IBM ADSL Bridge/ Router Heritage - Manual (Page 130)

Heritage Series ADSL Bridge/ Router
8-7 DHCP Server Operation
Host
host hostname {
[ parameters ]
[ declarations ]
}
There must be at least one host statement for every BOOTP client that is to
be served. Host statements may also be specified for DHCP clients,
although this is not required unless booting is only enabled for known
hosts. If it is desirable to be able to boot a DHCP or BOOTP client on more
than one subnet with fixed addresses, more than one address may be
specified in the
fixed-address parameter, or more than one host statement
may be specified. If client-specific boot parameters must change based on
the network to which the client is attached, then multiple
host statements
should be used. If a client is to be booted using a fixed address if it’s
possible, but should be allocated a dynamic address otherwise, then a
host
statement must be specified without a fixed-address clause. hostname should
be a name identifying the host. If a hostname option is not specified for the
host, hostname is used. Host declarations are matched to actual DHCP or
BOOTP clients by matching the dhcp-client-identifier option specified in the
host declaration to the one supplied by the client, or, if the host declaration
or the client does not provide a dhcp-client-identifier option, by matching the
hardware parameter in the host declaration to the network hardware
address supplied by the client. BOOTP clients do not normally provide a
dhcp-client-identifie r, so the hardware address must be used for all clients
that may boot using the BOOTP protocol.
Group
group { [ parameters ] [ declarations ] }
The group statement is used simply to apply one or more parameters to a
group of declarations.
It can be used to group hosts, shared networks, subnets, or even other
groups.
8.4.3 ALLOW and DENY
The
allow and deny statements can be used to control the behaviour of the
DHCP server in response to various sorts of requests.
unknown-clients
allow unknown-clients;