Changing DHCP Option Default Values

You can change the default values for the predefined and custom DHCP options for configuring clients. For example, you could change the default values for these built-in options:

• 3 = Router, to specify the IP addresses for the routers on the subnet
• 6 = DNS Servers, to specify the IP addresses of the DNS name servers used at your site
• 15 = Domain Name, to specify the DNS domain names to be used for host name resolution

Options that take an array of IP addresses have a default value of 0.0.0.0. You should reset the default value of any such options you intend to use or be sure to set a different value when you assign the option either globally or for a selected scope, as described in "Assigning DHCP Configuration Options" earlier in this chapter.

To change a DHCP option value

1. From the DHCP Options menu, choose Defaults.

2. In the Option Class list in the DHCP Options: Default Values dialog box, select the option class for which you want to change values.
3. If you want to change the default value for an option, select the option you want to change in the Option Name list, choose the Edit button, and then type a new value in the Value box.

Choosing the Edit button displays a special dialog box for editing strings, arrays of IP address, or binary values. For information about using the special editing dialog boxes, see the online Help for DHCP Manager.

4. If you want to change basic elements of a custom option, select it in the Option Name list, and then choose the Change button.

You can change the name, data type, identifier, and comment for a DHCP option, following the procedures described earlier in "Creating New DHCP Options."

5. When you complete all the changes you want to make, choose the OK button.