New PC crashes network?

[Mirith]

Hello!

I have a problem and frankly I'm running out of ideas now... I built a new (first!) PC a month ago (specs below in case you need them). Running Windows 8.

The PC is fine and I haven't had any problems with anything BUT when my housemates got back it turned out that they are having issues with the internet. After some investigation it looks like my PC is causing it. It's plugged into the router via a cable. I got us a new router, a new cable, assigned IPs to computers, all for nothing. My internet connection is fine, but it has been deteriorating for my housemates drastically. Also, if I switch off my PC it completely crashes the entire network for everyone else. They then unplug my cable, restart the router and all is fine for them. Till I want to use the PC/internet again...

Any ideas of what's going on?

CPU: Intel Core i5-3570K 3.4GHz Quad-Core Processor
Motherboard: Gigabyte GA-Z77X-UD3H ATX LGA1155 Motherboard
Memory: Kingston 16GB (2 x 8GB) DDR3-1600 Memory
Storage: Samsung 840 Series 120GB 2.5" Solid State Disk
Storage: Seagate Barracuda 500GB 3.5" 7200RPM Internal Hard Drive
Power Supply: Corsair Builder 430W 80 PLUS Certified ATX12V Power Supply

 

[lif_andi]

Might be a faulty NIC on your mobo... What's the NIC? What kind of router do you have? What kind of internet connection do you have ? Does it affect LAN connectivity (like can you share files even though internet crashes) ?

 

[yinan]

IP conflict? Bad cable?

 

[Mirith]

yinan, I tried different cables. Nothing is visible in the router log to indicate what's happening and there are no IP address conflicts because I've set static IPs for the computers, the network subnet mask is the default, then I assigned different IPs to different computers (above .1.60 if that matters) and the router IP is the default.

lif_andi, I'm not very tech savvy, so sorry if I get this wrong, but my NIC seems to be Qualcomm Atheros AR8161 (drivers up to date)and the router is Technicolour TG582n. The firmware installed is the latest one on the be website which is version R844J. We have ADSL internet.

I'll try to see if we can share files (don't normally do that since it's a bunch of housemates in one house), but as far as I can tell no, the whole network crashes and it kicks other computers off, as soon as the cable is unplugged the network becomes accessible again.

 

[lif_andi]

Try unplugging your computer from the network and get everyone's network up and running. Before you plug yours in, open Network and Sharing center>Change adapter settings>right click your adapter>status} Keep it open and plug your computer to the network. Your computer should start transmitting some data (send field) but we're talking under 10.000 bytes. If it goes over 100.000 very fast (like 5-10 mins or less, your NIC is likely faulty.

You could also install a program called Wireshark and start from the position of your computer being unplugged from the network. Run it and make sure no one is using the network in any way. There should be some traffic but not so much (you can see this in real-time with Wireshark). Plug your computer in and watch closely what happens. If everything starts to go crazy, particularly if you see a lot of 255.255.255.255 then your NIC is faulty and is generating un-needed traffic. Sounds complicated but really isn't, run Wireshark with admin priviledges and press capture, and that's it

If anyone else has a better suggestion please chip in, but this is all I can think of for now. Good luck mate.

 

[VirtualLarry]

ground loop problem?

 

[dawks]

Long shot, and even longer shot considering you said you were using static IP's, but is there a change Internet Connection Sharing (ICS) is running on your PC? With ICS, computers on the local network are configured to use the ICS server computer as the gateway. If that computer is turned off, all other computers loose their internet connection.

Rebooting the router (and having your computer off) may allow the clients to get their DCHP info from the router instead, which would mean they start using the router as their default and hence the internet starts working for them again. It could be that your computer is giving out DHCP faster than the router itself, overriding the routers DHCP.

Check Windows Services and make sure the ICS service is not running.

Or it could be a wiring/ground-loop problem as stated. I've had two Dell computers start showing an issue where the would not turn on with a network cable plugged in. Unplug the cable, and they boot just fine, then you can plug the cable back in and everything works normally.

 

[Mirith]

Try unplugging your computer from the network and get everyone's network up and running. Before you plug yours in, open Network and Sharing center>Change adapter settings>right click your adapter>status} Keep it open and plug your computer to the network. Your computer should start transmitting some data (send field) but we're talking under 10.000 bytes. If it goes over 100.000 very fast (like 5-10 mins or less, your NIC is likely faulty.

It's not possible to see that status when the PC is unplugged. But I checked it as soon as I plugged the PC back in and it's like it never zero-ed: I check before unplugging and then after plugging back in and it was pretty much the same, high 10,300,000+

I will get Wireshark too and check with that.

