Topic: Totally Bizzare Network Issue - Any Advice?

[gbentley]

Hi all,

I wonder if anyone can comment on the following situation?

At one of my old time clients all of a sudden, overnight, certain computers could not connect to the network (XP showing either disconnected and retrying / renewing IP icons)

I quickly figured out that when plugged into the second switch [we have 2 x 24 Port 3 Com 1GB Baseline Switches] everything worked fine.

So I plugged back in our old D-Link 100mb switch and got in touch with 3Com/HP who sent out a replacement 24 Port 1GB switch. The problem is the replacement switch exhibited the same issue. In addition it was dusty and had a cracked lid and looked for all intents and purposes like a used switch that I suspected of being sent back with the same problem. Another phone call and they have sent out what looks like a much newer switch but it too re-creates the same issue i.e. only some machines can connect but others can't. There is no problem at all with the old 100Mb switch???

I was beginning to wonder if somehow either a windows update or AV update has affected the operation of certain network card chipset drivers. To this end I took off Kasperky Workstation on one machine but this didn't make any difference. Looking at windows update didn't reveal anything in fact the last update was several days before all this happened.

Short of trying different network cards I am wondering if anyone has come across anything like this or if people have suggestions on how to go about tracking down the source of the problem?

It sure has me beat currently!

 

[purvis]

I have had switches burn out pretty fast for one reason or the other.
I have had great service,withe the Dlink switches that are bigger in nature than the consumer models. I like buying the Dlink at office depot for just over 150 dollars

[Jáder]

My tips:

1) try to isolate problem: it's on that physical port? or that machine?
2) try another OS on one of them: use a Ubuntu LiveCD/LiveDVD to do that.
3) verify the NIC autonegotiation on WinXP (turn off to test, put it at 100Full, 100Half ...)

Good luck.

Jáder

[RedBeard]

Sounds like you might have an bridging loop.  Check to see if the spanning tree protocol is enabled on the one switch but not the other. 

RedBeard