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Why do I keep losing my network connection?

My office is connected via a LAN. My system has a strange problem: I frequently lose my network connection on my computer. When this happens, however, I am able to ping the network. To restore the connection, I am forced to restart my machine. Can you help?
Sorry to hear about your system issue with network connectivity. Before we get started with troubleshooting, you will need to confirm if the issue is a global or isolated one -- that is, are other users experiencing the same network problem or is the problem only occurring with your computer. Next, check the system's logs...  to spot any errors on your system before, during and after the network interruption and system restart. If no errors exist, consider the following steps while keeping track of the frequent intervals before each reboot is required. In particular, record (1) what applications and processes are running at the time that the network connection looks like it's down and (2) the system performance state. Since it appears that your system -- doesn't matter whether it's a Windows, UNIX/Linux, or Mac OS -- upon a fresh reboot is fully operational, the issue does not appear to be with the network jack, cable or network interface card (NIC). If by "frequently" you mean the issue occurs at close intervals (e.g., every five minutes) then the issue has to do with a faulty or misconfigured NIC, corrupted NIC driver or TCP/IP software, or corrupted Registry and/or OS. Otherwise, the problem is due to faulty or insufficient memory, an errant process, or Trojan horse or virus. Make sure that you are running anti-virus software and that it is updated with the latest engine and signature file. Before proceeding, make a backup of your system.

Here are some troubleshooting steps:

1. Check system configuration and TCP/IP settings:

  • Make sure subnet mask is correct.
  • Make sure DNS servers exists.
  • Make sure default gateway is correct.
  • Check DHCP server for duplicate IPs.

    2. Run full system diagnostics:

  • Inspect memory.
  • Inspect network adapter.
  • Inspect motherboard.

    3. Run full anti-virus scan:

  • Get latest engine and signature.
  • Perform full scan.

    4. Connect system to another network jack and use working cable:

  • Connect system to another switch port.
  • Test connectivity from another area.
  • Connect another system in your area.

    5. Uninstall and then re-install network card driver from vendor's Web site:

  • Make sure you select manual location and specify drive folder.

    6. Replace NIC with working NIC and put old NIC in another system and try to reproduce issue.

    7. If you have a built-in firewall, temporarily disable it and see if issue stops.

    8. Uninstall and re-install TCP/IP software from original.

    9. If using Windows OS, uninstall and re-install Client for Microsoft software.

    10. Re-apply the latest service pack.

    11. Re-install OS and apply service pack.

This was last published in September 2004

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