[Wolves] Funny happenings with LTSP

[Mark Ellse]

Adam,

Many thanks for these suggestions.

Can you manually examine the config on the switch? It's possible there
> is some residual config left somewhere, perhaps the use of VLANs which
> restrict access to certain switch ports.
>

I can. And I have done. There doesn't seem to be anything causing a problem.
And since I've tried two switches, it would be highly coincidental with them
both stopping the same thing. And if I connect to the same port of the
managed switch that doesn't work with a client, via a normal dumb switch,
LTSP works fine.


>
> Other than that, Gb ethernet uses all 4 pairs on an ethernet cable,
> unlike 10 and 100 MB, which only use 2 pairs. As a result, as Alex
> suggested, 100 Mb will often work on cables with broken pairs, where Gb
> ethernet exposes the fault and won't work.
>

I take this point. But the ports that I am trying to use are the 100M ports.


The only other thing I can think is maybe your clients are failing to
> auto-negotiate the speed setting when 1GB is available.


When my daughter suggested this, I thought it the most likely issue. It does
seem to be almost something at a hardware level since putting a dumb switch
between the non-working client and the managed switch makes the client work.
So, obviously, everything necessary is getting through the managed switch.

I also thought that it couldn't be a problem with spanning tree, which I did
try disabling, but it made no difference. If spanning tree had been a
problem, it would have been so even with the dumb switch in place.

The managed switch ports were initially set to auto and I moved them to 100M
to check the issue of negotiation. No improvement.



> This seems
> unlikely to be honest but you could check it by booting your thin
> clients from a live CD or USB stick and using ethtool when attached to
> the Gb switch, e.g.:
>
ethtool eth0
>
> It's possible that you might need to install ethtool inside the live CD
> environment depending on what you use, which is do-able but not when
> your switch doesn't work ;)
>
> This is a good idea. There are one or two ideas to try first, but I'll put
this on the list.

I am going to try a different network card and see if it is a problem with
the onboard NIC.

After that I am scratching around. (LTSP does not like blue? The managed
switch is blue. Try painting the managed switch the same colour as the dumb
switch?.........)

The bottle of champagne is still going.

Mark
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