Configuring a Dynamic Host Configuration Protocol (DHCP) server

Configuring DHCP options

Global DHCP options are parameters which are not specific to individual subnets and are usually the same for all hosts. Examples are the list of DNS name servers and the name of the local domain.

You can also define DHCP options for sets of subnet, vendor class, user class, and client options by clicking on Generic while defining or modifying an option set. The options defined within a set of options always override the globally defined option. An option defined within a set can override that defined in other sets according to the precedence of the set. See ``DHCP options'' for more information.

NOTE: You can define additional options (user-defined options) with codes in the range 128 through 254 as described in ``Specifying user-defined and vendor-specific options''. Such an option definition applies globally to all subnet, vendor class, user class, and client sets. It is indicated by the tag (global) in the list of available DHCP options.

When configuring a vendor class, you can define vendor-specific options with codes in the range 1 through 254. A vendor-specific option definition only applies to the vendor class for which it is defined. It is indicated by the tag (vendor) in the list of available DHCP options for the vendor class.

To configure options using the DHCP Server Manager:

To add or modify global options, select View Global Options. Select Entry Add if no options are currently defined, or otherwise select Entry Modify.
To modify options defined within an option set, select one of Subnets, Clients, User Classes, Vendor Classes, or User Defined Options from the View menu. Select the option set from those listed, and select Entry Modify.
Configure the options that you want to apply by moving them from the ``Unused'' list to the ``Configured'' list.
To add an option, highlight the option in the ``Unused'' list and click on Add to move it to the ``Configured'' list. Enter the value(s) for the option and click on OK.
To modify an option within a set, highlight it in the ``Configured'' list and click on Edit value. Change its value(s) and then click on OK.
To delete an option from a set, highlight it in the ``Configured'' list and click on Remove to move it to the ``Unused'' list.
If you are defining the set of options for a vendor class, you can create a vendor-specific option by redefining an existing global option. To do this, highlight the global option in the ``Unused'' list and click on Add.
Once you have defined a vendor-specific option, you can select it for use by the vendor class by moving the option to the ``Configured'' list and defining its value.
To modify an existing vendor-specific option, highlight it in the ``Unused'' list and click on Modify.
To delete an existing vendor-specific option, highlight it in the ``Unused'' list and click on Delete.
Click on OK when the ``Configured'' list contains the list of desired options in the set.

An alternative way of removing an option from the global set is to select View

Global Options, select the option to be deleted from those listed, then select Entry

Delete. Click on OK when prompted to confirm the deletion.