I have a GSM7328Sv2 cascaded with some GS724TS (unstacked) and two tagged VLANs.

The switch works fine, but sometimes it disables itself a cascaded port (almost always the same port), without apparent reason.

When this happens :

  • The connection is interrupted
  • All other ports continue to operate normally
  • LED on the switch is off
  • Nothing obvious in logs
  • IMPORTANT: when I go Switching> Ports, I see the port with the Admin Mode column blank, while all other ports are Enable
  • When I force Admin Mode to Enable, the connection restart normally in a few seconds.

I already changed the cable.

Does anyone have an idea of the cause (a faulty switch, security reasons, storm something?) Does anyone have an idea how to prevent it happening again ?

Currently, the port shutdown almost 1x per day...

  • It might be worth checking that the switch's firmware is up-to-date.
    – Flup
    Commented Mar 13, 2013 at 13:35
  • The last time i have updated the firmware, the switch was unable to boot again.
    – Baud
    Commented Mar 15, 2013 at 11:35

1 Answer 1


In cisco land, there is a feature (port-security) which can be configured to disable a port if it sees more than some arbitrary number of MAC addresses, in order to prevent the connection of unauthorized equipment. I wonder if something like this is configurable on your device.

Failing that, it could be faulty hardware on either end, or a bug in the switch's firmware. Because updating it renders it unbootable, there is probably some faulty hardware there.

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