What is Confreg in a Cisco router?
Configuration Register is a special 16 bits value that can be configured in Cisco routers. It is mainly used in three cases; To determine how the router boots. To determine boot options.
How do I change the register value of a Cisco switch?
To change the configuration register settings from the Cisco IOS CLI, complete the following steps:
- Connect a terminal or PC to the router console port.
- Configure your terminal or terminal emulation software for 9600 baud (default), 8 data bits, no parity, and 2 stop bits.
- Power on the router.
How do I find my config register?
To view the current setting of the configuration register, establish a console or Telnet session with the router. Issue the show version command, and input the contents into the Output Interpreter.
What is the purpose of configuration register?
The Configuration Register. When a router starts up it needs to know which software to load and which configuration file to use. The way it determines these two things is by looking at its configuration register setting and its startup configuration in nonvolatile RAM (NVRAM).
What does the configuration register values of 0x2142 instruct the router to do?
For the configuration register value 0x2142, a router will load the IOS from the flash memory, ignore the start- up configuration in NVRAM, and provide a prompt for initial configuration dialog. If no operating system is found, then the router will boot to ROMMON.
How do I change the registration value?
To change the value of a register
- In the Registers window, use the TAB key or the mouse to move the insertion point to the value you want to change. When you start to type, the cursor must be located in front of the value you want to overwrite.
- Type the new value. Caution.
How do you switch Rommon mode?
If the switch continuously reboots, press Control-C to prevent autoboot and to get into ROMmon mode.
How do you break into Cisco Rommon?
Press break on the terminal keyboard within 1 minute of power up in order to the router into ROMmon. Enter in confreg 0x2142 at the rommon 1> prompot in order to boot the from Flash. Type reset at the rommon 2> prompt. Type no after each setup question or press Ctrl+C to bypass all questions.
What is 0x2142 config register?
Configuration register is 0x2142. In this example, the configuration register shows 0x2142. The router bypasses the startup configuration stored in NVRAM during its boot sequence. This feature is normally used during a password recovery procedure.
What is the default configuration register for a Cisco switch or router?
2102 is the default setting that tells the router to use a console speed of 9600 baud and to load the Cisco IOS image from flash memory.
How do I boot in Rommon?
To manually boot into the ROMmon mode, you will need to reboot the device and break the boot sequence. Pressing the Ctrl+Break key combination during boot usually does this.
How do I boot in ROMmon?