How to reset password for cisco router and switch

Router:

1. Console port connect to PC COM port.

2. Open the ScecureCTR or other software , e.g. Putty.

3. When loading IOS image ,use Ctrl+C to interrupt the progress to got ROMMON model

(this model is like the grub prompt interface of linux)

 rommon>

4. confreg 0x2142,  This command tell router don’t load startup-config next time

restart 。

5.Restart the router manually,or use reload to restart.

6 Execute the following command when the router on(after IOS image loaded and the

setup process show.enter no to terminate the process.)

enable                                                            enter the privileged EXEC mode

copy start run                                           copy the startup-config to running-config

conf t                                                                enter the configuration  mode

ena sec ****                                                      enable secret set as ****，change the password.

config-register 0x2102                     restore the register value,the value maybe

different,so you better got the value before change to 0x2142 use show version

end or Ctrl+C                                             exit from the configuration mode

copy run start  or  wr                                    save all the config to NVRAM.

 Boot or Reload                boot the IOS or reboot the router.it seems that we

don’t need to restart the router.

 

Switch:

1. Connect the switch RJ-45 console port and the PC’s COM port.

2. launch the remote connect software, e.g. SecureCRT,Putty.

3.Power on the switch device,and press the mode button until the port status LEDs are down.enter the ROMMON model.

flash_init                                                              init the flash file system.

load _helper                       

dir flash:                                                               change the work directory to flash: and display the files.

rename flash:config.txt flash:config.back  rename the configure file name to let the switch can’t find

the  file”config.txt”.

boot                                                                        boot the IOS image and the operation system will can’t

find the configure file. the setup dialog will process.

NO                                                                          enter NO to ignore the dialog

enable                                                                    enter the privileged EXEC mode

rename flash:config.back flash:config.text                restore the file name of the config.txt

copy flash:config.text system:running-config            copy the startup-config to running-config,

conf t                                                                                     enter the configuration mode

ena sec ****                                                                        reset enable password

end                                                                                         exit from the configuration mode

copy run start                                                               save the running-config to flash.(not

NVRAM,it’s different from router)

reload                                                                           reboot the system,but maybe this step is

not necessary

In ALL.the purpose of all the methods used  is to ignore/skip the configuration file.because the password is stored in the configuration file.

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