What each command does, how it differs per vendor, and the mistakes that cost time. Searchable offline.
show ip routeroutingDisplays the IPv4 routing table — what the device will actually do with a packet.
6 vendor variants · 3 pitfalls
show ip interface briefinterfacesOne line per interface: address, and both status columns.
6 vendor variants · 3 pitfalls
show interfaces statusinterfacesSwitchport view: VLAN, duplex, speed and link state per port.
3 vendor variants · 2 pitfalls
show vlan briefswitchingVLANs known to the switch and which access ports are in them.
5 vendor variants · 3 pitfalls
show ip ospf neighborroutingOSPF adjacency state per neighbour — the first stop when routes are missing.
4 vendor variants · 4 pitfalls
show ip bgp summaryroutingBGP peer states and prefix counts per neighbour.
4 vendor variants · 4 pitfalls
show spanning-treeswitchingSTP topology: root bridge, port roles and which ports are blocking.
4 vendor variants · 3 pitfalls
show mac address-tableswitchingWhich MAC addresses the switch has learned on which ports.
5 vendor variants · 3 pitfalls
show arptroubleshootingIP-to-MAC bindings the device has resolved.
5 vendor variants · 3 pitfalls
show running-configverificationThe configuration currently in effect, in memory.
5 vendor variants · 3 pitfalls
show loggingtroubleshootingThe device's log buffer — the record of what changed and when.
4 vendor variants · 3 pitfalls
show access-listssecurityACL contents with per-rule hit counters.
4 vendor variants · 3 pitfalls