ICS is not running (not even possible to set it to run).

Would a ground loop problem affect laptops' wi-fi?

 

[ch33zw1z]

ideas:

-update router firmware and reset to factory defaults
-reinstall nic driver

-boot to Ubuntu Live and see if issue persists. trying a different OS will help isolate the issue to hardware or software. if the problem remains in a different OS, then it's not a driver issue, but most likely a firmware or hardware issue
- last but not least, in response to the previous step, install a expansion nic if you believe the NIC is actually failed in some way.

This sounds like a driver issue to me...

 

[lif_andi]

It's not possible to see that status when the PC is unplugged. But I checked it as soon as I plugged the PC back in and it's like it never zero-ed: I check before unplugging and then after plugging back in and it was pretty much the same, high 10,300,000+

I will get Wireshark too and check with that.

ICS is not running (not even possible to set it to run).

Would a ground loop problem affect laptops' wi-fi?

You could just keep it plugged in, disable it and then enabling it. The thing is you need to set the counter to zero to measure traffic. Simplest way is through Windows, Wireshark is a little more advanced.

 

[Mirith]

Disabling: up to 100,000 in 30s, then up to 260,000 within the first minute and then stayed around that mark.

I will try the drivers ideas. Not sure about Ubuntu, never did anything with a Linux OS, so would have to read up on it a bit.

Thanks for all the help, I appreciate it.

 

[ch33zw1z]

Disabling: up to 100,000 in 30s, then up to 260,000 within the first minute and then stayed around that mark.

I will try the drivers ideas. Not sure about Ubuntu, never did anything with a Linux OS, so would have to read up on it a bit.

Thanks for all the help, I appreciate it.

For Linux, there are "Live" disks. You create the LInux bootable media on either a CD or a USB drive, then you boot to it. It doesn't affect your current windows install, and you can test out networking to see if the problem remains.

From your description, the problem seems pretty consistent...maybe easy to rule out OS / driver issues quickly.

 

[lif_andi]

Disabling: up to 100,000 in 30s, then up to 260,000 within the first minute and then stayed around that mark.

I will try the drivers ideas. Not sure about Ubuntu, never did anything with a Linux OS, so would have to read up on it a bit.

Thanks for all the help, I appreciate it.

Ok, I think I miscalculated previously, but 26 Mbytes is a lot for initiating a connection. The important thing is that it stabilizes. Here at work I get just under 200.000 in the first 4 minutes, and I am working at a networking company so many services and whatnot. But since it stops and stabilizes its probably not a broadcast storm or something similar caused by a faulty NIC.

It's a weird problem you have. I don't see why other computers would drop out, unless your router or switch are misbehaving. Any chance you could get another device, like a small switch to test what would happen if you connect all your devices through that ? Just thinking you could find out if your central device is the one causing the problem by replacing it for testing purposes.

EDIT: Ch33zw1z also has a good idea with trying another OS on the same hardware, to see if it's related to software. My hunch is that it isn't, but it's certainly worth a try.

 

[drebo]

Turn off your torrent client.

 

[Mirith]

Ok, thanks for the info, will try a different OS - although the main issue is when I turn the PC off, so surely any OS will shut down in the same way during that time?

That's why I thought it was the router/cable and got new ones to check, but the problem persisted. Do you think I'd have to test with a different router/switch? As I said, I got a new router, but it's the same model as the last one.

I don't have a torrent client.

Oh, also, I just realised one more thing - I think that the internet drop is not instantaneous, I think it takes a few minutes (2-10mins) for the other PC/laptops to lose the connection (or maybe my housemates complain with a delay...).

 

[lif_andi]

Can't really imagine what could be causing this mate... Just so you know we're just stabbing in the dark here, trying to find ways to figure out what's wrong. Maybe your new PC is so powerful is keeps the whole network at your house running

Trying another OS is just an experiment, seeing if another TCP stack on another OS would do the same, if it did, then your problem is hardware or not on your computer, and if it didn't, that is if things would be ok on another OS, then it has something to do with your drivers or the TCP stack on your Windows setup.

Seeing that you've tried another router with the same results make it stranger still. My feeling is that it has something to do with electricity, like your NIC is sending a pulse at shutdown that messes up the other devices... but this would be strange. What happens if you put the computer to sleep?

