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I posted here a while back about a problem pulling an IP from my router's DHCP on a Windows 7 machine. Since posting that message, I've taken even more drastic steps, but I still can't pull and maintain an IP from DHCP.

Sometimes, my computer will boot with an IP and keep it for a while (20-30 minutes). It will then lose the IP and end up with an automatic private IP (169.254.x.x). Here's a quick list of the key things I've done in troubleshooting.

  1. Swapped cables with a working computer (and rebooted the router)
  2. Updated NIC drivers on the computer
  3. System restore to a time when the computer was working
  4. Complete format and reinstall of Windows 7
  5. Boot from a bootable USB flash drive with a Windows XP install (Hiren's BootCD)
  6. Add PCI-E NIC (Intel NIC still can't pull an IP)
  7. Replaced Gigabyte motherboard via RMA (New board still can't pull an IP)
  8. Tested the rails on my PSU with a multi-meter

On the surface, this seems obvious that my problem is the router. I would just replace it if not for the fact that every other device in my house works with the same router. This includes several wireless devices, a couple of notebooks, and another desktop computer which also has a Gigabyte mobo with the same on-board NIC (Atheros gigabit NIC).

Here's the output of an ipconfig/all when it doesn't get an IP: ipconfig/all without an IP

Here's the output of an ipconfig/all when it does get an IP: ipconfig/all with an IP

I'm running out of ideas here. As far as I can tell, the next step is to replace this motherboard with an entirely different model. Does anyone else have ideas?

Update: My connection just went down again after working for a full day. I didn't use it for the entire day, but I did check periodically. Now, I can't pull an IP again.

I have disabled IPv6 for the adapter. I also ran some tests suggested by a commenter. Here's what I found.

  • I've manually configured what I believe is a valid IP. It's inside my DHCP range but not currently assigned to any client.
  • I'm unable to ping this computer from other clients on the network.
  • I'm unable to ping other clients from this computer.
  • I'm unable to ping the router from this computer.

Update: route print from the offending system: route print

route print from a working system: route print from a working system

Final Update: Hey, everyone. Thanks so much for your help. I've discovered the problem and wanted to share it with you.

I mentioned that I had tested the power supply with a multi-meter and all the rails showed proper voltage, but it seems that test didn't tell the whole story. On a hunch, I grabbed a power supply and swapped it in just to test. With the new power supply, I'm able to pull an IP consistently. I'm not sure if the rails are not consistently supplying proper power but they were when I tested or if draw on one rail from the components could cause another rail to dip. Whatever the case, it seems the power supply is the culprit.

Thanks for all your help!

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How long is the network lease? (e.g. does it loose the IP after half the lease time). Do DHCP REQ get send (use a network monitor tool on the problem computer or enable port mirroring on a switch. [Edit -scapt the lease time. 24H gets interesting after 12H and after 24H –  Hennes Oct 21 '13 at 12:42
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@raddevon have you tried another router? Try to borrow one from a friend, see if you get the same behaviour. –  Forza Oct 29 '13 at 15:17
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@EliadTech Oops. I shouldn't post when I've got the flu. I'm not thinking straight. –  Tonny Oct 29 '13 at 15:47
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@raddevon That second route print looks perfectly normal. The first one has that odd metric value and the persistent route that shouldn't be there (even though it isn't supposed to make a difference). Could you do a "route -f" command on the problem machine, reboot and then make a new route print ? –  Tonny Oct 29 '13 at 15:50
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@Forza Using a static address and pinging between machines (not the router) doesn't work either. That sort of excludes the router from the problem. On second thought... The build-in switch in the router might be flaky. Cleanest test would be to connect 2 PC's directly together, give them both a static IP and do the ping-test. That really excludes the router and it's build-in switch. –  Tonny Oct 29 '13 at 15:53

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