"limited Or No Connectivity" Driving Me Nuts!, ip address problem Options

[jammyk]

Hi all, it's been a while since I've needed to post on here but now I'm back with what has got to be my most frustrating problem ever. Here goes:

I'm at university, living on campus during term time and at home in the holidays. My PC and laptop both travel with me back and forwards from home to uni. My laptop is fine all the time wherever I am, old and cranky, but working. My PC is fine on my home network but has some Issues (the capital letter is justified I think) with the campus network that have both myself and the IT services guys here on campus completely stumped, these started back in october and it's been a pain pretty much ever since.

A bit of background info first:
The home network: maximum of 7 machines at once. A mix of PC and laptop, wireless and wired. All sorted out in the most simple way possible with a wireless adsl router dishing out DHCP to all machines (obviously with the relevant network encryption on the WLAN)

Uni network: campus wide - thousands of machines all running on DHCP dished out by servers throughout the uni. the only changes I had to make to my setup upon arrival were to change my computer name to avoid IP conflicts and to connect to the internet through a webcache.


When I arrived my PC worked fine and conected to the network with no problems, but after about three weeks it wouldn't connect at all - it wasn't picking up an IP address. I couldn't fix the problem but I discovered a workaround for it, I had a marvell lan chip and the cable tester software that comes with these chips seemed to temporarily fix my problem. Every time I started the machine I ran the cable test then plugged in the lan cable and it worked.

Next my motherboard blew up, by the time I got a replacement I was home for christmas and with a windows repair my machine was working fine again (even though I'd changed chipset, audio chip, lan chip, the works) with no network problems. When I got back to uni I had no connection again so I re-installed windows from scratch and the machine was fine again.

Yesterday it stopped recognising my network card and wouldn't find my USB - LAN adaptor either when I plugged it in. I ran a windows repair in the end and it now finds both my on-board and my USB adaptors but again it won't recieve an IP address.

I've changed the cable just in case, my laptop works fine and no-one else in the block is having a problem so I'm confident it's a problem in the machine somewhere. I've uninstalled my antivirus and all software I could think of that might access or in any way modify the network settings to no avail. I've flushed the DNS cache, reset both the firewall and the winsock catalogue, and checked all three boxes are ticked under authentication settings (use smart card, authenticate as user, authenticate as guest).
I've uninstalled the network adaptor and reinstalled it with the latest drivers from the marvell website (yes, by some fluke I've ended up with a different marvell chip on my new M/B). I've tried my previous workaround and checked the hosts file just to be sure (though I can't see how that could stop me from getting an IP).

After a motherboard change and clean install of windows I can't see how this has resurfaced, and I'm lost as to how to solve it. I've tried the campus tech support but they're as confused as me and as they quite rightly point out: it's not their problem and they can't waste too much time on it (they've been very helpful but there are limits). Please help me

James

[PolishPaul]

Hmm, now that's a good one...

So what's the output of ipconfig /all ?

Have you tried assigning a static IP for yourself? (may be tough on campus network without conflict)

We need to approach the problem methodically as it seems this is one that's been on your back for a while. First, keep notes on everything you did(do) and the outcome. Divide the problem in half and test. So for example -

Test it away from the school network. Borrow a typical router/switch (buy?) and just setup a connection to it. See if you get DHCP etc. This way we divide and conquer, so if it works, its most likely the school.

Another test, try a different computer in the same connection. Are there other PC's in the room? Do they work? Will they work on your cable?

Its quite possible that the network cable on the other end is faulty.

One you eliminate that half (you vs network) continue to split the remainder and test. Rinse and repeat. Eventually you'll narrow it down.

Another thing that may help, is if the IT guys tell you what the gateway IP and the DHCP server (possibly the same IP) address is and the netmask for the network. This way we can try a static IP that would work and do some basic network testing. Additionally, you can look this info up on your rommmates/neighbors PC by using the ipconfig command.

But for starters, do a controlled test with a different switch (your PC -> router) to see if you can catch DHCP. Then try another PC on the same school network to see if it can connect.

[jammyk]

Hi Paul, this is the result of my work today.

before I started today I reset the winsock catalogue, firewall, dns cache, and rebuilt the ip stack to make sure i had default settings (though i'd odne everything but the ip stack last night as well)

I have my laptop here which works fine on the same connection, which would suggest a pc problem as the wall socket and cabling is obviously fine (I have tried with the same cable I'm using for my PC)

I borrowed a router and first conected my laptop to it with no issues, the router was dishing out DHCP fine. I then tried my PC, interestingly the onboard lan didn't pick up an address but the usb-lan adaptor worked (neither of them have been working on my network port in my room).

Next I ran a lan cable into the room across the hall from me and tried connecting to the campus network through the port in there. Again my onboard didn't work but the USB one did.

