How to Clear Switch Configuration
To clear switch configuration you need access to the Cisco Catalyst Switch console through either a physical console or a Telnet connection.
Clear switch configuration
Issue the erase starting-config command in Privileged EXEC mode.
Switch#erase startup-config
Erasing the nvram filesystem will remove all configuration files! Continue? [confirm] [OK] Erase of nvram: complete Switch#
At this stage, the switch configuration is cleared except the VLAN information. VLANs are kept in a seperate file from the startup-config (NVRAM).
Verify the VLAN information Before deletion
Issue the show vlan brief command in Privileged EXEC mode.
Switch#show vlan brief
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Fa0/1, Fa0/2, Fa0/3, Fa0/4
Fa0/5, Fa0/6, Fa0/7, Fa0/8
Fa0/9, Fa0/10, Fa0/11, Fa0/12
Fa0/13, Fa0/14, Fa0/15, Fa0/16
Fa0/17, Fa0/18, Fa0/19, Fa0/20
Fa0/21, Fa0/22, Fa0/23, Fa0/24
Gi0/1, Gi0/2
10 Faculty/Staff active
20 Students active
30 Wireless active
99 Management active
1002 fddi-default act/unsup
1003 token-ring-default act/unsup
1004 fddinet-default act/unsup
1005 trnet-default act/unsup
Switch#
Delete the VLAN information from Flash
Switch#delete flash:vlan.dat
Delete filename [vlan.dat]? Delete flash:vlan.dat? [confirm] Switch#
At the prompt press Enter.
Reload the switch
Do not save at the prompt. Otherwise, the switch reloads with the current running configuration and does not clear the switch configuration.
Switch#reload
System configuration has been modified. Save? [yes/no]: n
Proceed with reload? [confirm]
<output omitted>
Would you like to terminate autoinstall? [yes]: y
--- System Configuration Dialog ---
Would you like to enter the initial configuration dialog? [yes/no]: n
Switch>
After reload check the vlan information
check the VLAN information with the show vlan brief command.
Switch#show vlan brief
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Fa0/1, Fa0/2, Fa0/3, Fa0/4
Fa0/5, Fa0/6, Fa0/7, Fa0/8
Fa0/9, Fa0/10, Fa0/11, Fa0/12
Fa0/13, Fa0/14, Fa0/15, Fa0/16
Fa0/17, Fa0/18, Fa0/19, Fa0/20
Fa0/21, Fa0/22, Fa0/23, Fa0/24
Gi0/1, Gi0/2
1002 fddi-default act/unsup
1003 token-ring-default act/unsup
1004 fddinet-default act/unsup
1005 trnet-default act/unsup
Compiled Thu 19-Jul-07 20:06 by nachen