4 - Cisco IOS

Question 1

Connecting to Cisco device via network

Answer 1

• SSH in via PuTTY

Question 2

Connecting to Cisco device via console port

Answer 2

• Cisco devices don’t receive an IP address by default, meaning we need to physcially connect and assign one
• Console cable = yost/rollover cable = DB9 to RJ45
• New console cable = USB to mini USB
• Used to complete initial config too

Question 3

Navigating the IOS CLI

Answer 3

• Router> = user exec level
• en = brings the CLI up to privileged exec, Router> changes to Router#
• disable / disa = brings us down a level to user exec
• di ? = shows us the avilable commands

Question 4

Navigating the IOS CLI #2

Answer 4

• sh = show command that shows info about device
• debug = debugs
• show and debug can only be used at the privileged exec mode, if we aren’t on this level, put ‘do’ at the front

Question 5

Navigating the IOS CLI #3

Answer 5

• cntrl a = moves to the start of the line

- end = drops level to user exec

Question 6

IOS Configuration

Answer 6

• we have 2 configs on the device, running config and startup config which is used whenever the device is booted up
• config t = enters global config
• show start = shows startup config
• show run = shows running config
• if we mess up the current config, we can reboot to run the startup config as a last resort

Question 7

IOS Configuration #2

Answer 7

• copy run flash:filename = saves running config to flash memory on the device
• not a good idea to back up a device on the same device
• copy run tftp
  enter IP address
  enter filename
• This saves the running config on the tftp server

Question 8

IOS Configuration #3 - Where is the OS+configs stored?

Answer 8

• the OS is stored on the flash memory in the device
• startup config is stored in NVRAM
  (non volatile, meaning the data persists through reboots)
• running config is stored in RAM, after being transferred from NVRAM after boot