Cisco IOS Overview

CTRL + SHIFT + 6 cancels the current command.

Basics #

• enable - Enable privileged exec mode.
• configure terminal - Global configuration mode.
• hostname [hostname] - Change device name.
• banner motd # - Set the MOTD message.
• interface [interface] - Configure a given interface (e.g. editing attributes or IP address).
• copy running-config startup-config - Save configuration!
• show running-config - Show the current configuration for everything.
• show interfaces / show ip interface brief - Show interface configuration information.

Security #

• enable secret [password] - Enable a password for entering privileged exec mode.
• line [...], password [password], login - Enable password authentication for a given connection (e.g. console, over network).
  • line con 0 - Physical console port
  • line vty 0 4 - Telnet/SSH access
• service password-encryption - Enable password encryption
• Router ports are shutdown by default, switch ports are not shutdown by default.

Routing #

Manual routing is prone to error and becomes admin overhead, use Routing Protocols where possible.

• ip route [dest network] [dest netmask] [next router] - Create a static route to another network.