How to solve the problem of Cisco router forgetting password

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In some enterprise networks, there are usually some human factors or other factors that cause the router‘s password to be forgotten. At this time, the administrator is required to restore or change the router‘s password one by one. How to solve the problem of Cisco switch forgetting password To solve this problem, let‘s take a look at the solution of Cisco router forgetting password.
First of all, understand that the password of the router is stored in the startup config. To bypass the configuration of startup config during startup, you need to press and hold the CTRL + break key on the computer to interrupt the loading of IOS when restarting the router,
When the router is introduced into ROM monitor mode, the value of configuration register is changed from 0x2102 to 0x2142, which means that the configuration of startup config is ignored during startup.
I. restart the router
Hold down the CTRL + break key and wait for the router to restart.
Second, modify the value of the configuration register.
　　router(config)#confreg 0x2142
　　router(config)#reset
3. Modify the value of the configuration register and restart
Router (config) # reload Cisco restart
4. After entering the configuration mode for the first time, manually load the configuration file back
　　router#copy startup-config running-config
5. Then use the command show run to check which passwords are configured in the router and modify them one by one
6. Modify the value of the register
　　router(config)#config-register 0x2102
Router (config) ා exit returns to the previous mode
Router # copy running config startup config save configuration at last (equivalent command write)
Note: why change the value of configuration register from 0x2102 to 0x2142?
Because X represents hexadecimal, the conversion from 2102 to hexadecimal is 0010.0001.0000.0010, and the seventh bit from the right can control the order of router startup.
If the bit is 0, it indicates the configuration of running startup config at startup; If the bit is 1, it means that the configuration of startup config is bypassed and the setup mode is entered.
By conversion, if the number of the bit is 1, the value of the configuration register is 0x2142.