Lastly I tried the port in my room again connecting through my USB adaptor - still nothing.

This is suggesting to me that I have a problem with my on-board lan, but there may well be an issue with my account on the server as well (the campus network requires you to enter your username when you first log on through a particular port and logs your MAC address and PC name as connecting through that port, saving all the details against your username in case you do something naughty while you're here) I'm going to try and get the tech guys to reset my entire account on the network and see if that sorts the port issue. I'll let you know how I get on.

In the meantime I'm still trying to figure out what's happening with my onboard lan, if you have any ideas I'd be really glad to hear them.

thanks for the help you've already given,

James

[PolishPaul]

Hey James,

Well, you've narrowed the problem down some more, so lets keep going. One thing to keep in mind as well, is to try to change 1 variable at a time and record the results.

Have you been able to get the network information (netmask, gateway) from the school? This way we can setup an IP manually and see if things work (you can find a free IP and assign it manually). What is the output of ipconfig /all in each situation (working and not, laptop and PC) - don't worry this info is on an internal network so we can't do anything bad with it

One other thing you may wish to try is another NIC - you can usually pick up some cheap ones for 10-15$ or even less if you shop around. (hardware vs OS/drivers)

I would also follow up with the school and your account. Could it be your MAC address is not allowed on the network? This seems unlikely however with the new mobo...

Now, are the drivers correct for this system? Have you downloaded the latest ones? Is this a 64 bit system? Download a Knoppix CD (or pick up an Ubuntu live CD in a news stand) and boot from this CD. You can then see if the NIC works on that system (with router, school and/or manual IP). This way we can further split the issue in half (drivers/os/viruses or else). This would be a very helpful test and it will not touch your hard-drive, it will run Linux from the CD in your memory.

Check out the device manager as well, anything in the properties for your NIC? Definitely check out the event viewer for warnings and errors (application and system logs are most likely the place).

Also, what system are you running? Windows? what version? service pack? updates current?

Re-reading your original post, i get a taste of incorrect drivers in my mouth I'm totally jumping to conclusions now, so lets get some more info on your system.

One more thought just jumped into my head... How experienced are you with hardware and system installs? It sounds like you may be using the OEM Recovery Disk but with a new motherboard? After you replaced the motherboard, it has new components like you mentioned earlier. If you've used a recovery CD and re-imaged your system, you may have incorrect chipset and NIC drivers. Lets get those details from you and we'll see where we stand with the OS and drivers.

This post has been edited by PolishPaul: Feb 24 2009, 08:17 PM

[jammyk]

Ok, firstly I've found a workaround for the problem (i'll tell you about that in a sec). I thought I'd answer a few of your questions first to try and help anyone else who comes across this issue:

ipconfig hasn't been showing anything out of the ordinary until you renew IP, at which point it says the DHCP server isn't responding.

it's not a driver issue, i've tried the latest drivers from both the motherboard manufacturer site and the network chip manufacturer site to no avail.

I've been building, selling, and fixing PCs at work (in a computer shop) for the past 4 years, with 6 months out working on an IT helpdesk, this pc was built from scratch and as such uses a standard XP disk, not a restore disk with built in drivers so everything on the clean install was as it should be. Also I don't allow any extra programs to run in the background so the only thing attempting to control the LAN chip was XP Pro itself (unlike on some packard bell/HP/compaq machines where teh auto setting is to use alternative software).

It would appear I was dealing with 2 problems simultaneously: I found a diagnostic program for all marvell yukon chips (http://www.marvell.com/drivers/driverDisplay.do?driverId=136 is the download link for the latest version at the moment) which runs various tests on the chip, some of which my pc fails so I may have a faulty chip there.

the second problem was the lack of ip address on my pc, this was happening only on this one port (not across the hall or in the tech workshop here on campus) and was an issue on both my onboard LAN and the USB adaptor I installed. My pc wasn't detecting the type of connection used (this port is limited to 10meg and is running full-duplex). I didn't know all the residential ports on campus are running at 10 meg so I couldn't fix it but I'll put up instructions on how to change from auto detect for anyone else who has this issue in future. This is for windows XP only, I havn't checked how to do it in vista yet:

Open device manager (right click on "my computer" and click "properties", then the "hardware" tab, then "device manager") ==> expand "network adaptors" if it isn't already expanded, then double click your adaptor ==> select the "advanced" tab ==> the settings are in the box entitled "property" and to adjust them change the option in the "value" dropdown menu. My problem was all to do with the "media type" property. ==> once you've made changes hit OK to apply them.

I must say I've never heard of these settings needing adjusting before, this seems to be an issue between my pc and the switch in my block.

Lastly, thanks for your help Paul, even if we didn't solve it in the end

James

This post has been edited by jammyk: Feb 26 2009, 05:43 AM