Keith Sinclair

← Cisco Reference

Password Recovery Techniques

Introduction

This document explains several password recovery techniques for Cisco routers. You can perform password recovery on most platforms without changing hardware jumpers, but all platforms require the router to be reloaded. Password recovery can only be done from the console port physically attached to the router.

There are three ways to restore enable access to a router when the password is lost. You can VIEW the password, CHANGE the password, or ERASE the configuration and start over as if the box was new.

Each procedure follows these basic steps:

  1. Configure the router to boot up without reading the configuration memory (NVRAM). This is sometimes called the test system mode.
  2. Reboot the system.
  3. Access enable mode (which can be done without a password if you are in test system mode).
  4. VIEW or CHANGE the password, or ERASE the configuration.
  5. Reconfigure the router to boot up and read the NVRAM as it normally does.
  6. Reboot the system.
NOTE: Some password recovery requires that a terminal issues a Break signal; you must be familiar with how your terminal or PC terminal emulator issues this signal. For example, in ProComm, the keys Alt-B will by default generate the Break signal, and in Windows Terminal you press Break or CTRL-Break. Windows Terminal also allows you to define a function key as BREAK. From the terminal window, select Function Keys and define one as break by filling in the characters ^$B (Shift 6, Shift 4, and Capital B).

The following sections contain detailed instructions for specific Cisco routers. Locate your router in the section headings to determine which technique to use.

Technique #1

All Cisco 2000 Series, 2500 Series, 3000 Series, 680x0-Based 4000 Series, 7000 Series Running 10.0 or Later in ROMs, IGS Series Running 9.1 or Later in ROMs

This technique can be used on the 7000 and 7010 only if the router has 10.0 ROMs installed on the RP card. It may be booting Flash 10.0 software, but it needs the actual ROMs on the processor card as well.

  1. Attach a terminal or PC with terminal emulation to the console port of the router.
  2. Type show version and record the setting of the configuration register. It is usually 0x2102 or 0x102.
  3. Power the router down, then up.
  4. Press the Break key on the terminal within 60 seconds of the power up. You will see the > prompt with no router name.
  5. Type o/r 0x42 at the > prompt to boot from Flash or o/r 0x41 to boot from the boot ROMs. If you use 0x41, you can only view or erase the configuration.
  6. Type i at the > prompt. The router will reboot but will ignore its saved configuration.
  7. Answer “no” to all the setup questions.
  8. Type enable at the Router> prompt.
  9. Choose one of these three options:
    • To VIEW the password: type show config
    • To CHANGE the password: type config mem, then wr term, then use enable secret <password> or enable password <password>, then write mem
    • To ERASE the config: type write erase
  10. Type config term at the prompt.
  11. Type config-register 0x2102 (or whatever value you recorded in step 2).
  12. Hit Ctrl-Z to quit from editor.
  13. Type reload at the prompt. You do not need to write memory.

Technique #2

Cisco 1003, 4500, or IDT Orion-Based Routers

  1. Attach a terminal or PC with terminal emulation to the console port of the router.
  2. Type show version and record the setting of the configuration register.
  3. Power the router down, then up.
  4. Press the Break key within 60 seconds. You will see the rommon> prompt.
  5. Type confreg at the rommon> prompt.
  6. Answer “y” to “Do you wish to change configuration[y/n]?”
  7. Answer “n” to all questions until “ignore system config info[y/n]?” — answer “y”.
  8. Answer “n” until “change boot characteristics[y/n]?” — answer “y”.
  9. At the “enter to boot:” prompt, type 2 (or 1 if Flash is erased).
  10. Answer “n” to the configuration summary prompt.
  11. Type reset at the rommon> prompt, or power cycle.
  12. Answer “no” to all Setup questions.
  13. Type enable at the Router> prompt.
  14. Choose VIEW, CHANGE, or ERASE (same steps as Technique #1).
  15. Type config term, then config-register 0x2102.
  16. Hit Ctrl-Z, then type reload.

Technique #3

IGS Routers Running Software Earlier Than 9.1

IGS routers have a bank of DIP switches on the rear panel. If they are running software earlier than 9.1, then these switches are used for password recovery.

