Troubleshooting: Ethernet Problems - DHCP Failure & Static IP’s Don’t Work
Posted 4 months, 2 weeks ago at 10:21 pm. 25 comments
Ok, so the title is massive but still it’s about the best description I can give for this very strange problem. I was playing GT5: Prologue & had this computer on but it was in low power mode, you know, Monitor off, hard drives not spinning. When I went to use the computer again I noticed my internet wasn’t connected anymore. I use a ethernet adapter that is built into my motherboard and it has always served me well until now. Here’s the strange bit.
I noticed that Vista was desperately trying to connect (I use my routers DHCP rather than a static IP) but was failing and assigning the dreaded DHCP error IP address. I can’t remember the IP address it kept assigning but it wasn’t a standard router IP such as 192.168.x.x. As you might know from a previous tutorial I dual boot with Windows XP SP3 so I load up XP hoping it’s a driver problem in Vista. No such luck, as XP does exactly the same thing.
I jumped back into vista, I feel it’s network support is better, and tried a static IP. Still nothing. Maybe my cable has broken, so I get out my laptop which has Ubuntu installed on it, connects the ethernet cable, instant internet. This was when I started getting annoyed, why? Well no matter what I tried, the ethernet port checked out ok. The cable checked out ok. Yet the computer wouldn’t access other computers over lan, or the internet. I couldn’t understand what was going on and assumed that somehow my ethernet ports were dead. The hardware itself seemed in full working order but no matter what operating system I used it still failed to get an IP from DHCP or connect via static IP.
I decided to go into my local computer shop where I go to bounce ideas off one of the techs there which usually helps me a lot. So he tells me that if they are broken it isn’t really worth sending the motherboard back to ASUS, its a P5N32-E SLI, if I can’t prove beyond doubt that they are broken. If ASUS find nothing wrong they will charge you for the trouble, so just buy a NIC card. They are cheap enough. He then says to try this first, reset your CMOS. You can either take out the motherboard battery for 24 hours or use the jumpers on the motherboard, just look in your manual.
So I get home and move the jumper on the motherboard, I already knew how to do it, to the 2-3 position and then switch the computer on. I go into the BIOS and it seemed to have reset, so I hold the power button to switch off the computer. I then move the jumper back so that it doesn’t reset the BIOS again and switch it back on to go into the BIOS. I set everything back up such as boot order & overclocking settings. I then save the settings & restart the machine.
Success, it’s back. Yes, that’s right it came back from the dead. After looking all over the internet I found this problem a few times & it always seemed to spell D-E-A-D for the ethernet ports. So if you have these symptoms:
- DHCP assigning odd IP addresses
- Static IP also not working
- Formatting will not fix the problem
- Problem persists regardless of OS used
If you have tried all software solutions & it seems to point to hardware then try theCMOS reset. Usually the jumper is located near the bottom right of your motherboard but PLEASE consult the motherboards manual or online manual if you don’t have a physical manual. If you are really unsure then don’t attempt it and ask your local computer repair shop to have a look instead.
Please remember this is my experience and it may not work for you but if you are as desperate as I was then it’s probably worth a try. Just remember I am not responsible if you break your motherboard when trying this, not that I’m sure you could. Here are a few tips if you are going to try it:
- Use a anti-static band or earth yourself using a grounded object before hand, something like a radiator should do.
- Try not to touch any of the sensitive areas of the motherboard
- Be very, very careful when inside your computer as one slip…
Now that may look frightening but don’t be too scared. 
Those who are tech savvy and already know all that, give it a go and I hope it works for you.
As in all of my posts if you have any questions or need any help please drop me a comment and I will help you in anyway I can.
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Thanks a lot for your message i was almost giving up.
Greetings Abe
Hi Abe,
Glad you found it to be useful. I don’t think it has happened to many people but it’s quite horrifying when it does.
Thanks a lot. This saved me at least an hour trying everything else in the book, as usually flashing my bios is the ultimate last resort. Looking the problem up on the internet usually gives the wrong impression that it might be driver related, as suggested here:
https://bugs.launchpad.net/ubuntu/+bug/136836
But really it’s just a crappy Asus bios.
Cheers!
No probs. Glad it solved your problem.
Wow. I was racking my brains over this exact issue on my rig. Vista-64, p5n32 (Asus), Q6600, 2G PC-6400, EVGA 8800gtx.
Was unable to establish any connectivity past the local nic after a reload of the OS. Never even occured to me to turn it off and let it sit.
Thank you for publishing this info.
~V
Wish I had found this article earlier.
Hi Veah,
I’m glad you found the article of some use. It’s quite a nasty surprise when your on-board NIC just stops working.
I never found out what caused the problem. If anyone has any ideas I’d love to hear them.
Hi,
I’m also facing the same problem. unable to get the dhcp ip from my broadband modem. if i connec the same cable to other pc internet is started working fine. I have tried 2 to 3 network cards with different make.
What could be a problem.
Thanks,
s.s.arvindhar
The problem could be what I mentioned above. For some reason the BIOS is stopping your ethernet ports from working.
I didn’t try a NIC card when I had this problem but with it being connected to the motherboard it may stop that from working too.
Just try the CMOS reset by finding the jumper on your motherboard. Please wear a anti-static wrist band when working inside a computer, or at least discharge any static by touching an earthed metal object such as a radiator.
You should be able to find instructions on how to use and find the jumper in your motherboard manual.
Hope that helps.
Hi…
thx for sharing your info on this problen.
I have same Mobo and had same problem…
Started after installing the nForce driver package from nvidia.
