Console connection to router via cable

  • Cisco devices tend to not have initial IP addresses
  • we thus need to set one up (initial configuration) if we want to connect to them

  • console connection: connect to the device on a lower level than IP (e.g. to do the initial configuration)

  • connect to the console port on the router or switch via a console cable (DB9 connector - RJ45 connector)
    • gives low level direct access to the command line
  • problem: laptops don’t come with serial ports anymore (needed to connect the DB9 connector)
  • solution: USB to Serial adapter
  • newer Cisco systems use USB to Mini-USB

Putty

  • package for downloading can be found at putty.org

  • for MacOS versions, see here

  • make sure you select the correct port
    • to find the right port use your device manager (make sure the driver for your cable is installed) and check the ports (usually com3)
  • power on your router
  • bootup takes a few minutes

Use cases

  • initial configuration
  • IP address becomes unresponsive
  • troubleshoot the bootup process
    • viewing a devices’s bootup not possible via SSH since system must have booted already before the IP address goes live