14-2
Catalyst 2360 Switch Software Configuration Guide
OL-19808-01
Chapter 14 Configuring DHCP Features
Understanding DHCP Features
DHCP Server
The DHCP server assigns IP addresses from specified address pools on a switch or router to DHCP
clients and manages them. If the DHCP server cannot give the DHCP client the requested configuration
parameters from its database, it forwards the request to one or more secondary DHCP servers defined
by the network administrator.
DHCP Relay Agent
A DHCP relay agent is a device that forwards DHCP packets between clients and servers. Relay agents
forward requests and replies between clients and servers when they are not on the same physical subnet.
Relay agent forwarding is different from the normal Layer 2 forwarding, in which IP datagrams are
switched transparently between networks. Relay agents receive DHCP messages and generate new
DHCP messages to send on output interfaces.Cisco IOS DHCP Server Database
During the DHCP-based autoconfiguration process, the designated DHCP server uses the Cisco IOS
DHCP server database. It has IP addresses,
address bindings
, and configuration parameters, such as the
boot file.
An address binding is a mapping between an IP address and a MAC address of a host in the Cisco IOS
DHCP server database. You can manually assign the client IP address, or the DHCP server can allocate
an IP address from a DHCP address pool. For more information about manual and automatic address
bindings, see the “Configuring DHCP” chapter of the
Cisco IOS IP Configuration Guide,
Release 12.2
.
Configuring DHCP Features
These sections contain this configuration information:
•
Default DHCP Configuration, page 14-2
•
Configuring the DHCP Server, page 14-3
•
Configuring the DHCP Relay Agent, page 14-3
•
Specifying the Packet Forwarding Address, page 14-3
•
Enabling the Cisco IOS DHCP Server Database, page 14-4
Default DHCP Configuration
shows the default DHCP configuration.
Table 14-1
Default DHCP Configuration
Feature
Default Setting
DHCP server
Enabled in Cisco IOS software, requires
configuration
1
DHCP relay agent
Enabled
2
DHCP packet forwarding address
None configured
Содержание Catalyst 2360
Страница 28: ...xxviii Catalyst 2360 Switch Software Configuration Guide OL 19808 01 Preface ...
Страница 200: ...9 24 Catalyst 2360 Switch Software Configuration Guide OL 19808 01 Chapter 9 Configuring VLANs Configuring VLAN Trunks ...
Страница 388: ...23 18 Catalyst 2360 Switch Software Configuration Guide OL 19808 01 Chapter 23 Configuring SNMP Displaying SNMP Status ...