 

[Mirith]

Can't really imagine what could be causing this mate... Just so you know we're just stabbing in the dark here, trying to find ways to figure out what's wrong. Maybe your new PC is so powerful is keeps the whole network at your house running

I know, and I appreciated all suggestions, it's nice to be stabbing in the dark with some help rather than all by myself And yeah, maybe I just build a supercomputer :biggrin:

When computer is asleep the network is fine. I mean there might be some glitches, like when it's on, but it doesn't crash.

Also, noticed yesterday that when I turn the PC off the NIC light flashes orange... I don't think anything is supposed to flash when the PC is off, so now I'm also considering build problems, maybe somehow it's still powered and so sending signals even when the PC is off. Hope it's not going to fry my mobo.

I did two things: switched it off at the mains and enabled ErP in BIOS. Then powered the PC, plugged it in, shut down and waited - the network didn't crash! Will see if the problem disappeared completely, at the minute it looks like it's solved... Would prefer to know what exactly was going on though.

 

[Mushkins]

I know, and I appreciated all suggestions, it's nice to be stabbing in the dark with some help rather than all by myself And yeah, maybe I just build a supercomputer :biggrin:

When computer is asleep the network is fine. I mean there might be some glitches, like when it's on, but it doesn't crash.

Also, noticed yesterday that when I turn the PC off the NIC light flashes orange... I don't think anything is supposed to flash when the PC is off, so now I'm also considering build problems, maybe somehow it's still powered and so sending signals even when the PC is off. Hope it's not going to fry my mobo.

I did two things: switched it off at the mains and enabled ErP in BIOS. Then powered the PC, plugged it in, shut down and waited - the network didn't crash! Will see if the problem disappeared completely, at the minute it looks like it's solved... Would prefer to know what exactly was going on though.

As long as the PC is *plugged in*, the onboard ethernet lights will be on when something's plugged into it. The motherboard still pulls a little bit of power even if the PC itself is turned off, and the NIC supports things like Wake on Lan and magic packets so it can be powered on remotely. Orange these days typically indicates Gigabit connectivity, and flashing just means there's activity.

Here's a question that hasn't been asked: whats the status of the other peoples PCs when the problem occurs? Is this only happening when they have all their stuff turned on and *then* you turn yours on? Does it not happen if someone else is out and turned their PC off? Do people have their phones and tablets and all sorts of stuff on the network too?

I'm thinking router/switch problems if "one more device" is causing the whole thing to come crashing down.

 

[Mirith]

Frankly, I have no clue, there are quite a few devices on the network at the minute, two phones, 2-4 laptops, 2 PCs. I can try and control them and see if I can notice some sort of pattern, but it won't be easy. I'm assuming though that it's my PC purely and simply because *every time* I switched it off the network crashed. The other devices must have been on/off in various combinations depending on who is in the house at the time and yet the network *always* crashed when I turned my PC off.

It has nothing to do with turning my PC *on* though. Plus there are fewer computers on at the minute than there were before I build this PC (summer, so fewer people around).

 

[Ketchup]

Is there any specific reason you are doing static IP on these? Probably the easiest way to narrow this down is to run to the store and get a cheap PCI NIC card. Something you can return. Whether the separate card continues/removes the issue should narrow down the cause a good bit.

 

[Mirith]

Yes, I was told that with non-static IPs the router might crash the network.

All seems to be working now, so whether it was changing the ErP or simply switching it off at the mains (maybe it is a build problem and there was some static build up or something?) it helped. I'll leave it for now as I'm flying abroad tonight and don't have the time to run around looking for a parts store that would allow me a return after unpacking the NIC.

 

[Ketchup]

Yes, I was told that with non-static IPs the router might crash the network.

I have never heard this. Was it because of a particular device on the network? My file server is the only thing on my home network with a static IP.

 

[ch33zw1z]

Yea, if DHCP is crashing your network...then you got a different problem.

 

[Mushkins]

Yes, I was told that with non-static IPs the router might crash the network.

All seems to be working now, so whether it was changing the ErP or simply switching it off at the mains (maybe it is a build problem and there was some static build up or something?) it helped. I'll leave it for now as I'm flying abroad tonight and don't have the time to run around looking for a parts store that would allow me a return after unpacking the NIC.

DHCP is plenty capable of handling less than a dozen devices. If DHCP is crashing the network, there's something seriously wrong with your router. Frankly, this is the first time i've ever heard of turning a PC off and the whole network going with it unless that PC *was* the DHCP server for some reason. If the whole network is going down, the router is where you should really be starting your investigation.

 

[Mirith]

Apologies for the silence, was out of the country.

Mushkins, I did start from the router - I got a new one and problem persisted.

At the moment everything seems fine and it has been fine since that BIOS setting change I mentioned.