3Com Switch 8807, Configuration Manual

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684 C
HAPTER
57: DHCP C
ONFIGURATION
DHCP provide a framework about how to set a host on a TCP/IP network. DHCP is
derived from BOOTP, and possesses more function such as automatic allocation of
reusable network addresses and additional configuration options. DHCP can act as
a BOOTP relay agent, so a DHCP user and a BOOTP user can interact with each
other.
The message format of DHCP is based on the message format of BOOTP, so that it
can work as a relay agent and allow the coordination (interoperability) between
existing BOOTP clients and the DHCP server. The use of a BOOTP relay agent
makes it unnecessary to employ a DHCP server for every physical network
segment.
DHCP defers from BOOTP in that:
■
DHCP defines a mechanism through which a client can be allocated with a
network address valid for a fixed lease period. In addition, it allows for
continuous reallocation of network addresses to different clients.
■
DHCP provides a mechanism through which a client is allowed to obtain all IP
configuration parameter for subsequent operations.
Configuring General
DHCP
General DHCP configuration refers to those that are applicable to both DHCP
server and DHCP relay.
The following sections describe the general DHCP configuration tasks:
■
“Enabling/Disabling DHCP Service”
■
“Configuring Processing Method of DHCP Packets”
■
“Enabling/Disabling Fake DHCP Server Detection”
Enabling/Disabling
DHCP Service
For both DHCP server and DHCP relay, you must enable the DHCP service first
before performing other DHCP configurations. The other related DHCP
configurations take effect only after the DHCP service is enabled.
Perform the following configuration in system view.
DHCP service is disabled by default.
Configuring Processing
Method of DHCP Packets
You can perform the configurations listed in the following tables on your switch.
After that, the switch processes the DHCP packets it received from DHCP clients in
the methods you have configured.
Perform the following configuration in VLAN interface view to configure the
processing method of DHCP packets for current VLAN interface.
Table 618 Enable/Disable DHCP service
Operation Command
Enable DHCP service dhcp enable
Disable DHCP service undo dhcp enable