So here's the deal:
I have a new PC to go into an office.
I patch the datapoint in new office into switch.
I plug in new PC and all I get from lights on network card is flashing green light regularly about every 2 seconds...no solid light and no connection in Windows.
I plug laptop into same datapoint and it gets connection fine.
I test PC on different datapoint and works fine.
I plug PC back into datapoint in original datapoint it doesn't work again.

I have tried swapping the following:
-different datapoint in office (there is three, one for phone, which works - for the phone). None of the three datapoints in the office work with the PC but they all work with phone or laptop.
-different patch leads both at switch and between datapoint and PC.
-different switch port

The only thing I can possibly come up with is maybe the cable run to the office is too long and it works fine with the laptop because it has a different brand of network card that can handle slightly weaker signal than PC.

Sorry if my post seems to be one big ramble but this is bugging the s*** out of me as I need the PC running tomorrow...has anyone got any brilliant ideas?

check terminations on outlet, does the computer work if you plug straight into the switch ? with a small path lead ?

length of data cable no greater than 70 metres ?

chuck some dirty old intel PCI nic into it - should come up trumps

I've had this exact problem, in the end I did a format and Windows was all good again, prolly a bit far but I was over it.

any mac accounting on that switch port ?

rolo, your comments are just showing your ignorance
i have experienced this before. some of the chipsets for onboard nics aren't as strong as the old Intel PCI nic - and they provide exactly the same function. Chances are coochie doesn't have gigabit to the desk, so an old 10/100'der will do fine.
You could always try stepping it down to 10meg or half duplex (or both!) to see if you have a win.

acetame's on the money, try connecting with a short patch lead directly into the switch.

Also make sure the the patch cables you're running are straight through and not cross-over ( some switches and network cards have auto-detect of these which could make one work and not the other ). Easiest way to tell is a crossover has the green and orange wires crossed over, so check the heads of both ends, if they're the same you're good.

If you have a cross-over, try connecting the PC directly to the laptop and give them both static IPs and see if they can see eachother.

finally if you do have a spare nic, chuck it in and see if it works, you could have a faulty NIC onboard. If that's the case though ultimately you'd want to get it replaced rather than a retarded bandaid solution like using an old intel nic.

Easy way to test for a not-so-perfect cable would be to change the new pc down to 10mb half duplex, if it gets a connection and can browse network etc you can pretty much say its a dodgy cable.

I've seen this happen heaps of times before, a machine has been hooked up to a data point for ages working fine, new pc comes in and doesnt work. Could have been that the old one was 10mb and new one is 100mb or the old one was 100mb and the new is 1gig, or even that the newer card is lesser quality than the old one.

I love how rolo_tomasi craps on but doesnt give any solution.

last edited by `ViPER` at 18:38:51 19/Aug/08

it sounds like he needs a solution fast - i gave him one.

I had same problem with a couple of long cable runs, worked fine with laptop but no good with PC with integrated Gbit NIC. If you can't shorten the cable run then you may have to put another small switch inbetween to boost the signal. Theoretically you can run cat5e 80-100meters realistically its more like 40-60. If the cable you ran is stranded replace it with some good solid core, that will also give a much stronger signal.

slam a wireless usb dongle in f t w

thread over cut here

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Show the Network Connection Icon in the Taskbar. Right click on it and show Properties/Status. Click on the second tab page. Does it show a really stupid IP address that bears no resemblance to your LAN's? Are you using DHCP? If yes then the switch has locked the port you are connecting to to the laptop's MAC address of it's NIC and the switch's DHCP is failing to release it.

Usually even if you try a repair network connection in Windows it still won't relinquish. My router-switch's DHCP does this, very annoying.

You either have to patch the PC into a different port on the router-switch not currently being used so the Router-Switch recognises a new MAC address on a new port and assigns a new IP address from the DHCP reserved list and leases it to that MAC address, or assign the MAC address of the new PC a fixed IP on NIC powerup/switch recognition in your router-switch/server. It will recognise the MAC address and force DHCP to assign a valid IP address to it regardless which port it's attached to on the router-switch.

You should be connected then.

If this still fails it will most probably be hardware. Don't be surprised it's what I have said above though. I've seen it often on quite a number of routers now.

SFB; Your post completely f***ed with my head.

Is this a managed switch?

Thanks for all your replies everyone. Turned out patching it into a port on another switch got it working (not just another port on same switch as I had tried earlier).

In answer to some of your questions:
-No it is an unmanaged switch (well it probably has ability to be managed but this is not used)
-I ensured I was using straight-through cables (used a patch lead that worked fine on another datapoint)
-I didn't try with a short patch lead into the switch simply cause I'm lazy and didn't want to carry PC to data comms room. In hindsight this would have been a good troubleshooting step.

I'm hoping maybe the problem switch might just need a restart...I have more similar PCs arriving soon and no more ports on the switch that solved the problem :(

Again thanks for all your suggestions!

Yeah I'd restart the original switch you've plugged this PC in first as well. It could be that it's doing something dodgey like caching the MAC address of your PC's nic. Might explain why when you patched it to a different switch it worked straight away. I've had this problem before and thought it was cabling / dodgey termination etc but sometimes it turns out to be the switch acting up.

arp caching isn't exactly dodgy behaviour though ;)

no u