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KB27771 - [CMC] How to recover root password for Chassis Management Card (CMC)

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Last Modified Date11/23/2015 8:55 PM
This article provides a video and test instructions for recovering the root password for a Chassis Management Card (CMC) on a PCS MAG 6610 or PCS MAG 6611 device.


Problem or Goal
Administrator has lost or forgotten the root password to access the Chassis Management Card (CMC) required to manage the PCS device and must perform the necessary steps to recover admin access to the device and reset the admin username/password.




To complete this task you will need the following items:

1.  Ethernet rollover cable (shipped with the CMC)
2.  PC or laptop computer with a terminal emulator (such as MSFT hyperlink).
3.  RJ45 to DB9 serial port adapter

Task List:

Part 1:  Connect laptop to CMC as management device
Part 2:  Configure terminal emulation settings on the laptop and connect to CMC
Part 3:  Execute the Junos commands that will recover the password
Part 4:  Commit the changes and reboot the CMC


Part 1: Connect laptop to the CMC

  1. Power off the CMC by pressing the power button on the front panel.
  2. Power off the laptop being used as the management device to connect to the CMC.
  3. While both devices are powered off, connect the RJ45 end of Ethernet rollover cable (supplied with the MAG Series device) into the console port on the MAG chassis and connect the serial port end to the laptop computer.

Part 2: Configure terminal emulation settings on the laptop and connect to CMC

  1. Power on the laptop computer.
  2. On the laptop computer (or other management device) launch an asynchronous terminal emulation application (such as Microsoft Windows Hyperterminal) and configure as follows:
  3. Configure a new COM port connection with the following properties and start the connection:

    Bits per second: 9600
    Data bits: 8
    Parity: None
    Stop bits: 1
    Flow control: None

  4. Once the terminal emulation connection is activated (and waiting for a response from the CMC) power on the CMC. 

Part 3: Execute the Junos Commands that will reset the password

  1. On the laptop PC, you should see boot sequence activity in the terminal window. 
  2. When the following prompt appears, press the spacebar to access the CMC's bootstrap loader command prompt::

    Hit [Enter] to boot immediately, or space bar for command prompt. 
    Booting [kernel] in 9 seconds...

  3. Enter the following command to start up the system in single-user mode:

    boot -s
  4. Watch for the following output to start the recovery process:  

    Enter full pathname of shell or 'recovery' for root password recovery or RETURN for /bin/sh: 

    And type the command recovery'.

  5. Use the following command to enter configuration mode in CLI:  edit
  6. Using the following command sequence to specify the password to be reset:
    user@host# set system root-authentication plain-text-password
  7. At the following prompt, enter the new root password. For example:
    New password: juniper1
    Retype new password:

  8. At the second prompt, reenter the new root password.
  9. After you have finished configuring the password, commit the configuration.
    root@host# commit
    commit complete

Part 4: Commit the changes and reboot the CMC

  1. Exit configuration mode in the CLI.
  2. Exit operational mode in the CLI.
  3. At the prompt, enter y to reboot the router.
    Reboot the system? [y/n] y
Related Links
Attachment 1 
Created ByData Deployment



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