Cisco Router Password Recovery Procedure.pdf

Cisco − Password Recovery Procedure for the Cisco 2000, 2500, 3000, 4000, AccessPro, 7000 (RP), AGS, IGS, STS−10x

Table of Contents

Password Recovery Procedure for the Cisco 2000, 2500, 3000, 4000, AccessPro, 7000 (RP), AGS,

IGS, STS−10x. ....................................................................................................................................................1

Document ID: 12722.. ..............................................................................................................................1

Introduction. .........................................................................................................................................................1

Prerequisites. ........................................................................................................................................................1

Requirements. .........................................................................................................................................1

Components Used. ..................................................................................................................................1

Conventions. ...........................................................................................................................................2

Step−by−Step Procedure. .....................................................................................................................................2

Sample Output. .......................................................................................................................................3

Example for Enable Password Recovery. ...............................................................................................6

Example for Password Replacement. .....................................................................................................7

NetPro Discussion Forums − Featured Conversations. .....................................................................................10

Related Information. ..........................................................................................................................................10

Password Recovery Procedure for the Cisco 2000,

2500, 3000, 4000, AccessPro, 7000 (RP), AGS, IGS,

STS−10x

Document ID: 12722

Introduction

Prerequisites

Requirements

Components Used

Conventions

Step−by−Step Procedure

Sample Output

Example for Enable Password Recovery

Example for Password Replacement

NetPro Discussion Forums − Featured Conversations

Related Information

Introduction

This document describes the procedure to recover an enable password or enable secret password . These

passwords are used to protect access to privileged EXEC and configuration modes. The enable password can

be recovered. However, the enable secret password is encrypted, and can only be replaced with a new

password, for which this document provides the procedure.

The enable password or the enable−secret password is stored in the startup−configuration file in the

nonvolatile RAM (NVRAM). The password recovery procedure involves booting the router while ignoring

the startup−configuration file in the NVRAM. To achieve this, set the 6th bit in the configuration register. The

router then boots with the default configuration and all the interfaces in "shutdown" state. Since the default

configuration does not have a password, anyone can now enter the enable mode on the router. To get back the

original configuration of the router, the startup−configuration file can be copied into the router memory. If

you are already in the enable mode, you can either view or change the enable password , but can only change

the enable secret password , because it is always encrypted in the show commands. This document details

this procedure.

Prerequisites

Requirements

Before you use the information in this document, see Possible Key Combinations for Break Sequence During

Password Recovery. You should also be aware of concepts related to loading the Cisco IOS® Software such

as, ROM monitor (ROMmon), bootflash, and the configuration register values.

Components Used

The information in this document is based on these software and hardware versions:

Cisco IOS Software Release 12.2(10b).

Cisco − Password Recovery Procedure for the Cisco 2000, 2500, 3000, 4000, AccessPro, 7000 (RP), AGS, IGS, STS−10x

Cisco 2500 Series Router.

Note: Although a Cisco 2500 Series Router is used as an example in this document, the password

recovery procedure presented here applies to all the platforms listed above.

Conventions

For more information on document conventions, see the Cisco Technical Tips Conventions.

Step−by−Step Procedure

Complete these steps to recover a lost or forgotten password:

Attach a terminal or PC with terminal emulation to the console port of the router. Use these terminal

settings:

9600 baud rate

No parity

8 data bits

1 stop bit

No flow control

The required console cable specifications are described in the Cabling Guide for RJ−45 Console and

AUX Ports (Cisco 1000 Series, 2500 Series, and AS5100).

If you still have access to the router, enter the show version command, and record the setting of the

configuration register; it is usually 0x2102 or 0x102.

For a sample output of a show version command, see the Sample Output section.

If you do not have access to the router (because of a lost login or TACACS password), you can safely

assume that your configuration register is set to 0x2102.

Note: Password recovery procedures cannot be done through telnet connections.

Turn the power switch of the router off, and then turn it back on.

Send a break sequence from the terminal keyboard within 60 seconds of the power−up to put the

router into ROMmon. The break sequence depends on your Operating System or Terminal Emulator.

See Standard Break Key Sequence Combinations During Password Recovery for different key

combinations.

Type o and press ENTER at the > prompt, and record the current value of the configuration register

(usually 0x2102, or 0x102):

> o

!−−− Shows the configuration register option settings.

