link up/down messages don't go to buffer log,why?

[riccardo_romani]

hi all in various switches 6509 series with IOS i have set "logging buffer 16384 debugging" under interface no particular command but i don't view with "sh log" if an interface goes down.

could anyone help me to understand the reason the messages don't log? thanks in advance.

bye Riccardo

[Georg Pauwen · Accepted solution]

Hello Ricardo,

by default, interface state-change messages are not sent. Try and configure the command:

logging event link-status

either globally or on your interface(s), this should get the messages in the buffer log.

HTH,

GP

[riccardo_romani]

thanks and your suggestion solved my problem , really it is not so clear how are set the default about this messages in order to view them in buffer log ; in others our switches by default the messages appears on buffers without specify the command "logging event link-status".Do you know the reasons?

bye and thanks again

Riccardo

[Georg Pauwen]

Hello Riccardo,

the default for this command is apparently IOS version related. The older versions seem to have it enabled by default, while newer ones have it disabled. I guess this is part of the evolution of IOS - in most networking environments, you do not want to see messages telling you a port goes up or down, since most ports are access ports, where users regularly connect and disconnect...

HTH,

GP

[Bobby Thekkekandam]

Hi Riccardo,

If "logging event link-status" is configured, then most likely, the logging level is configured for a severity that is not low enough to display interface changes.

you can verify this with the "show logging" command:

w250.01.06#show logging

Syslog logging: enabled (0 messages dropped, 0 messages rate-limited, 0 flushes, 0 overruns)

Console logging: level debugging, 63 messages logged

Monitor logging: level debugging, 0 messages logged

Buffer logging: level debugging, 63 messages logged

Exception Logging: size (4096 bytes)

Trap logging: level informational, 47 message lines logged

You'll want to have your logging level set to at least severity 5, or "notifications"

%LINEPROTO-5-UPDOWN: Line protocol on Interface

GigabitEthernet6/1, changed state to down

w250.01.06(config)#logging buffered ?

<0-7> Logging severity level

<4096-2147483647> Logging buffer size

alerts Immediate action needed (severity=1)

critical Critical conditions (severity=2)

debugging Debugging messages (severity=7)

emergencies System is unusable (severity=0)

errors Error conditions (severity=3)

informational Informational messages (severity=6)

notifications Normal but significant conditions (severity=5)

warnings Warning conditions (severity=4)

w250.01.06(config)#logging buffered notifications

HTH,

Bobby