`show logging`

The device's log buffer — the record of what changed and when.

troubleshooting

What it does

The first place to look after an unexplained outage. Interface flaps, adjacency changes, config edits and hardware faults all land here with timestamps.

Per vendor

Platform	Command
Cisco IOS	show logging
Juniper JunOS	show log messages
MikroTik RouterOS	/log print
FortiOS	execute log display

Useful variations

Interface events onlyshow logging | include LINK|LINEPROTO
Last 50 linesshow logging last 50

Pitfalls

The misreadings that actually cost people time.

The buffer is small and circular — an incident from last week is likely already gone. Ship logs to a syslog server.
Without `service timestamps log datetime msec`, entries carry uptime rather than wall-clock time and correlate with nothing.
Buffer size and severity are configurable; a quiet log may just be filtered.

show running-config show interfaces status

What it does

Per vendor

Useful variations

Pitfalls

Related