Troubleshooting and Diagnostics

Below are commands to help you troubleshoot and perform basic diagnostics:

Command Description
ping {hostname | system-address} [source source-address] Reveals basic network connectivity
traceroute {hostname | system-address} [source source-address] Traces the route that packets take to reach a destination
show interfaces Displays detailed information about interface status, settings and counters
show ip route Shows the routing table of the device
show interface status Displays the interface line status
show interfaces trunk Lists information about the currently operational trunks and the VLANs supported by those trunks
show version Displays information about the IOS version, uptime and hardware configuration
show running-config Displays the current active configuration on the device
show tech-support Generates a comprehensive report of the device’s configuration and status (useful for advanced troubleshooting)
show cdp Shows whether CDP is enabled globally
show cdp neighbors [detail] Lists summary (or detailed) information about each neighbor connected to the device
cdp run
no cdp run
Enables or disables Cisco Discovery Protocol (CDP) for the device
show mac address-table Displays the MAC address table
show vtp status Lists the current VLAN Trunk Protocol (VTP) status, including the current mode