Solved

Cisco 3650 err-disabled loopback error

Posted on 2015-01-23
4
549 Views
Last Modified: 2015-01-23
Hi all

i am new at a job trying to work on a cisco issue. from showing port status i found below

FastEthernet0/6 is down, line protocol is down (err-disabled)
  Hardware is Fast Ethernet, address is 001c.f9a4.ba08 (bia 001c.f9a4.ba08)
  Description: xxx Internet access
  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Auto-duplex, Auto-speed, media type is 10/100BaseTX
  input flow-control is off, output flow-control is unsupported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 02:45:22, output 02:45:20, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     94431258 packets input, 74960012744 bytes, 0 no buffer
     Received 17641379 broadcasts (15741759 multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 15741759 multicast, 0 pause input
     0 input packets with dribble condition detected
     77517461 packets output, 28293274573 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 PAUSE output
     0 output buffer failures, 0 output buffers swapped out

I then googled err disable and found below after running in the console

Port      Name               Status       Reason               Err-disabled Vlan                         s
Fa0/6     xxx Inter err-disabled loopback

Can you please advice what i need to do to resolve the issue? I am training on cisco so not expert at it but using this experience to learn as well

Please advice

thanks in advance for your help
0
Comment
Question by:Sundeep V
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
4 Comments
 
LVL 14

Expert Comment

by:Otto_N
ID: 40565978
This error is caused when the Rx and Tx pair of a specific port get linked to each other (i.e. the port gets looped).  The default action on a Cisco switch is to put the port in err-disable state, and create a log entry.  Even after the loop is removed, the port will remain in the err-disable state until you clear the port (I find it easiest to "shut" and " no shut" the port).

I'll try to get you some additional documentation on this condition...
0
 
LVL 14

Accepted Solution

by:
Otto_N earned 500 total points
ID: 40565990
0
 

Author Comment

by:Sundeep V
ID: 40566065
Awesome, many thanks for that, will have read. I did shut down and no shutdown and this seemed to have done the trick

Is there anything i need to do to avoid this happening again ?
0
 
LVL 14

Expert Comment

by:Otto_N
ID: 40566300
Other than keeping your cables straight (I assume that is not always in your control), you can configure "errdisable recovery" (it is treated very near the end of the link provided) on the switch, which will attempt to recover err-disabled ports after a timer has expired (usually 300 seconds / 5 minutes).
0

Featured Post

Are You Headed to Black Hat USA 2017?

Getting ready for Black Hat next week? Kick things off with the WatchGuard Badge Challenge and test your puzzle and cipher skills. Do you have what it takes to earn our limited edition Firebox Badge? Get started today - https://crimsonthorn.net

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

When you try to share a printer , you may receive one of the following error messages. Error message when you use the Add Printer Wizard to share a printer: Windows could not share your printer. Operation could not be completed (Error 0x000006…
I had an issue with InstallShield not being able to use Computer Browser service on Windows Server 2012. Here is the solution I found.
There's a multitude of different network monitoring solutions out there, and you're probably wondering what makes NetCrunch so special. It's completely agentless, but does let you create an agent, if you desire. It offers powerful scalability …
Monitoring a network: why having a policy is the best policy? Michael Kulchisky, MCSE, MCSA, MCP, VTSP, VSP, CCSP outlines the enormous benefits of having a policy-based approach when monitoring medium and large networks. Software utilized in this v…
Suggested Courses

630 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question