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Reset a Cisco Router to Factory Default Settings

Cisco - Reset a Cisco Router to Factory Default Settings

Document ID: 46509

Updated: Aug 02, 2006

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Introduction

This document describes how to restore a Cisco router to its original factory default settings.

Prerequisites

Requirements

In order to perform the procedures described in this document, you must have "enable" (also known as "privileged EXEC") access on the router.

Router# - Privileged EXEC mode

Components Used

This document is not restricted to specific software and hardware versions.

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Conventions

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

Instructions to Reset a Cisco Router Back to Factory Defaults

There are two main methods to return a Cisco router to its original factory defaults. These two methods are described below.

Method 1

This method uses the config-register 0x2102 command in global configuration mode.

  1. Check the configuration register on the router by issuing the show version command.

    The configuration register setting is displayed in the last line of the show version command output and should be set to 0x2102. If this is not the case, enter the config-register 0x2102 command once in global configuration mode.

    router#configure terminal
    router(config)#config-register 0x2102
    router(config)#end
    router#

    If the show version command is issued again, the same line in the command output will have '(will be 0x2102 at next reload)' appended to the current register setting.

  2. Erase the current start-up configuration on the router with the write erase command.

  3. Reload the router with the reload command. When prompted to save the configuration, DO NOT save.

    router#reload
    System configuration has been modified. Save? [yes/no]: n
    Proceed with reload? [confirm]

    Once the router reloads, the System Configuration Dialog appears.

             --- System Configuration Dialog ---
    Would you like to enter the initial configuration dialog? [yes/no]:

    The router is now reset to the original factory defaults.

Method 2

This method uses the config-register 0x2142 command in global configuration mode.

  1. Enter the config-register 0x2142 command in global configuration mode.

    router(config)#config-register 0x2142
    

    This causes the router to ignore the start-up configuration on the next reload. If a show version is issued, the last line in the command output will have '(will be 0x2142 at next reload)' appended to the current configuration register setting.

  2. Reload the router using the reload command in enable mode. It is not necessary to save when prompted to save the system configuration.

    router#reload
    System configuration has been modified. Save? [yes/no]: n
    Proceed with reload? [confirm]

    After the router has reloaded, the System Configuration Dialog appears.

  3. Enter no to the question "Would you like to enter initial configuration dialog?"

  4. Change the configuration register setting to 0x2102 by entering the config-register 0x2102 command once in global configuration mode.

  5. Issue the write memory command in enable mode to overwrite the existing start-up configuration with the current running configuration.

  6. Reload the router with the reload command in enable mode.

    Once the router reloads, the System configuration Dialog appears.

             --- System Configuration Dialog ---
    Would you like to enter the initial configuration dialog? [yes/no]:
    

    The router is now reset to the original factory defaults.

Note: The configurations below are stored in ROMMON, and cannot be reset to Factory Default Settings by the write erase or config-register 0x2142 commands.

  • warm-reboot

  • memory-size iomem <not default>

Verify

This section provides information you can use to verify that your router has been returned to the factory defaults.

Certain show commands are supported by the Output Interpreter Tool (registered customers only) , which allows you to view an analysis of show command output.

  • show running-config—Used to verify that the previous running configuration has been erased. The user should be left with a skeleton configuration. For example, there should be no IP addresses configured under any interface on the router.

  • show version—Used to verify that the configuration register is set to the default value of 0x2102.

Related Information

Updated: Aug 02, 2006
Document ID: 46509