In this article, I will give an example of configuring and viewing debug information on Cisco switches. For an example and a test, I will take a Cisco Catalyst 6509-E switch.
First, turn off displaying logs in the console and sending them to a remote server:
no logging console
no logging monitor
no logging 192.168.2.2
Let’s clear the old logs so that they don’t interfere:
clear logging
We indicate the display of time in the logs with milliseconds:
service timestamps log datetime msec
service timestamps debug datetime msec
service timestamps debug datetime msec localtime show-timezone
Any of the commands below will enable the display of the necessary debug information:
debug ?
debug ip packet detail
debug ipv6 packet detail
debug arp
...
Let’s see the logs:
show logging
show log
After the necessary time, be sure to disable the recording of debug information to the logs:
undebug all
You can also change the size and level of logging from 0 to 7, where 0 is the minimum information:
logging on
logging buffered 0-7
logging buffered 4096-2147483647
0 – emergency: System unusable
1 – alert: Immediate action needed
2 – critical: Critical condition
3 – error: Error condition
4 – warning: Warning condition
5 – notification: Normal but significant condition
6 – informational: Informational messages
7 – debugging: Debugging messages
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