Essential commands to verify and troubleshoot Cisco device configurations and operational status.

Step 1: Basic system information Display device model, IOS version, uptime, and memory usage.

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Router>enable
Router#show version
Router#show inventory
Router#show processes cpu
Router#show memory

Interface status and configuration

Check interface operational status, configuration, and statistics.

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Router#show interfaces
Router#show interfaces brief
Router#show ip interface brief
Router#show interfaces gigabitEthernet 0/0
Router#show interfaces description

Routing information** View routing table, protocols, and neighbor relationships.

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Router#show ip route
Router#show ip route summary
Router#show ip protocols
Router#show ip ospf neighbor
Router#show ip eigrp neighbors

Step 4: VLAN and switching (for switches) Display VLAN database, port assignments, and MAC address table.

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Switch#show vlan brief
Switch#show interfaces trunk
Switch#show mac address-table
Switch#show spanning-tree
Switch#show port-security

Step 5: Running and startup configurations Compare current configuration with saved configuration.

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Router#show running-config
Router#show startup-config
Router#show running-config interface gigabitEthernet 0/0
Router#show running-config | include ip route

Step 6: Logs and troubleshooting Check system logs, CDP neighbors, and ARP table.

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Router#show logging
Router#show cdp neighbors
Router#show cdp neighbors detail
Router#show arp
Router#show ip arp

Key Points:

• Use show running-config | include keyword to filter specific configurations
• show ip interface brief is the fastest way to see all interface status
• Add | begin, | section, or | exclude to filter command output
• Use show ? to see all available show commands for your device