I forgot to exclude the NAM from installation, and when I tried to uninstall i had a power shortage in my house… When i turned on the computer I could not reconnect the network.
tried formatting and reinstall vista… no luck..
installed anoother NIC, and got a conection. But since i run a GBit LAN i wanted it to work…
so tanks a lot
No problem Kasper glad you found it useful.
I’ve been working on/with computers for over 10 years. I had the exact problem you described with Vista just not grabbing an IP from the DHCP server and ended up taking all the same steps you did, I logged onto my laptop to order a PCI NIC and then found this post. I saw that you reset the CMOS via the jumper (I had already tried entering the bios to no avail). I reset with the jumper and boom, my internet is back. Not only have you saved my sanity (and a few bucks for a new NIC), it’s nice to come back to the hardware roots and fix a problem. I must have spent over 6 hours playing with drivers/reinstalls/OS rebuilds, but it’s finally over!
Hey SniperD,
No problem, I just glad people are finding this post of some use. I must admit it was kind of a baffling moment for me when it just seemed to die.
I agree it makes a change to have to actually go back to the hardware rather than mucking around with drivers and OS’s.
I don’t know if this is relevant to you but I actually found the cause of my problem. It turned out to be Vista’s sleep mode. For some reason dropping into sleep, even the my computer is definitely sleep compatible, will completely disable my ethernet ports.
I never realised that the computer had went to sleep and woke itself back up, how I don’t know.
Anyway I’m rattling on, glad you fix it though.
Thank you very much, it helped me a lot. I was in the same situation. Clear CMOS was the solution.
Cheers.
Keep up the good work.
Glad it worked for you.
is there any way to use different computers to access the internet with the same ip no matter where you are ??
I subscribe to a stock trading service which suspends my membership every time I use a different pc
I don’t think so. You can use different computers in the same house if you are on a router because the router has the main ip address. Using a computer from anywhere would require you to make the computer you normally use a proxy so that you can connect through that pc.
You could however use VNC or remote desktop to connect to the PC with the IP you normally use and then connect through that. You could even set Wake On LAN so that your computer would wake up when you try to access it via VNC/RD however this tends to be quite hit and miss, mostly because your computer will wake up at any sign of LAN access, well mine does anyway. It’s something you might want to try, it’s generally in the BIOS.
As for VNC programs you can use Vista’s Remote Desktop if you have Vista, or there are free alternatives such as TightVNC or there is a free windows version of realVNC. Just do a google search and you’ll get quite a few.
I hope that helps you a bit.
Good luck.
Hey thanks for this post. I too was baffled by this problem on my p5n32-e sli plus, and I too found this problem after waking from sleep mode. I was beginning to thing the ethernet ports had died somewhat - however the chances of both going at once is quite high, so I kept searching.
Anyway I will give this a try as I meet the criteria you mentioned, just too tired atm so tomorrow it is!
Hey ComaXS,
I have managed to fix this problem completely now and I can now use sleep mode without any problems.
After you have used the method I described to fix the problem you can stop it from happening by upgrading your motherboard BIOS.
I’m going to assume you don’t know how to upgrade but if you do just disregard this and download the latest BIOS update from ASUS’s website.
ASUS BIOS Update 1003
Please remember that these are generalised instructions and that you should refer to you motherboard manual for more detailed instructions. Also please be very careful. Most BIOS & CMOS systems have protection & backup features but if the power fails or something happens during the update it can totally brick your motherboard.
Generally though, especially when using ASUS’s EZ Flash utility it’s very very easy and painless to do.
I hope that helps you, and soon you may be able to use Vistas sleep mode, which does come in handy.
Its always good to assume someone doesnt know how so no worries there.
And I have to say thank you so much the problem was 100% as you described. I will try upgrading my bios and testing that out. Now that I know the issue, im not necesarily so concerned - I may just avoid sleep mode for the time being anyway. Theres no practical use for it anyway as my desktop is purely a gaming rig.
Also did you realise that ASUS update can be used to flash the bios from within windows?
I’m glad that the problem was the one I had described, at least you know how to fix it if it does happen again.
Yes I know you can use the ASUS update utility to upgrade from windows but I don’t really trust windows to be stable enough while it’s updating. I’m probably just paranoid but I prefer to do it from inside the BIOS itself. Then at least the only thing that can go wrong is a power failure.
Oh and thanks for visiting my site.
I had the same problem on a new p3n32-e sli mobo that I got replaced under warranty since my first board dided, and took out my 4 gig of ram on one of my 8800gt sli, but ill know that after I tested it to night.
I did eveything, I finally go it back after I installed a wireless nic into my system and my onboard started working again last night, I even reset my router. But I’ll remmeber to try the reset the bois if it happens again. I find this mobo to be really fragile, and you have to strip it down to bear bones just to get a stable install of Vista.
I’ve never really had many problems with my mobo apart from this NIC problem, so it looks like ASUS learned from their mistakes, thank god.
Usually hard reseting the BIOS is a last resort but if nothing else works it’s always worth a try.
Luckly though as I mentioned before, ASUS released a BIOS patch for my mobo to fix the NIC problem. So if you have a problem like that one please check your mobo manufacturer for a BIOS update.
Yes!!! When I was reading your post and nodding my head, I was hoping that a solution was there and it indeed was!
After reformatting, reinstalling windows and all sorts of stuff, they still weren’t working.
Thank you very, very much for sharing this with us. I owe you a massive pint!
Tom
No problems Tom I’m just glad that my little blog post can help other people with a problem that haunted me for weeks.
Oh and as for the pint make it a Fosters.