From: Daniel Bauer <linux@daniel-bauer.com> Date: Mon, 10 Jul 2023 10:45:30 +0200 Am 10.07.23 um 08:33 schrieb Bob Rogers:
The only think I can think of that would cause this behavior is that somehow the switch is being fooled into thinking that the Ethernet address for that port has changed when in fact it hasn't. (That should only explain failure to receive packets, but depending on the nature of the failure, it might screw up sending as well.)
What could make the switch being fooled - after 7 days working uptime? I have no theory there. I've been playing with networks for almost forty hears, but I have to say you have an unusually weird situation on your hands. Even in the early of dumb 10baseT switches, it was easy to persuade them to update their routing information by pinging in the other direction, a solution which obviously isn't working for you.
Plugging in another system forces the switch to reconsider, which fixes the problem.
Ok, that explains to me why plugging it into the laptop makes a change. Yes, that was a big clue in that particular direction.
And if attempting to make connections from your PC fails, then it's not surprising that unplugging/replugging doesn't help either. This also goes a long way to proving that it's not your PC's fault.
Have you tried permuting the connections to the switch? (And sorry if this has already been suggested.)
Sorry for my lack of English... With "permuting the connections to the switch" you mean plugging the cable into another port/plug of the switch? Yes. Actually I haven't tried this. It would be interesting to know if the problem stays with the port, or follows your PC. Or, if it requires the combination of port and PC, then moving the cable will "cure" it. In any case, you might then decide it would be worth replacing the switch.
... How long did you leave it unplugged? Small switches don't need much power, so if they have an even halfway decent power supply, they can remember routing information for a surprisingly long time, perhaps a few minutes even. Or there may even be an NVRAM cache for routing info.
Only some seconds, maybe half a minute... -- Daniel Bauer photographer Basel Málaga So perhaps long enough, perhaps not. Looking at the datasheet for the Netgear GS308PP [1], it doesn't look like it has an NVRAM cache for its MAC address table. So maybe next time this happens, you could try unplugging the switch for a probably-excessive 5 minutes while keeping the PC plugged in, and seeing if the PC can still connnect after repowering the switch. And unplug the adapter from the wall while keeping the switch connected to the adapter, so the switch can drain the capacitor(s) in the adaptor power supply. The datasheet also says that the Netgear GS308PP has 4K MAC address table entries, so we can rule out table overflow as a reason for "forgetting" your PC. ;-} -- Bob Rogers http://www.rgrjr.com/ [1] https://www.netgear.com/images/datasheet/switches/300-Series_Unmanaged_PoE_D...