How to Reset a Cisco Router to Factory Default Settings

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

First Method:

First 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 0×2102. If not, enter the config-register 0×2102 command once in Router global configuration mode.

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

Now check once again the configuration register value by issuing the show version. The same line in the command output will have “will be 0×2102 at next reload” appended to the current register setting, It means configuration register will set to 0×2102 after next reload.

Next erase the current start-up configuration on the Router issuing the write erase command, 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 reload completes, the System initial Configuration Dialog appears. It means the Router is reset to the original factory defaults.

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

Second Method:

This method uses the configuration register value 0×2142 to reset a Router to factory default settings. Enter the config-register 0×2142 command in global configuration mode.

Router(config)#config-register 0x2142

If a show version is issued, the last line in the command output will have ‘(will be 0×2142 at next reload)‘ appended to the current configuration register setting. This causes the Router to ignore the start-up configuration on the next reload.Reload the Router using the reloadcommand 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 initial Configuration Dialog appears. Enter no to the question “Would you like to enter initial configuration dialog?” and Change the configuration register setting to 0×2102 by entering the config-register 0×2102 command once in global configuration mode.

Router>en
Password:
Router#config terminal
Router(config)#config-register 0x2102

Now issue the write memory command in privilege mode to overwrite the existing start-up configuration with the current running configuration and reload the router with the reload command in enable mode.

Router#write memory
Router#reload

Once the router reloads, the System initial configuration Dialog appears. It means the Router is reset to the original factory defaults.

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