Configuration register = 0x2102 at last boot

Bit# Configuration register option settings:

15 Diagnostic mode disabled

!−−− Output supressed.

Type o/r 0x2142 and press ENTER at the > prompt to boot from Flash without loading the

Cisco − Password Recovery Procedure for the Cisco 2000, 2500, 3000, 4000, AccessPro, 7000 (RP), AGS, IGS, STS−10x

configuration.

Type i at the > prompt and press ENTER.

The router reboots, but ignores its saved configuration.

Type no after each setup question or press CTRL + C to skip the initial setup procedure.

Type enable at the Router> prompt.

You will be in enable mode, and see the Router# prompt.

Type configure memory or copy startup−config running−config to copy the NVRAM into

memory. Do not type write memory or copy running startup−config .

10.

Type write terminal or show running−config .

The show running−config and write terminal commands show the configuration of the router. In

this configuration you see under all the interfaces the shutdown command, which means all interfaces

are currently shutdown. Also, you can see the passwords either in encrypted or unencrypted format.

11.

Type configure terminal and make the changes.

The prompt is now:

hostname(config)#

12.

Type enable secret < password > to change the enable secret password , for example..

13.

Issue the no shutdown command on every interface that is used. If you issue a show ip interface

brief command after you exit configuration mode, every interface that you want to use should be "up

up".

14.

Type config−register 0x2102 , or the value you recorded in step 4.

This causes the router to load the Cisco IOS software from the Flash with the configuration from

NVRAM at the next reload.

15.

Press CTRL + Z to leave the configuration mode.

The prompt is now:

hostname#

16.

Type write memory or copy running−config startup−config to commit the changes.

17.

Type Reload to restart the router with the Cisco IOS software booting from the Flash.

Sample Output

The example below presents an actual password recovery procedure. We created this example using a Cisco

2500 series router. Even if you do not use a Cisco 2500, the example shown here will be almost similar to

what you experience on your product.

Router> enable

Password:

% Bad secrets

Router> show version

Cisco Internetwork Operating System Software

IOS (tm) 2500 Software (C2500−JS−L), Version 12.2(24a)

RELEASE SOFTWARE (fc3)

Cisco − Password Recovery Procedure for the Cisco 2000, 2500, 3000, 4000, AccessPro, 7000 (RP), AGS, IGS, STS−10x

Compiled Fri 28−May−04 19:30 by pwade

Image text−base: 0x0306C4E0, data−base: 0x00001000

ROM: System Bootstrap, Version 11.0(10c), RELEASE SOFTWARE

BOOTFLASH: 3000 Bootstrap Software (IGS−BOOT−R), Version 11.0(10c),

RELEASE SOFTWARE (fc1)Router uptime is 5 minutes

System returned to ROM by power−on

System image file is "flash:/c2500−js−l.122−24a.bin"

cisco 2500 (68030) processor (revision D) with 14336K/2048K bytes of memory.

Processor board ID 02315272, with hardware revision 00000000

Bridging software.

X.25 software, Version 3.0.0.

TN3270 Emulation software.

1 Ethernet/IEEE 802.3 interface(s)

1 Token Ring/IEEE 802.5 interface(s)

2 Serial network interface(s)

32K bytes of non−volatile configuration memory.

16384K bytes of processor board System flash (Read ONLY)

Configuration register is 0x2102

!−−− This is the current value of the configuration register.

Router>

!−−− The router was just power cycled and during bootup a

!−−− break sequence was sent to the router.

System Bootstrap, Version 11.0(10c), SOFTWARE

2500 processor with 16384 Kbytes of main memory

Abort at 0x10EA83C (PC)

> o

Configuration register = 0x2102 at last boot

!−−− You can also view the configuration register settings value

!−−− by issuing the command "o" in the ROMmon prompt.

Bit# Configuration register option settings:

15 Diagnostic mode disabled

14 IP broadcasts do not have network numbers

13 Boot default ROM software if network boot fails

12−11 Console speed is 9600 baud

10 IP broadcasts with ones

08 Break disabled

07 OEM disabled

06 Ignore configuration disabled

03−00 Boot file is cisco2−2500 (or 'boot system' command)

Cisco − Password Recovery Procedure for the Cisco 2000, 2500, 3000, 4000, AccessPro, 7000 (RP), AGS, IGS, STS−10x

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