This is a handy command that stores log messages so they can be reviewed later. This is a default command.
It is especially useful when you are telneting between multiple routers as you would normally miss the console or debug messages on the router your not connected to.
Each logging level also enables the logging level below it, so logging console 7 or logging console debug will enable all log messages.
Router(config)#logging console <level>
|Logging severity level
Logging buffer size
Immediate action needed (severity=1)
Critical conditions (severity=2)
Debugging messages (severity=7)
System is unusable (severity=0)
Error conditions (severity=3)
Enable filtered logging
Informational messages (severity=6)
Normal but significant conditions (severity=5)
Warning conditions (severity=4)
Enable logging in XML to XML logging buffer
In this example, we will enable logging console debug.
|R2(config)#logging console debug|
Now we will telnet from R1 to R2 and check the debug output.