IBM Heritage user manual Request, Require, Send, Other declarations Reject

9-4 DHCP Client Configuration

Options. DHCP Options are defined in [3], although an DHCP client only supports a limited subset of those described there

9.2.1 Request

request [ option ] [, ... option];

The request statement causes the client to request that any server responding to the client send the client its values for the specified options. Only the option names should be specified in the request statement - not option parameters.

9.2.2 Require

require [ option ] [, ... option ];

The require statement lists options that must be sent in order for an offer to be accepted. Offers that do not contain all the listed options will be ignored.

9.2.3 Send

send { [ option declaration ] [ ... option declaration ] }

The send statement causes the client to send the specified options to the server with the specified values. Options that are always sent in the DHCP protocol should not be specified here, except that the client can specify a requested-lease-timeoption other than the default requested lease time, which is two hours (this would normally be done on a per-interface basis: see section 6.3.2). The other obvious use for this statement is to send information to the server that will allow it to differentiate between this client and other clients or kinds of clients.

9.3 Other declarations

9.3.1 Reject

reject ip-address;

The reject statement causes the DHCP client to reject offers from servers who use the specified address as a server identifier. This can be used to avoid being configured by rogue or misconfigured dhcp servers, although it should be a last resort - better to track down the bad DHCP server and fix it.