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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:

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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.

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DHCP provides a mechanism through which a client is allowed to obtain all IP 
configuration parameter for subsequent operations.

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:

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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.

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

Enable DHCP service 

dhcp enable 

Disable DHCP service