Tag Archive for IOS

Recovering IOS on a Catalyst Switch

Lab Prerequisites:

  • This lab will require a REAL switch as this lab cannot be emulated using GNS3.
  • The Cisco IOS on the switch must be corrupt or missing to perform this lab, to emulate this error you can erase the flash memory to practice this lab.
  • An active console session to the device is REQUIRED.
  • You’ll need to use either HyperTerminal or SecureCRT as Putty does not support xModem.

Lab Objectives:

  • Boot the switch into SWITCH ROM mode.
  • Initialize the flash file system.
  • OPTIONAL – Format the flash file system if needed. (This will remove your startup configuration)
  • Set the baud rate to 115200 to increase xmodem transfer speed and decrease time required to restore the IOS Image.
  • Copy the Cisco IOS Image via xModem to Flash:
  • Set the boot parameter to the new image name located in Flash:
  • Unset the baud so that it defaults back to 9600.
  • Boot the switch and verify that the switch boots properly.

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Recovering IOS on a 2600 Series

Lab Prerequisites:

  • You’ll need a Cisco 2600 Series router or greater that has a corrupt Cisco IOS image or NO IOS image at all. If you wish to simulate this lab you can erase the flash on your device and reboot. Please note that you’ll need to backup the Cisco IOS image prior to erasing it unless you have another image on hand that you wish to load onto the device.
  • A console connection to the device is REQUIRED
  • You’ll need a TFTP server installed on your PC to restore the image.

Lab Objectives:

  • Boot the Cisco router into ROM mode by breaking the boot sequence using the keystroke CTRL + Pause Break
  • Set the TFTPDNLD variables required to execute the procedure which include IP Address, Subnet Mask, Default Gateway, TFTP Server, TFTP Image name.
  • Execute the TFTPDNLD command and load the image into RAM using the -r switch.
  • Once booted into Cisco IOS, configure a router so that you may copy a Cisco IOS image from a TFTP server to Flash.
  • Once all necessary configuration is done copy the IOS image from the TFTP server to the flash.
  • After the copy has completed, reboot the router and verify that the image boots successfully.

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Recovering IOS on a 2500 Series

Lab Prerequisites:

  • You’ll need a Cisco 2500 Series router that has a corrupt image or NO IOS image at all. If you wish to simulate this lab you can erase the flash on your device and reboot. Please note that you’ll need to backup the Cisco IOS image prior to erasing it unless you have another image on hand that you wish to load onto the device.
  • A console connection to the device is REQUIRED.
  • You’ll need a TFTP server installed on your PC to restore the image.

Lab Objectives:

  • Boot the Cisco router into ROM mode by breaking the boot sequence using the keystroke CTRL+Pause Break
  • Change the configuration register to boot the ROM(BOOT) image. Configuration register to be used is 0x2141
  • Initialize the router by issuing the  i  command
  • Assign an IP address to the ethernet interface and configure a default gateway (if required)
  • Copy the Cisco IOS image from the TFTP server into flash memory.
  • Change the configuration register back to its default value and reload the device to ensure that the device boots up properly with the restored IOS image.

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Upgrading the Cisco IOS

Lab Prerequisites:

  • Boot R1 in the Free CCNA workbook GNS3 Lab Topology.
  • Establish an active Console Session to R1.
  • A Newer Cisco IOS Image compatible with your Cisco Device.
  • A TFTP Server is required for this lab. You may need to download Solarwinds TFTP Server and configure it prior to attempting this lab.

Lab Objectives:

  • If needed, Download and Install Solarwinds TFTP Server.
  • Place the New Cisco IOS Image file in the TFTP Server Root Directory.
  • Configure your TFTP Server and Cisco device to be within the same ip subnet, ie; 10.1.1.1/24 & 10.1.1.2/24
  • Ensure you have Ethernet connectivity from your TFTP server to the Cisco device which you’re upgrading.
  • Copy the new image file from the tftp server to your Cisco device, you will be prompted to erase the flash memory.
  • Once the new Cisco IOS Image is copied to the device flash memory, reboot the device and verify the upgrade was successful.

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