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This article will explain in detail how to recover the forgotten password of the cisco router. The content of the article is of high quality, so the editor will share it for you as a reference. I hope you will have a certain understanding of the relevant knowledge after reading this article.

It is very common and troublesome for routers to forget their passwords, so we need to recover our passwords at this time. The main steps to recover the password are:

1. Interrupt the router startup ctrl+break key

two。 Change the value of the configuration register to 0x2142

3. Restart the router

4. View the enable password in the saved configuration file

5. Reset enable password

6. Save configuration

7. Change the value of the configuration register to 0x2102

Actual configuration:

Shut down the router and restart:

Self decompressing the p_w_picpath: press the ctrl+ break key when starting the router

# #

Monitor: command "boot" aborted due to user interrupt

The value of rommon 1 > confreg 0x2142 configuration register is 0x2142

Rommon 2 > reset restart the router

Continue with configuration dialog? [yes/no]: n startup-config is no longer loaded

Router#show startup-config to view previous passwords

Router#copy startup-config running-config loads the previous configuration into memory

Router#config t enters global configuration mode

Router (config) # enable password cisco resets the password

Router (config) #

Router#copy running-config startup-config will save the configuration after changing the password.

Destination filename [startup-config]?

Building configuration...

[OK]

Router#Router#show version looks at the value of the configuration register

Configuration register is 0x2142

Router#conf t

Enter configuration commands, one per line. End with CNTL/Z.

Router (config) # conf t

Router (config) # config-register 0x2102 reconfigure register values

Attached: the meaning of register value

0x2102: the interrupt key is blocked during operation, and the router will check the configuration in NVRAM to determine the startup order. If the startup fails, it will start with the default ROM software.

0x2142: used when recovering passwords. Ignore the NVRAM configuration information and enter the initial configuration dialog mode.

The router startup process:

First, after the router is powered on, first run the POST program (Power On Self Test) in ROM to detect the hardware of the router, commonly known as power-on self-test.

Second, the boot program (bootstrap) in ROM is executed immediately after the test is passed, and the startup mode is determined according to the register value (register).

The format of the register value is: 0x21YZ Y column status: 0x210Z loads configuration file from nvram 0x214Z does not load configuration file Z column status from nvram: 0x21Y0 startup prompt from rommon is: > (press Ctrl+Break when the router starts) 0x21Y1 startup prompt from mini ios is: Router (boot) > 0x21Y2 boot prompt from flash: Router >

Two register values we often use: 0x2102 (normal) and 0x2142 (do not read the saved configuration).

Third, if it starts normally, press the bootstrap program to look for the IOS image in Flash. If an IOS image is found, it starts normally after reading. If the IOS image is not found, enter boot mode, that is, Mini IOS startup. In boot mode, you can use IOS; on TFTP or use TFTP/X-modem to refill an IOS for the router. If Mini IOS also fails to start, enter rom monitor mode.

Fourth, after reading the IOS and initializing it successfully, the bootstrap program will have more register values to decide whether to load or not load the startup configuration file. If you choose to load, find the startup configuration file in NVRAM and load it into RAM to become the running configuration file. If you choose not to load or there is no startup configuration file at all, the router enters challenge configuration mode and basically configures the router in a question-and-answer manner.

Fifth, enter the user mode and complete the startup process.

About the cisco router forgot the password how to share here, I hope the above content can be of some help to you, can learn more knowledge. If you think the article is good, you can share it for more people to see.

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