[geeks] Whee! Lightning strikes, AGAIN!

[Barry Keeney]

On Wed, 29 Jul 2009, Lionel Peterson wrote:

> On Jul 29, 2009, at 12:20 PM, Barry Keeney <barryk at chaoscon.com> wrote:
> 
> > On Wed, 29 Jul 2009, Lionel Peterson wrote:
> >> The dead switches, router, and cable modem all power on, but have  
> >> dead
> >> NIC ports, again, discounting the idea a power surge came in the  
> >> power
> >> line in my mind.
> >
> >  Well it's still possible that the surge entered from the power grid
> > and moved to the network devices via a poorly designed device(s)  
> > (switch,
> > router, etc) that allowed the surge passed it's power supply to the
> > network cables.
> 
> Wouldn't a lethal surge take out the system that took the hit? 

  Depends, sounds like the NIC's jump in front of the bullit giving thier
up lives and not passing the charge into the rest of the computer. 

> All I  
> lost were NIC ports, the WAN and ETH1 ports on my router, the LAN port  
> on the cable modem, and *only* the switch ports that had wires died...

  I can't say for sure that any of this is going to be your problem, 
but could give you some ideas on what else to check...

  It sounds like, from what I remember, you have a larger switch,
something around 24 ports? They normally have several chips controlling
the ports, smaller 4-8 port switchs can have as little as one ethernet
chip. More chips, the more that have to be damaged to cause all the 
dead ports.

  I would guess that the surge didn't come from the switch and only 
passed thru it using a common path shared by the used ports. Without
looking inside I would think it was a ground path(s). All the signal
leads would pass strait into the chip and it would be harder for the 
surge to keep moving to ports on other chips. 

  It could be something between the jack and the controller chip(s) 
inside the switch (cap, diode, etc) then it's likely the surge came 
in from the network and passed to other used ports using something
shared, like a ground. No cable in a port means that the network cable 
was some how required and without it the surge didn't have a path to
whatever device that died on the cabled ports or into the chip or part 
of the chip controlling that port. Possible damage to the ethernet chips, 
but still working.

  If the surge cable from just the power supply on the switch it would
likely fry something that would have killed the whole switch or fried
all the ports controlled by whatever chip(s) have cabled ports attached.
The surge passed thru controller chip(s) to the network cables, should
have kill the whole chip.

  If all the systems still work, just bad NIC's, the surge didn't come
from any of them. Whatever killed the NIC's would likely kill something on
the system as well, memory, CPU, disk controllers, CD/DVD/hard drives,
something before passing into the network.

  If the router still has working network ports (like the switch), it's 
most likely the cable modem that passed the surge in. If you plan on
using ethernet cable surge protection and want to keep it cheap, I'd put
one between the cable modem and the router. If you're not sure if it's 
the modem or router, use two. One between the modem and the router, and
one between the router and the switch.

  Also a good idea to double check the electrical outlets, they could have
grounding problems as well. It's also possible that there is something
in the house wiring done wrong or badly. If you can have someone take a
general look it couldn't hurt. I've got a friend who's an electrican so
something like this cost a 6-pack.

  I also check the ethernet cables (kind of hard if they're in walls) for
damage. Small cridders sometimes like to chew on them or they were
damaged as they were pull thru and there might be a short(s)

  Nope this helps... 

Barry Keeney
Chaos Consulting
email barryk at chaoscon.com

"Rap is Square Dancing gone terribly, terribly Wrong...." 

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