Here’s a list of basic Cisco router commands commonly used for configuration and troubleshooting:

1. Accessing the Router

• enable
  Switch to privileged EXEC mode.
• configure terminal
  Enter global configuration mode.

2. Interface Configuration

• interface [type] [number]
  Enter interface configuration mode (e.g., interface gigabitEthernet 0/1).
• ip address [IP address] [subnet mask]
  Assign an IP address to the interface (e.g., ip address 192.168.1.1 255.255.255.0).
• no shutdown
  Enable the interface.
• shutdown
  Disable the interface.

3. Routing

• ip route [destination] [mask] [next-hop IP/exit interface]
  Add a static route (e.g., ip route 0.0.0.0 0.0.0.0 192.168.1.254 for default route).
• show ip route
  Display the routing table.

4. Passwords and Security

• enable secret [password]
  Set a secure privileged EXEC password.
• line vty 0 4
  Configure virtual terminal (Telnet/SSH) lines.
• password [password]
  Set a password for the terminal lines.
• login
  Enable password checking on the terminal lines.

5. Saving and Viewing Configuration

• write memory or copy running-config startup-config
  Save the current configuration.
• show running-config
  Display the running configuration.
• show startup-config
  Display the configuration saved in NVRAM.

6. Connectivity Troubleshooting

• ping [IP address]
  Send ICMP packets to test connectivity.
• traceroute [IP address]
  Trace the path to a destination.
• show ip interface brief
  Display the status of all interfaces.
• show interfaces
  Display detailed information about interfaces.

7. VLAN and DHCP

• vlan [VLAN_ID]
  Create or modify a VLAN.
• ip dhcp pool [pool-name]
  Configure a DHCP pool.

8. Backup and Restore

• copy running-config tftp
  Save the configuration to a TFTP server.
• copy tftp running-config
  Load the configuration from a TFTP server.

9. Reload and Reset

• reload
  Reboot the router.
• erase startup-config
  Clear the startup configuration.