What Happens If You Change The Configuration Register To 0x2142 Then Reset Router
Configuration Register
What is Configuration Register?
Configuration Register is a special xvi bits value that can be configured in Cisco routers. It is mainly used in three cases;
- To determine how the router boots
- To determine kick options
- To gear up panel speed
During the boot, router checks its software and the configuration files. To determine these files, router firstly bank check Configuration Register. According to its value, router determines what to practise.
Configuration Register Configuration is particularly used for Router Password Recovery. So, what are the values of this special number?
Configuration Annals 0x2102
The default value of Config Register is 0x2102. With Configuration Annals 0x2102 value, the router boots from NVRAM and the normal router precedures works. The configuration stored in NVRAM is the startup configuration. So, if nosotros need to featherbed this configuration, we tin can change the default value. Especially during Router Password Recovery, this unproblematic configuration is washed.
We can cheque this value on Cisco routers with "prove version" control. At the output of "show version" control, Configuration Register value will be at the bottom.
Router# testify version
Cisco IOS Software, C800 Software (C800-UNIVERSALK9-K), Version 15.two(four)M4, RELEASE SOFTWARE (fc2)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2013 by Cisco Systems, Inc.
Compiled Thu 20-Jun-thirteen sixteen:14 by mnguyen
ROM: Organisation Bootstrap, Version 15.2(2r)T, RELEASE SOFTWARE (fc1)
Router uptime is 35 minutes, xiv seconds
System returned to ROM by power-on
System image file is "flash:c800-universalk9-mz.SPA.152-4.M4.bin"
…
Configuration annals is 0x2102
Config Annals 0x2142
To bypass NVRAM configuration, in other words, to bypass showtime-upward configurataion, we can alter Config Register value. Here, the new value that we will set will exist Configuration Register 0x2142.
How to Change Configuration Register?
There are two way to alter Config Annals on a router. This can be done both in Rommon mode and in configuration manner.
In Rommon mode, it tin be modify with "confreg" command. Beneath, we are changing Configuration Annals as 0x2142.
rommon > confreg 0x2142
After this configurationi we should reset the router to employ this new value,or to strength the router kick through this config register.
The other way is configuring on configuration way with "config- annals" command.
Router# configure final
Router(config)# config-register 0x2142
After configuration, you tin can check the ne value and be sure virtually the value.
Router# prove version
Cisco IOS Software, C800 Software (C800-UNIVERSALK9-One thousand), Version 15.2(four)M4, RELEASE SOFTWARE (fc2)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2013 past Cisco Systems, Inc.
Compiled Thu 20-Jun-13 16:xiv past mnguyen
ROM: Arrangement Bootstrap, Version fifteen.ii(2r)T, RELEASE SOFTWARE (fc1)
Router uptime is 35 minutes, 14 seconds
System returned to ROM by power-on
Organisation image file is "flash:c800-universalk9-mz.SPA.152-four.M4.bin"
Configuration register is 0x2102 (will be 0x2142 at next reload)
Again, we should reload the router for the new config register to take issue.
Router# reload
System configuration has been modified. Save? [yes/no]: n
Proceed with reload? [confirm]
You lot can observe the detailed information about Config Register on Cisco Page.
What Happens If You Change The Configuration Register To 0x2142 Then Reset Router,
Source: https://ipcisco.com/lesson/configuration-register/
Posted by: fordambateractly.blogspot.com
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