Failed loopback test error.

Unanswered Question
Aug 30th, 2007


I have a catalyst 2950. When on , ports 9 to 16 have their LED on solid orange, they are all also administratively down. When i try to do a no shut (bcos they all have a shutdown config in sho run), i get the error message below.

f0/9 can't be brought up because it failed POST in loopback test.

Any ideas.


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Jagdeep Gambhir Thu, 08/30/2007 - 05:15


Port 0/9 is not coming up and is reporting that it failed POST in loopback test. This is most likely a hardware problem.

Please get it RMA'd.



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pkaretnikov Thu, 08/30/2007 - 05:25

POST means Power On Self Test, the tests that are run at startup.

Watch the switch output during startup, It should have some sort of messages regarding those ports.

fred.mancen Thu, 08/30/2007 - 11:58

Hi buddy.

Did you try to reboot the switch again? If not, try to reboot also connected to the console and logging the messages with the Hyper Terminal. Doing this you can read the messages sent from the switch during the POST. Sometimes the switch comes up working fine. I said sometimes...I had some problems like this and the reboot worked well.

Just for the records, this kind of problem often represents a hardware problem with the ASICs.



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