User guide

Chapter 4. Configuring Special Features 89
Usually users will not need to define their own option types. The list of predefined option types based on RFC
1533 can be shown by typing dhcp list definedoptions.
Commands
The following commands are available for adding/deleting option types:
dhcp add <code> <min> <max> <type>
To list option types that are currently defined, use:
dhcp list definedoptions...
To list the definitions for all known options, use:
dhcp list definedoptions
To get help information, use:
dhcp list definedoptions?
To list the definition for option 1, if option 1 is defined, type:|
dhcp list definedoptions 1
To list the definition for all options that are well-known AND have a name starting with ÒhÓ, type:
dhcp list definedoptions h
Example:
To define a new option with a code of 128, a minimum number of IP addresses of 1, a maximum number of
IP addresses of 4, of type ÒIP addressÓ, type:
dhcp add 128 1 4 ipAddress
This information implies that:
¥ Some DHCP client will know about the option with code 128.
¥ Option 128 allows IP addresses.
¥ The server can have a minimum of 1 IP address.
¥ The server can have up to 4 IP addresses.
¥ The administrator will still need to set the option value either globally, specific to a subnetwork, or
specific to a client for the option to have any meaning.
To delete the definition of the option with code 128, type:
dhcp del 128
The values for this option that have been set globally, specific to a subnetwork, or specific to a client will not
be removed. The administrator must remove those values explicitly. Well-known type option codes cannot be
changed or deleted.
Configuring BootP/DHCP Relays
BootP/DHCP Relays are used by system administrators when the DHCP configuration parameters are acquired
from a BootP/DHCP server other than the routerÕs DHCP server.
This feature allows configuration information to be centrally controlled. Enabling a BootP/DHCP Relay disables
DHCP on the router because, by definition, only one policy mechanism can be supported.