100-490 - Cisco Certified Technician Routing & Switching (RSTECH)

The configuration register on Cisco devices controls how the device boots up. By changing the configuration register to 0x2142, you instruct the router to bypass the startup configuration file stored in NVRAM. This is crucial in the password recovery process because the passwords are stored in this configuration file.

Procedure for Password Recovery:

1.Break the boot sequence: Power cycle the router (turn off/on). During the boot process, send a "Break" signal to get into ROMmon mode.

2.Change the configuration register: In ROMmon mode, type confreg 0x2142 and reload the router.

3.Boot without startup-config: The router will boot up, ignoring the saved startup configuration, allowing you to enter privileged EXEC mode without a password.

4.Change the password: Access configuration mode (configure terminal), and change the passwords as needed (enable password, enable secret, etc.).

5.Reset the configuration register: Set the configuration register back to its original value (usually 0x2102).

6.Save changes: Save the new configuration with copy running-config startup-config.

USB thumb drives (also called flash drives) serve several practical purposes in networking:

• File Transfer:They are excellent for transferring Cisco router or switch configuration files between the device and a PC. This allows you to back up configurations, easily restore configurations, or work with them offline.
• IOS Image Storage:USB thumb drives are convenient for storing and transferring Cisco IOS images, especially when you need to upgrade or recover network devices.

Why other options are incorrect:

• to save the system log:While you might temporarily store log files on a USB drive, routers and switches generally utilize internal memory or a remote syslog server for logging purposes.
• to save router hardware information:Hardware inventory information obtained from commands likeshow inventoryis often copied and pasted to text files, which can then be stored on a USB drive. However, the drive itself doesn't directly save or store this hardware information.
• to increase system memory:USB drives are not designed to act as additional system memory (RAM) for a router or switch.

Microsoft Notepad is the preferred text editor for working with Cisco configuration files and other simple text documents for several reasons:

• Plain Text Focus:Notepad is designed specifically for plain text editing. It does not add any formatting, hidden characters, or metadata that could interfere with the configuration file's structure.
• Cisco Syntax Compatibility:Cisco configurations rely on specific syntax and spacing. Notepad preserves these elements accurately.
• Universality:Notepad is a basic text editor included in all versions of Windows, ensuring accessibility and eliminating the need for additional software.

Why other options are not ideal:

• Microsoft Word:Word is a word processor and includes formatting, fonts, and other features that are not compatible with Cisco configuration files. This formatting can corrupt the configuration.
• Microsoft Access:Access is a database management system, not suited for text file editing.
• Microsoft Excel:Excel is a spreadsheet application and adds its own structure and formatting that conflicts with configuration file formats.