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Certain computers not getting connection to certain switches after power surge

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  • 1.  Certain computers not getting connection to certain switches after power surge

    Posted Sep 04, 2014 12:28 PM

    Gentlemen,

    I've run into a weird issue I hope some of you can help me with.  I have two specialized windows based machines that will now not connect to a switch. This happened after we had a power surge in one of our buildings. The machines connect to an Aruba S2500. After the surge, the switch was hung and was rebooted. After the reboot the machines would no longer connect, even at the physical layer. The odd thing is this: I have replaced the switch entirely, and they still cannot connect. Other hosts can connect to those exact same lines, and get correct addresses with no problems. This rules out any kind of a routing issue, cabling issue, etc. The only thing I can think of is that changes were made to that switch's config and weren't saved to memory, and when it rebooted, the saved config differed somehow. What is even more odd is that other machines of the exact same model will work on those same connections and the ones we took that weren't working, WILL work at a different site. There's nothing I can see in the switch config that would be blocking and mac addresses(and it doens't make sense that those two machines would've ever been blocked) and also the machine doesn't even try to connect, it doesn't even see the physical circuit being completed.  

     

    Any Ideas?



  • 2.  RE: Certain computers not getting connection to certain switches after power surge

    EMPLOYEE
    Posted Sep 04, 2014 07:07 PM

    Newton,

    Let me confirm a few things here:

     

    • 2 Specialized Clients (Let's call them Alpha and they are from the surge site)
    • 2 Specialized Clients (Let's call them Beta and they are from the non-surge site)
    • S2500 at Location A (which experienced the power surge)
    • S2500 at Location B (did not experience a surge)

    When Alpha Clients Connect to Location A they don't work

    When Alpha Clients Connect to Location B they work

    When Beta Clients Connect to Location A they work

    When Beta Clients Connect to Location B they work

     

    When the Beta Clients are connected at Location A, they are using the same patch cords, patch panels, therefore the exact same path?

     

    Can you put a mini-switch/hub in line between the Alpha clients closer to their side and the S2500 and see if they come up? If they do, can you tell if they are using 10/HALF or 100/FULL from a negotiation perspective. We could tweak these around natively on the S2500 but I was curious to see if there is anyway to get them up at Location A first.

     

    Also, have you tried putting the clients closer to the switch, e.g. 6 foot patch cord?

     

    Best regards,

     

    Madani



  • 3.  RE: Certain computers not getting connection to certain switches after power surge

    Posted Sep 05, 2014 02:11 PM

    You are correct with Alpha, Beta client statements.

     

    I haven't tried putting an unmanaged switch/hub between the Alpha clients and the s2500, but that is definitely worth a shot.

     

    An interesting development though is this: I've taken one of the Alpha clients and connected to a completely different site, that is still wtihin our network. It is on a completely different s2500 and subnet. We'll call this location C. 

     

    So, the Alpha clients CANNOT connect at Location A

     

    Beta Clients CAN connect at Location A

     

    The Alpha Clients CAN connect at Location B(which is where our main data center is located, but obviously we have it segregated into several different vlans.)

     

    The Alpha Clients CANNOT connect at location C

    The Beta Clients CAN connect at location C.

     

    Also, yes we've tried connect the Alpha Clients to Location A with a smaller patch cable, circumventing the long cable run.

     

    Thanks