Tag Archive for Router

Configuring Cisco Banners

Lab Prerequisites:

  • If you are using GNS3 than load the Stub Area Networking GNS3 topology file than start R1.
  • Establish a Console session with Router 1.

Lab Objectives:

  • Configure a login banner so that any attempted connections to the device are prompted with Legal information.
  • Configure an EXEC banner so that when a user establishes an exec session with the device the device displays the hostname and current line the session was established on.
  • Configure a Message of The Day (MOTD) Banner to display current scheduled downtime for device maintenance.

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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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Initial Configuration Dialog

Lab Prerequisites:

  • If You’re using GNS3 than load the Free CCNA Workbook GNS3 topology and start R1 than establish a console session with R1.

Lab Objectives:

  • Familiarize yourself with the Initial Configuration Dialog.

Lab Instruction:

When opening a brand new Cisco box rather it be a Cisco Switch or Router, after booting the device you’ll be prompted by the Initial Configuration Dialog. You’ll also be prompted by this dialog if you do the write erase command in privileged mode and reload the device as it erases the contents of NVRAM. When a Cisco device does not have a startup-config located in NVRAM, the device will prompt you rather or not to start the Initial Configuration Dialog.

Another reason as to why you may see this is that your configuration register is set to 0x2142 which ignores the contents of NVRAM upon boot which is commonly used for password recovery.

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Cisco 2600 Series Password Reset

Lab Prerequisites:

  • A Cisco 2600 Series router or greater that has an unknown console or enable password.
  • An active Serial Console session to the device that you’re unable to log into.

 

Lab Objectives:

  • Break the boot sequence when powering on the Cisco 2600 Series router to place yourself in ROM monitor mode.
  • Change the configuration register to 0x2142 to make the router bypass the contents of NVRAM when booting then reset the router.
  • (Option 1) – Once booted, place yourself into privileged mode and copy the start up-config to the running config. Afterward, you may change the line password or enable password and write the configuration by to NVRAM by issuing the copy run start command.
  • (Option 2) – Once booted, place yourself into privileged mode and do a write erase to clear the contents of the NVRAM.
  • Now change the configuration register back to 0x2102 to boot set the router to boot normally and load the NVRAM contents upon boot.
  • Now change the configuration register back to 0x2102 to boot set the router to boot normally and load the NVRAM contents upon boot.

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Cisco 2500 Series Password Reset

Lab Prerequisites:

  • A Cisco 2500 Series router that has an unknown console or enable password.
  • An active Serial Console session to the device that you’re unable to login to.

 

Lab Objectives:

  • Break the boot sequence when powering on the Cisco 2500 Series router to place yourself in rom monitor mode.
  • Change the configuration register to 0x2142 to make the router bypass the contents of NVRAM when booting then initialize the router (boot the router into IOS).
  • (Option 1) – Once booted, place yourself into privileged mode and copy the start up-config to the running config. Afterward, you may change the line password or enable password and write the configuration by to NVRAM by issuing the copy run start command.
  • (Option 2) – Once booted, place yourself into privileged mode and do a write erase to clear the contents of the NVRAM.
  • Now change the configuration register back to 0x2102 to boot set the router to boot normally and load the NVRAM contents upon boot.

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