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SG500-28P Power Loss & Amnesia



I had a very strange occurrence recently which I suspect has corrupted my Cisco SG500-28P switch.

A couple days ago the power went out and the switch turned off, shortly after the power returned... but the switch did not power back on.


I pulled the power cable out and plugged it back in, all the port lights lit up, then went out. I believed the switch to be dead, but the fans were still going and all connected devices were hinting of a connection of some kind, but it certainly was not normal.


I connected a serial cable and took a closer look. Rebooting the switch I watched the boot sequence then noticed the switch MAC address was FF:FF:FF:FF:FF:FF. The boot sequenced seemed to end with the switch prompting for me to enter a new MAC address as the current was invalid. Assuming it was after the original MAC, I entered the one listed on the sticker on the back. It then went on to ask me the hardware revision number. Puzzled, I rebooted it again without entering this information (so the MAC was all I entered). This time it started up normally, all lights were on and things started taking.

It seemed everything was OK, then I noticed the switch configuration had changed a bit. L3 was no longer enabled and IP interfaces had changed. DHCP had been re-enabled and other little things like that had changed. While this is all  fixable, I did notice a couple things which were concerning, namely the missing serial number on the System Summary page.


I think the power outage seriously screwed up the switch. I reset it to factory defaults hoping that would fix it but alas it did not.


The switch appears to be working now, but it is still missing its serial number. I don't know what else may be missing, but I no longer trust the switch to perform its function. I don't want to be using a switch with amnesia.


Can anyone recommend any way to fix this sort of problem, or should I contact Cisco Support for a replacement device?


Hello,It almost sounds like


It almost sounds like you got into the setup menu from the factory somehow.  I have never seen those menus myself, but I would say there is definitely something odd going on with your switch.

Since your serial number and MAC address have been lost it sounds like an issue with the switch's flash memory possibly.  Go ahead and give us a call at the SBSC and we can get a case open to possibly replace that device for you.

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