name is the name that describes this subnet and is displayed after the IP address in DHCP Manager. The name can include any combination of letters, numbers, hyphens, underscores, or blank characters.

Comment

This is an optional field.