Cisco show log

[blin]

What can show log do?

1. It shows port state, for example "Line protocol on Interface GigabitEthe rnet0/15, changed state to down" and "Line protocol on Interface GigabitEthe rnet0/15, changed state to up"
2. It shows errors and causes, for example, "Gi0/21 is not compatible with Gi0/23
and will be suspended (flow control receive of Gi0/21 is on, Gi0/23 is off)", "Received BPDU on port Gi0/21 w
ith BPDU Guard enabled. Disabling port", and "bpduguard error detected on Gi0/21, putt
ing Gi0/21 in err-disable state"


show log
Syslog logging: enabled (0 messages dropped, 0 messages rate-limited, 0 flushes,
0 overruns, xml disabled, filtering disabled)

No Active Message Discriminator.

No Inactive Message Discriminator.

Console logging: level debugging, 633 messages logged, xml disabled,
filtering disabled
Monitor logging: level debugging, 0 messages logged, xml disabled,
filtering disabled
Buffer logging: level debugging, 633 messages logged, xml disabled,
filtering disabled
Exception Logging: size (4096 bytes)
Count and timestamp logging messages: disabled
File logging: disabled
Persistent logging: disabled
Trap logging: level informational, 635 message lines logged

Log Buffer (4096 bytes):
tate to up
Jul 23 20:09:15.408: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthe
rnet0/15, changed state to down
Jul 23 20:09:18.453: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthe
rnet0/15, changed state to up
Jul 24 20:28:05.845: %EC-5-CANNOT_BUNDLE2: Gi0/21 is not compatible with Gi0/23
and will be suspended (flow control receive of Gi0/21 is on, Gi0/23 is off)
Jul 24 20:28:07.380: %SPANTREE-2-BLOCK_BPDUGUARD: Received BPDU on port Gi0/21 w
ith BPDU Guard enabled. Disabling port.
Jul 24 20:28:07.380: %PM-4-ERR_DISABLE: bpduguard error detected on Gi0/21, putt
ing Gi0/21 in err-disable state