tailieunhanh - CCNA 1 and 2 Companion Guide, Revised (Cisco Networking Academy Program) part 65

Cisco Networking Academy Program CCNA 1 and 2 Companion Guide, Revised part 65 is the Cisco approved textbook to use alongside version of the Cisco Networking Academy Program CCNA 1 and CCNA 2 web-based courses. The topics covered provide you with the necessary knowledge to begin your preparation for the CCNA certification exam (640-801, or 640-821 and 640-811) and to enter the field of network administration. | Page 609 Tuesday May 20 2003 2 53 PM Password Recovery 609 Password Recovery This section explains several password-recovery techniques for Cisco routers and Catalyst switches. You can perform password recovery on most of the platforms without changing hardware jumpers but all platforms require that the router be rebooted. Password recovery can be done only from the console port physically attached to the router . Overview of Password Recovery Three ways exist for restoring access to a router when the password is lost. You can view the password change the password or erase the configuration and start over as if the box was new. Each procedure follows these basic steps Step 1 Configure the router to start up without reading the configuration memory NVRAM . This is done from what sometimes is called test system mode ROM mode or boot mode. Step 2 Reboot the system. Step 3 Access enable mode which can be done without a password if you set the configuration register correctly in Step 1 . Step 4 View or change the password or erase the configuration. Step 5 Reconfigure the router to boot up and read the NVRAM as it normally does. Step 6 Reboot the system. Some password recovery requires a terminal to issue a BREAK signal you must be familiar with how your terminal or PC terminal emulator issues this signal. In ProComm for example the keys Alt-B generate the BREAK signal by default in Windows HyperTerminal you press Break or Ctrl-Break. Windows HyperTerminal also enables you to define a function key as BREAK. From the terminal window select Function Keys and define one as Break by filling in the characters A B Shift-6 Shift-4 and uppercase B . Several free terminal-emulation packages also are available for download on the Internet which you might find preferable. The following sections contain detailed instructions for specific Cisco routers. Locate your product at the beginning of each section to determine which technique to use. Page 610 Tuesday May