2012年1月15日

Password Recovery Procedure 2600

1.Press Break(CTRL+Break) on the terminal keyboard within 60 seconds of power up in order to put the router into ROMmon.


2.hostname confreg 0x2142This step bypasses the startup configuration where the passwords are stored.


3.hostname > reset
The router reboots, but ignores the saved configuration.


4.Type no after each setup question, or press Ctrl-C in order to skip the initial setup procedure.


5.hostname > enable 


6.hostname# configure memory or copy startup-config running-config 
in order to copy the NVRAM into memory.


Warning: Do not type copy running-config startup-config or write. These commands erase your startup configuration.


7.Type show running-config.
The show running-config command shows the configuration of the router. In this configuration, the shutdown command appears under all interfaces, which indicates all interfaces are currently shut down. In addition, the passwords (enable password, enable secret, vty, console passwords) are in either an encrypted or unencrypted format. You can reuse unencrypted passwords. You must change encrypted passwords to a new password.

8.hostname(config)# configure terminal

9.hostname(config)# enable secret 00000


10.Issue the no shutdown command on every interface that you use.


11.hostname(config)# config-register 0x2102


12.hostname# write memory or copy running-config startup-config




Configuration Register Values
The factory-default setting for the configuration register is 0x2102. This indicates that the router should attempt to load a Cisco software image from Flash memory and load the startup configuration with a console speed of 9600 baud.
Configuration Register Setting
Router Behavior
0x102
    • Ignores break
    • 9600 console baud
0x1202
    • 1200 baud rate
0x2101
    • Boots into bootstrap
    • Ignores break
    • Boots into ROM if initial boot fails
    • 9600 console baud rate
0x2102
    • Ignores break
    • Boots into ROM if initial boot fails
    • 9600 console baud rate default value for most platforms
0x2120
    • Boots into ROMmon
    • 19200 console speed
0x2122
    • Ignores break
    • Boots into ROM if initial boot fails
    • 19200 console baud rate
0x2124
    • NetBoot
    • Ignores break
    • Boots into ROM if initial boot fails
    • 19200 console speed
0x2142
    • Ignores break
    • Boots into ROM if initial boot fails
    • 9600 console baud rate
    • Ignores the contents of Non-Volatile RAM (NVRAM) (ignores configuration)
0x2902
    • Ignores break
    • Boots into ROM if initial boot fails
    • 4800 console baud rate
0x2922
    • Ignores break
    • Boots into ROM if initial boot fails
    • 38400 console baud rate
0x3122
    • Ignores break
    • Boots into ROM if initial boot fails
    • 57600 console baud rate
0x3902
    • Ignores break
    • Boots into ROM if initial boot fails
    • 2400 console baud rate
0x3922
    • Ignores break
    • Boots into ROM if initial boot fails
    • 115200 console baud rate


If the value not in the table, determine which bits are set in order to compute the value:
Bit Number
Hex
Meaning
00-03
0x0000-0x000F
Boots Field Parameters:
  • 0x0000 - Stays at the system bootstrap prompt.
  • 0x0001 - Boots the first system image in onboard Flash memory (EPROM).
  • 0x0002-0x000F- Specifies a default netboot filename. Enables boot system commands that override the default netboot filename.
06
0x0040
    • Ignore NVRAM contents
07
0x0080
    • Disable boot messages
08
0x0100
    • Break disabled
10
0x0400
    • IP broadcast with all zeros
5,11,12
0x0020, 0x0800, 0x1000
    • Console line speed
13
0x2000
    • Boots default ROM software if network boot fails
14
0x4000
    • IP broadcasts do not have net numbers
15
0x8000
    • Enables diagnostic messages
    • Ignores NVRAM contents