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