Cannot obtain an IP address through DHCP.

Discussion in 'other software & services' started by Close_Hauled, May 29, 2005.

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  1. Close_Hauled

    Close_Hauled Registered Member

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    I am getting the following error message on startup on my XP system:

    My computer cannot obtain an IP address for either of it's two network cards from my ISP's DHCP server. One card is and Intel Pro/100 VM, and the other is a Netgear WG311. Both network cards have the yellow yield sign with the exclamation point saying that the status is "Limited or no connectivity". My laptop connects to the router just fine, both wired, and wireless.

    Initially I thought that this was a physical problem. I added the wireless card as part of my diagnostic. Originally the wired card failed to connect. I swapped out the cable and it still failed. I added the wireless card and it failed too. If I assign an IP address to the wired card, then the physical connection is good. Any ideas, or recommendations would be helpful.

    So far I have tried "ipconfig /release", "ipconfig /renew", and "Repair" in the connection properties. I have tried re-installing the drivers. I have tried rebooting the router (not that I think that the router is a problem since the laptop works through it).
     
    Last edited: May 29, 2005
  2. Paranoid2000

    Paranoid2000 Registered Member

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    Was your computer previously able to obtain an IP address via DHCP? If so, then it is likely a configuration change (with the router setup or any software firewall you are running) that is the cause. If you are using a new network card and have configured MAC filtering on your router, then this is a possible cause too - the card will have a different MAC address which needs to be added to the router's filter.

    However if you know the IP address your router normally assigns your PC, then you can configure your network card to use that as a static address and dispense with DHCP altogether.

    Network cards should have activity and link lights as should your router, so you can confirm that the cable is working (link lights up, activity blinks). Wireless adds extra issues though (reception, encryption) so it is best to stay with the cabled card for troubleshooting.
     
  3. Close_Hauled

    Close_Hauled Registered Member

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    I am way ahead of you on this. I assigned the computer an IP address and I am using it now.

    The addresses are assigned by the ISP's DHCP server. I do not have a normal configuration. I am using the router as a switch, not a firewall/router. My connection to my ISP is a direct wireless connection. Quite unique.
     
  4. Close_Hauled

    Close_Hauled Registered Member

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    Another thing that I forgot to mention was that I tried to set up an ad-hoc peer -to-peer network between the laptop and the broken computer. The DHCP problem still exists. The desktop sees the network, but cannot obtain an IP address.
     
  5. Paranoid2000

    Paranoid2000 Registered Member

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    If you are getting addresses from your ISP's DHCP server then maybe they are restricting you to one address? (test this by disconnecting your laptop and seeing if your desktop can then connect). It would be far better to enable Network Address Translation on your router (if available) and use it as a DHCP server to avoid such constraints.
     
  6. Close_Hauled

    Close_Hauled Registered Member

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    Tried this this morning. The desktop was the first computer that I turned on. I can test this again with the laptop's multiple network cards.
     
  7. Paranoid2000

    Paranoid2000 Registered Member

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    Just to repeat a previous question - has your desktop ever been able to get an IP address from your ISP?
     
  8. Close_Hauled

    Close_Hauled Registered Member

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    After further review, I was able to figure this one out. Where I got fooled was with the difference that Windows 2000 and Windows XP handle DHCP failures. Winows XP reports the failure, while Windows 2000 does not. My laptop has Windows 2000 and it "appeared" to be connecting just fine on all of it's network adaptors, when in fact only the wireless connection was working. The DHCP server was assigning addresses to the wireless card only. Apparently it has locked onto the wireless cards MAC address

    When I first found this problem, it was 2 o'clock in the morning, so my troubleshooting skills were not at their sharpests. After going over the problem the next day, and being more efficient, I was able to discover the problem. Now I just need to call my ISP.
     
  9. Paranoid2000

    Paranoid2000 Registered Member

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    Interesting - Win2K has reported past DHCP failures for me but only in the Event log. At least this gives a better idea of the exact cause, so thanks for the update.
     
  10. Close_Hauled

    Close_Hauled Registered Member

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    Windows 2000 reports the errors in the event log. It's the connection icon that is different. Windows XP shows a yellow yield sign with an exclamation point, Windows 2000 shows a normal connection.
     
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