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I've the most strange behavior from one of the computers on my work network...

The network is composed by a Cisco switch and about 10 computers... ( my position in the company is senior programmer, and so I don't have all the information about the network )..

The computer with this behavior is a Windows XP SP3, P4 2Ghz and 1GB of ram.. formatted last week, I only installed on this computer two things, Wamp stack ( Wampserver ), and no-ip DUC client.. at least so far, I also want to install Mercurial, but I'm not going to bother until I solve this problem..

The problem is the following, I start pinging the server with ping ip -t, and my computer starts pinging that computer with no problem, but after a while it starts giving..

Reply from bytes=32 time=68ms TTL=128
Reply from bytes=32 time=68ms TTL=128
Reply from bytes=32 time=68ms TTL=128
Reply from bytes=32 time=68ms TTL=128
Destination host unreachable.
Destination host unreachable.
Destination host unreachable.
Reply from bytes=32 time=68ms TTL=128
Reply from bytes=32 time=68ms TTL=128
Reply from bytes=32 time=68ms TTL=128

It keep's on pinging the machine and then it starts failing again, and it keeps on doing this all day long.. if I'm using Windows RDP while pinging, the RDP simply closes, with no warning what so ever..

Looking at task manager of that computer, what I get is a cyclic wave with peaks of 100% of CPU use, that matches exactly with the time that the ping fails...

We already tried two thing's, change the port where the cable was connected, and connect the computer directly to the switch, and that produced no result..

I'm using this server as a pre-deployment server for our sites, I'm developing on my local machine using the database on the server, that means that I'm constantly requesting access to the database on that computer..

But I don't think that this constant requests are the cause for this behavior... I think.. I'm not sure..

I've already checked the windows event log, and nothing was showed regarding this problem..

This also happens when I'm not pinging the computer, after I installed Wampserver, I started to use the database almost immediately.. and when doing some refreshes, the database connection on the PHP page simply timed out.. that's when I figured something was wrong with that computer or with the network...

But for example, this morning I was able to work with no problem whatsoever, only in the afternoon it started again with this strange behavior..

Edit: I forgot to mention something, after disabling a lot of services, the interval in which the ping fail's increased that means that the I could ping the machine more, and the ping failing decreased..

Thanks in advance for any insight on this problem..

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What's using the CPU? Is it a user process or system thread? It could be your network card driver going flooey every so often. – MikeyB Feb 7 '11 at 17:28
I couldn't find the process that is using the processor... Every time I reach the machine the spike as already passed.. I' ve disabled a lot of services on the machine.. Even the printing service... Thanks.. – Tio Feb 8 '11 at 9:23
up vote 0 down vote accepted

On old hardware like this, I would suspect hardware trouble: try replacing the network card.

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One of network admins is bringing a nic tomorrow, to see if it works.. Let's hope so.. Thanks.. – Tio Feb 8 '11 at 19:56
after a few days the network admin, bought a new NIC, and everything is working perfectly now.. thanks.. – Tio Feb 21 '11 at 18:17
Excellent, thanks for reporting back :-) – DutchUncle Feb 21 '11 at 18:22

This could be indicative of a MAC address conflict also, which a NIC replacement would resolve.

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