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Cisco Basic Commands

A practical beginner guide to the most important Cisco IOS commands for navigation, verification, interface checks, routing checks, and basic troubleshooting.

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Cisco Basics CLI Study Guide

Cisco Basic Commands Guide

This guide introduces essential Cisco IOS commands for moving around the CLI, checking interface status, reviewing configuration, testing connectivity, and saving changes correctly.

Why These Commands Matter

  • They help you navigate the device with confidence.
  • They help you quickly see whether ports and IP addresses look correct.
  • They help you inspect configuration without guessing.
  • They form the base for most troubleshooting tasks.

Basic Navigation Commands


enable
configure terminal
exit
end
disable
  • enable enters privileged EXEC mode.
  • configure terminal enters global configuration mode.
  • exit leaves the current mode.
  • end returns directly to privileged EXEC mode.
  • disable returns to user EXEC mode.

View Configuration


show running-config
show startup-config
show running-config interface GigabitEthernet0/1
  • show running-config shows the active configuration.
  • show startup-config shows the saved configuration used after reboot.
  • show running-config interface GigabitEthernet0/1 shows config for one interface only.

Save Configuration


copy running-config startup-config
write memory

Always save after making changes. If you do not, the device may lose the changes after reboot.

Check Interfaces


show ip interface brief
show interfaces
show interfaces status
  • show ip interface brief gives a quick summary of interface state and IP address.
  • show interfaces gives detailed counters, errors, duplex, and speed information.
  • show interfaces status is useful on switches for port state and VLAN info.

How to Read Interface Status

  • up / up means the interface is working.
  • administratively down usually means the port is shut down.
  • down / down usually means no physical link or cabling issue.

Check Connectivity


ping 8.8.8.8
traceroute 8.8.8.8
show arp
show mac address-table
  • ping checks reachability.
  • traceroute shows where traffic is going and where it may stop.
  • show arp shows IP-to-MAC mappings.
  • show mac address-table shows where MAC addresses are learned on a switch.

Check VLANs and Switching


show vlan brief
show interfaces trunk
show spanning-tree
show mac address-table dynamic
  • show vlan brief lists VLANs and assigned access ports.
  • show interfaces trunk shows trunk ports and allowed VLANs.
  • show spanning-tree helps verify whether a port is forwarding or blocked.
  • show mac address-table dynamic shows dynamically learned MAC entries.

Check Routing


show ip route
show ip protocols
show running-config | section router
  • show ip route displays the routing table.
  • show ip protocols shows routing protocol information.
  • show running-config | section router filters the routing part of config.

Basic Interface Configuration Example


configure terminal
interface GigabitEthernet0/1
ip address 192.168.10.1 255.255.255.0
no shutdown
end
copy running-config startup-config

Simple Troubleshooting Flow

  1. Check interface state with show ip interface brief.
  2. Confirm the configuration with show running-config.
  3. Test connectivity with ping.
  4. Use traceroute if traffic is not reaching the destination.
  5. Save changes after the issue is fixed.

Common Mistakes

  • Forgetting to use enable before privileged commands.
  • Making changes but not saving them.
  • Checking the wrong interface.
  • Ignoring interface status before deeper troubleshooting.