Most Cisco routers or switches can recover the password without changing the hardware jumpers, but in all cases the router needs to be restarted. Password recovery can only be done by connecting to the router from the console.
When the password of the router is unfortunately forgotten or lost, it can be restored by viewing and changing the password. If it is a new device, you can delete the original settings and start again. Each password recovery method generally has the following basic steps:
do not read the stored value, restart the router to set it, this is sometimes called the test system mode, ROM mode or boot mode.
Restart the system and
enter the management mode (such as you In the test system mode, you can enter without a password)
view, change the password or delete the original settings
reboot after resetting the router
restarting the system
Sometimes the terminal must give a BREAK signal when the password is restored, which requires you to be familiar with the terminal Or how the PC virtual terminal gives this signal. For example: Alt+B can generate a BREAK signal. Press Break or Ctrl+Break on the Windows terminal. You can also define a BREAK function key on the Windows terminal. You can get a BREAK signal by pressing the function key and select a specific symbol ^$B (Shift 6, Shift 4, and capital letter B) Define one as a BREAK signal.
Recovery method 1:
The relevant equipment that can use this method are:
Cisco 2000 series
. Cisco 2500 series
. Cisco 3000 series
. Cisco 4000 series at 680x0 and Cisco 7000 series running Cisco IOS 10.0 or later in ROM
. Cisco 7000/7010 have to install RP card, you can boot Cisco flash IOS 10.0 software
connected to the console port of the router virtual terminal or PC terminal. Connect the serial port of the PC to the console port of the router with a direct connection without a modem.
Use the show version command to display and record the set value, usually 0x2102 or 0x102. If you can’t get the prompt with the show version command, you can check similar routers to get the set value or try with 0x2102.
Turn off the power of the router, and then turn it
on again . Press the Break key within the first 60 seconds of startup, you will see ">" prompt symbol (no router name), if you do not see the ">" prompt symbol, it means you did not send out the Break signal correctly, then you can check the settings of the terminal or virtual terminal and
enter it under the ">" prompt symbol o/r 0x42 export from Flash memory or input o/r 0x41 to export from ROM. If it has Flash and has not been moved, 0x42 is the best setting, because it is the default value, and 0x41 is used only when Flash is erased or not installed. If you use 0x41, you can view or delete the original settings, but you cannot change the password
. Type i at the ">" prompt, the router will restart and ignore its saved
settings. All questions in the settings will be answered with "no" "
type in the Router> prompt enable, you will enter the Router # prompt the administrative user
to select one of the following three options: View password, type show config
to change the password (in the case of password encryption), for:
a. Enter config mem to copy NVRAM to memory
b. Enter wr term
c. If you have made enable secret xxxx, execute the following command:
enter config term and then type enable secret and press Ctrl+Z
If you have not made enable secret xxxx, then Enter enable password, Press Ctrl+Z
d. Enter write mem to write to the memory; if you want to delete the setting, type write erase
and type config term at the Router# prompt and type
config-register0x2102, or type the value recorded in the second step and
press Ctrl+Z Exit editing
Enter reload at the Router# prompt, you don’t need to do write memory
recovery. Method 2:
The related devices that can use this method are:.
Cisco 1003 series
. Cisco 4500 series
. Cisco 3600 series with IDT Orion processing device
. Cisco 2600 series, including Motorola 860 family of processors
connected to the console port router virtual terminal or a terminal PC
display show version command and the value stored in the setting record, usually 0x102 or 0x2102
Turn off the power of the router, and then turn it
on again . Press the Break key within 60 seconds before starting, you will see the ">" prompt symbol (no router name), if you do not see the ">" prompt symbol, it means you did not send it correctly Break signal, then you can check the settings of the terminal or virtual terminal
Enter confreg
Do you wish to change configuration[y/n] under the "rommon >" prompt symbol ? When prompted, answer y
to all questions in the setting and answer "no" to
all questions and answer n until ignore system config info[y/n]? When prompted, answer the
remaining questions in y and answer n until change boot characteristics[y/n]? When prompted, answer y.
When entering the boot: prompt, type 2 needs to be modified; if the Flash is erased, type 1. If all the Flash is erased, the 4500 router must be returned to the Cisco Service Center for processing. If you use "1", you can view or delete the old settings, and you cannot change the password.
When there is a setting problem, Do you wish to change configuration[y/n]? When prompted, answer no
and enter reset at the rommon> prompt, or restart (power-cycle) 4500 or 7500.
After it restarts, answer no to all settings
. Enter enable at the Router> prompt, and you will enter the management Mode see Router# prompt
Reprinted at: https://blog.51cto.com/ld11235813/594983