Technical data

79
Setting Option Values
Administrators will want to set the values for global options, for options specific to a subnetwork, or for options
specific to a client lease.
Note:
See RFC 2131/2132 for the description of various options.
Concepts
The server returns values for options explicitly requested in the client request. It selects the values to return
based on the following algorithm:
1. If the value is defined for the client, then the server will return the requested value for an option.
2. If the value for the option has not been set for the client, then the server returns the value option if it has
been defined for the subnetwork.
3. If the valueoption does not exist for the client AND does not exist for the subnetwork, then the server
returns the value option if it has been defined globally.
4. If the value option is not defined anywhere, the server will NOT return any value for that option in its
reply to the client request.
Important:
When replying to a client request, the server does:
•Not
return any option values NOT requested by the client.
•Not
support the definition of a "class" of clients.
•Not
return any non-default option values UNLESS the client requests the option value AND the server
has a value defined for that option.
•Not
return any non-default values on the clients subnet UNLESS the client requests the value for that
option.
Commands for global option values
To set the value for a global option, use:
dhcp set valueoption <
code
> <
value
>...
The code can be a number between 1 and 61 or a keyword.
To see the list of predefined and user-defined options, use:
dhcp list definedoptions
To clear the value for a global option, use:
dhcp clear valueoption <
code
>