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Catalyst 4500 Series, Catalyst 2948G, Catalyst 2948G-GE-TX, and Catalyst 2980G Switches Software Configuration Guide—Release 8.2GLX
78-15908-01
Chapter 3 Configuring the Switch IP Address and Default Gateway
Using DHCP or RARP to Obtain an IP Address Configuration
Using DHCP or RARP to Obtain an IP Address Configuration
Note
For complete information on how the switch uses DHCP or RARP to obtain its IP configuration, see the
“Understanding How Automatic IP Configuration Works” section on page 3-2
.
To use DHCP or RARP to obtain an IP address for the switch, perform this task:
This example shows the switch broadcasting a DHCP request, receiving a DHCP offer, and configuring
the IP address and other IP parameters according to the contents of the DHCP offer:
Console> (enable) Sending RARP request with address 00:90:0c:5a:8f:ff
Sending DHCP packet with address: 00:90:0c:5a:8f:ff
dhcpoffer
Sending DHCP packet with address: 00:90:0c:5a:8f:ff
Timezone set to '', offset from UTC is 7 hours 58 minutes
Timezone set to '', offset from UTC is 7 hours 58 minutes
172.16.30.32 added to DNS server table as primary server.
172.16.31.32 added to DNS server table as backup server.
172.16.32.32 added to DNS server table as backup server.
NTP server 172.16.25.253 added
NTP server 172.16.25.252 added
%MGMT-5-DHCP_S:Assigned IP address 172.20.25.244 from DHCP Server 172.20.25.254
Console> (enable) show interface
sl0: flags=51<UP,POINTOPOINT,RUNNING>
slip 0.0.0.0 dest 0.0.0.0
sc0: flags=63<UP,BROADCAST,RUNNING>
vlan 1 inet 172.20.25.244 netmask 255.255.255.0 broadcast 172.20.25.255
dhcp server: 172.20.25.254
Console>
Task
Command
Step 1
Make sure that there is a DHCP, BOOTP, or RARP server on the
network.
—
Step 2
Obtain the last address in the MAC address range for module 1
(the supervisor engine). This address is displayed under the
MAC-Address(es) heading. (With DHCP, this step is necessary
only if using the manual allocation method.)
show module
Step 3
Add an entry for each switch in the DHCP, BOOTP, or RARP
server configuration, mapping the MAC address of the switch to
the IP configuration information for the switch. (With DHCP,
this step is necessary only with the manual or automatic
allocation methods.)
—
Step 4
Set the sc0 interface IP address to 0.0.0.0.
set interface sc0 0.0.0.0
Step 5
Reset the switch. The switch broadcasts DHCP and RARP
requests only when the switch boots up.
reset system
Step 6
When the switch reboots, confirm that the sc0 interface IP
address, subnet mask, and broadcast address are set correctly.
show interface
Step 7
For DHCP, confirm that other options (such as the default
gateway address) are set correctly.
show ip route