Specifications

4-7
Catalyst 2970 Switch Software Configuration Guide
78-15462-03
Chapter 4 Assigning the Switch IP Address and Default Gateway
Assigning Switch Information
For example, in Figure 4-2, configure the router interfaces as follows:
On interface 10.0.0.2:
router(config-if)# ip helper-address 20.0.0.2
router(config-if)# ip helper-address 20.0.0.3
router(config-if)# ip helper-address 20.0.0.4
On interface 20.0.0.1
router(config-if)# ip helper-address 10.0.0.1
Figure 4-2 Relay Device Used in Autoconfiguration
Obtaining Configuration Files
Depending on the availability of the IP address and the configuration filename in the DHCP reserved
lease, the switch obtains its configuration information in these ways:
• The IP address and the configuration filename is reserved for the switch and provided in the DHCP
reply (one-file read method).
The switch receives its IP address, subnet mask, TFTP server address, and the configuration
filename from the DHCP server or the DHCP server feature running on your switch. The switch
sends a unicast message to the TFTP server to retrieve the named configuration file from the base
directory of the server, and upon receipt, completes its boot-up process.
• The IP address and the configuration filename is reserved for the switch, but the TFTP server
address is not provided in the DHCP reply (one-file read method).
The switch receives its IP address, subnet mask, and the configuration filename from the DHCP
server, or the DHCP server feature running on your switch. The switch sends a broadcast message
to a TFTP server to retrieve the named configuration file from the base directory of the server, and
upon receipt, completes its boot-up process.
• Only the IP address is reserved for the switch and provided in the DHCP reply. The configuration
filename is not provided (two-file read method).
The switch receives its IP address, subnet mask, and the TFTP server address from the DHCP server
or the DHCP server feature running on your switch. The switch sends a unicast message to the TFTP
server to retrieve the network-confg or cisconet.cfg default configuration file. (If the network-confg
file cannot be read, the switch reads the cisconet.cfg file.)
Switch
(DHCP client)
Cisco router
(Relay)
49068
DHCP server TFTP server DNS server
20.0.0.2 20.0.0.3
20.0.0.1
10.0.0.2
10.0.0.1
20.0.0.4