  1. Attach a terminal or PC with terminal emulation to the console port.
  2. Power the router down.
  3. Record the settings of the switches on the rear panel.
  4. Set switch 7 ON (or down).
  5. Set switches 0–3 OFF (or up).
  6. Power the router up. It will boot up to the > prompt.
  7. Type b at the > prompt. The router is in test-system mode.
  8. Press return until the Test-System> prompt appears.
  9. Type enable at the prompt.
  10. Choose VIEW, CHANGE, or ERASE (same steps as Technique #1).
  11. Restore the switch setting to those recorded in step 3.
  12. Reboot the router.

Technique #4

CGS, MGS, AGS, AGS+, 70x0 Running ROMs Lower Than 10.0

  1. Attach a terminal or PC with terminal emulation to the console port.
  2. Power the router down.
  3. Remove the processor card (CSC/2 or CSC/3 or CSC/4 on AGS/CGS/MGS, or RP on a 70x0).
  4. Change the hardware register from bit position 0 (or 1) to position 15.
  5. Re-insert the processor card.
  6. Power the router up.
  7. Press b at the > prompt or b flash if you have Flash memory installed.
  8. Press return until the Test-System> prompt appears.
  9. Type enable at the prompt.
  10. Choose VIEW, CHANGE, or ERASE (same steps as Technique #1).
  11. Power the router down.
  12. Remove the processor card and return the jumper on pin 15 to its original position.
  13. Power the router up.

Technique #4A

AGS Running Versions 10.0(5), 10.2(2) and Later

Same as Technique #4, except at step 8 the router will prompt you if you want to build a new config. Answer “no” and you will go into true boot mode with the Router> prompt.

  1. Attach a terminal or PC with terminal emulation to the console port.
  2. Power the router down.
  3. Remove the processor card.
  4. Change the hardware register from bit position 0 (or 1) to position 15.
  5. Re-insert the processor card.
  6. Power the router up.
  7. Press b or b flash at the > prompt.
  8. Answer “no” to the new config prompt to enter boot mode.
  9. Type enable at the prompt.
  10. Choose VIEW, CHANGE, or ERASE (same steps as Technique #1).
  11. Power the router down.
  12. Remove the processor card and return the jumper on pin 15 to its original position.
  13. Power the router up.

Technique #5

500-CS Communication Servers

The password cannot be recovered from the 500-CS since it does not have a console port. Your only option is to erase the configuration.

  1. Power the router off by unplugging it.
  2. Depress and hold the DEFAULT button on the front of the chassis.
  3. Power the router back on.
  4. Watch the OK and LAN LEDs. They will blink on, and then off.
  5. When they blink off (after about 15 seconds), release the DEFAULT button.
  6. In 2–10 minutes, the 500-CS will enter setup mode as if it was factory new.
  7. Configure the router.

You could also recover a password on a 500 by holding the DEFAULT button down for 30–45 seconds. The system will then be in test mode, and you can follow the normal procedure for password recovery.

Technique #6

Cisco 1020

You must call the Cisco TAC to recover Cisco 1020 passwords. The 1020 will issue a password override challenge that can only be interpreted by TAC personnel.

Technique #7 — Catalyst Switches

Catalyst 1200 and 5000

  1. You must be on the console.
  2. Reboot the device.
  3. When you see the password prompt press Enter (null password for 30 seconds).
  4. Type in Enable.
  5. When you see the password prompt press Enter (null password for 30 seconds).
  6. Change the password.

Catalyst 1600

Push and hold the reset button on the switch until the LCD display shows “erasing mgmt passwd”. Release at that point and the switch will reset without a password. This can also be achieved from TrueView.

Catalyst 1800

Look at the left side of the Catalyst 1800 switch. There should be two red switches located side by side inside the left cover. The red switch nearer to the front is the NMI switch. Press the NMI switch 3 times within the first 30 seconds of power-up. This will reset the password back to the default value of “public”.

Catalyst 2600

Press the System Request button to access the System Request Menu, then select Clear NVRAM. This will clear the password but will also reset all configuration parameters to their default values.

Catalyst 3000

  1. Press the sys req button.
  2. Move the arrow key to clear NVRAM.
  3. Press Return.
  4. The box will now reboot, no password required.