Intro to the CLI | Day-4

• Cisco IOS is the operating system used on Cisco devices
• CLI stands for command-line interface, used to configure Cisco devices like routers, switches, and firewalls
• Connecting to a Cisco device via the console port involves bringing your laptop to the device and connecting to the console port
• To connect to a Cisco device, you need a rollover cable with an RJ45 connector on one end and a DB9 connector on the other end
• To access the CLI, you need to use a terminal emulator like PuTTy with specific settings: speed of 9600 bits per second, 8 data bits, 1 stop bit, no parity, and no flow control
• User EXEC mode is indicated by the 'greater than sign' next to the hostname of the device, while privileged EXEC mode is indicated by a pound sign
• In privileged EXEC mode, you have complete access to view the device's configuration and can make changes like setting a password to protect privileged exec mode
• The configuration files on a Cisco device include the running-config (current active configuration) and the startup-config (loaded upon device restart)
• Use the 'show running-config' command in global configuration mode to view the running configuration file
• To view the running configuration file, use the 'show running-config' command in global configuration mode
• The 'enable password CCNA' command is in the running-config
• To view the startup configuration file, use the 'show startup-config' command
• If the startup-config is not present, it means the running configuration has not been saved
• To save the running-configuration as the startup-configuration, use one of these commands in privileged exec mode:

  • 'write'
  • 'write memory'
  • 'copy running-config startup-config'
• Using 'service password-encryption' in global configuration mode encrypts all passwords in the configuration file
• The 'enable password' command sets a plain-text password for privileged exec mode
• The 'enable secret' command configures a more secure password for privileged exec mode, always encrypted with MD5 encryption
• To cancel or delete a command, use 'no' in front of the command
• If 'service password-encryption' is enabled:

  • Current passwords will be encrypted
  • Future passwords will also be encrypted
• If 'service password-encryption' is disabled:

  • Current passwords will remain encrypted
  • Future passwords will not be encrypted
• In the Cisco CLI, 'enable' enters privileged exec mode, 'configure terminal' enters global configuration mode, and 'show running-config' displays the current configuration
• To save the running configuration as the startup configuration, use 'write', 'write memory', or 'copy running-config startup-config'