ccna 200 301 volume 1 pdf

ccna 200 301 volume 1 pdf.Suppose you are sitting at your desk trying to log in to the router using secureShell (SSH) or remotely, but you cannot log in, or you can log in to user mode but cannot enter privileged mode (enable mode) because you have forgotten your privileged password. This requires a recovery, or at least a password reset, before you can log in to the router to change the configuration. How do I do that?If you are right next to the router, you can use the method provided by Cisco for resetting the router password. By accessing the router console as well as switching the router on and off, anyone will be able to reset the password to any value at the router.The exact details vary depending on the model of the router. If you visit www.cisco.com "password recovery", then the main password recovery page should be found in the first few results of the query page. This page has detailed instructions for password recovery (actually resetting your password), and it works for almost all models of Cisco products. Tip: Cisco tends to mention the topic of the password recovery section, but you don't actually need to recover or know the forgotten password. You can instead set a new value. : TheThe general idea behind Cisco password recovery/reset416 Chapter 20 Managing IOS FilesAlthough the details will vary from model to model, all password recovery procedures follow roughly the same principles. First, the ultimate goal of this process is to cause the router to boot the IOS, ignoring the startup-config file. Of course, this startup-config file holds all the passwords. Once the router ignores the initial configuration and starts booting directly, it is possible to log into the console and reconfigure all passwords without password restrictions.Cisco defines a specific configuration register bit one that, if it is set to a binary 1, tells the router to skip the startup-config file and boot directly the next time it loads. To set this value, you can change the default configuration register value of 0x2102 to 0x21420Unfortunately, the privileged password (enablepassword) must be remembered to enter this mode configuration register value. When the password needs to be recovered, you obviously don't remember it anymore, so how can you change the configuration register? The solution is to use ROMMON mode.ROMMON is capable of issuing commands, including commands to set the configuration registers. Compared to I0S, ROMMON contains a relatively small and different set of CLI commands. These commands may even vary depending on the router model. However, each router's ROMMON software supports some of these commands, usually config commands that can set configuration registers. For example, the ROMMON command confreg0x2142 will set the correct bit value to tell the router to ignore the boot configuration file on reload.So, how do you get the router into ROMMON mode? Older routers support the legacy option of using the break key on the console, while newer routers may only require the flash memory to be deleted, as follows. Older routers: On the console, use the terminal emulator to enter commands at the CLI. Then turn the router off and then back on again later. Within the first 30 seconds, press the "break" key on the keyboard. This tells the router to interrupt the normal boot sequence and load the ROMMON.