How routers reset Privileged passwords

As a network administrator, the security of the router password is a very important thing, but if inadvertently forgotten how to do it? The only way to do that is to reset the password information for the router.

Network-managed switches typically have a "Console" port [1], which is specifically designed to configure and manage the switch. Connecting and configuring the switch through the console port is the step that must be passed to configure and manage the switch. Because other configurations often require an IP address, domain name, or device name to be implemented, and the newly purchased switch is clearly not built with these parameters, the console port is the most common and basic switch management and configuration port.

First of all to prepare a console line to connect the router and control computer, only in close proximity to the router rather than remote login to achieve its privileged password reset, first of all, we have to understand the router register related concepts.

Configuration Register Values and theirmeaning

If you are know the value of the your configuration register, you can determine itsmeaning. For information on the meaning your configuration register setting,including potential issues and fixes, collect the OU Tput of the Showversion command, or the show Tech-support Command,and input into the Output interpreter (registered Custo MERS only) tool. In the order of "Use Output Interpreter" (registered customers only), you are must be a registered Customer,be logged in, and have JavaScript enabled.
This table contains some common the settings which are valid on most platforms.
Note:check the appropriate hardware installation Guide to verifythat the configuration register can is used before you CH Ange the configurationregister on your router to one of the values in this table.

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In short, it is to keep in mind that several commonly used:

0X2102: Standard default values

0x2142: Starting from flash, but not using the configuration file in NVRAM (for password recovery)

0X2101: Booting from boot RAM, applied to update system files

0x2141: Starting from boot RAM, but not using the configuration file in NVRAM

For the siege router password, the specific steps are as follows:

Deliberately set up complex passwords for simulation experiments

router>en

Router#configure Terminal

Enter configuration commands, one perline. End With cntl/z.

Router (config) #enable secret 1234qwer

Enter invalid password three times to exit

router>en

Password:

Password:

Password:

% Bad Secrets

Turn off the actual power button on the router and reboot and hold the Ctrl+break key in 60 seconds to enter the option

Self decompressing the Image:

##############################

Monitor:command "boot" aborteddue to user interrupt

Starting from flash, but not using the configuration file in NVRAM (for password recovery)

Rommon 1 > Confreg 0x2142

Rommon 2 > Reset//can realize computer reboot

Direct access to privileged mode, no password restrictions

router>en

Router#configure Terminal

Enter configuration commands, one perline. End With cntl/z.

Router (config) #config-register 0x2102//restore Default boot state

Router (config) #enable secret 123//set a new password

Router (config) #exit

router#

%sys-5-config_i:configured from console Byconsole

Save the configuration file that is now running in the startup file so that changes to the password are valid the next time you start

Router#copy Running-configstartup-config

Destination filename [startup-config]?

Building configuration ...

[OK]

Router#reboot

After the restart after the experiment can be found to have realized the reset of the password, in the real system operation, maintenance of the normal operation of the router password is very important, so the router switches and other devices should be kept in a safe position.