Am 10.07.23 um 08:33 schrieb Bob Rogers:
>     From: Daniel Bauer <linux@daniel-bauer.com>
>     Date: Sun, 9 Jul 2023 13:00:39 +0200
> 
>     Just the same as described in my first post happened again tonight:
> 
>     Suddenly (like after approx. 100 of running normal) the connections on
>     eth0 tpo the IP's behind the switch get lost. I can ping the switch, but
>     not the other IP's connected to that switch.
> 
> ...
> 
>     BUT: plugging the the switch to my laptop all IP's are available on the
>     laptop immediately, then plugging back the cable to the PC they appear
>     there as well...
> 
> ...
> 
> 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?

> 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.

> 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?

Actually I haven't tried this.
> ...
> 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...


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