Yesterday, I found 3 FastEthernet port disabled on My Catalyst Express 500 (Port 20,23 & 24):

And this is the screen shoot from the alert page:

Result of running ’#show interface status’; 3 port status =’err-dissabled’

VLAN Configuration; Port 23-24 on Default VLAN, Port 20 on VLAN 3

Taken from Forum, port with ’ERR-DISABLED’ status can be resolved by running ’shutdown’ and ’no shutdown’ on that interface:

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#config t

(config)#interface fastethernet 20

(config-if)#shutdown

(config-if)#no shutdown

In order to turn on errdisable recovery and choose the errdisable conditions, issue this command: #errdisable recovery cause ?

Another command to troubleshoot:

• show interfaces status err-disabled-Shows which local ports are involved in the errdisabled state.
• show etherchannel summary-Shows the current status of the EtherChannel.
• show errdisable recovery-Shows the time period after which the interfaces are enabled for errdisable conditions.
• show errdisable detect-Shows the reason for the errdisable status

Because ’err-disable’ on my port caused by LOOPBACK, and when I see from ’#show errdisable recovery’ command the timer status is disabled, so I need to ’enable’ and give recovery timer for loopback.

(config)#errdisable recovery cause loopback

(Config)#errdisable recovery interval 400

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Cause I am not Certified yet on Cisco, I don’t know is it a good decision or not give recovery timer for ’loopback’. I just won’t t to run ’shutdown’ & ’no shutdown’ if my port status ’err-dissable’ again. maybe u can give suggestion? I’ll apreciate it..

Update: Troubleshoot guide from Cisco:

http://www.cisco.com/warp/public/473/53.pdf

http://www.cisco.com/warp/public/473/errdisable_recovery.pdf