Strange LAN failure: what possible cause?

1

My home machine is intermittently failing to send data (via ethernet) on my LAN. There is a 4 port wireless router, with 3 other devices that are working fine. I've tested two of them with ethernet (normally they use wifi), and that's fine too. Normally all IPs are assigned by DHCP in the 192.168.1.x range.

Symptoms I have seen:

  • Reports of IP address conflicts on other devices (bizarre in itself, because this setup has been stable for months)
  • XP reporting "limited connectivity" (ie, the same as when the network cable is completely disconnected)
  • The router showing "incomplete" as the ARP status for my machine.
  • After statically assigning an IP, getting "dynamic" as the ARP status, everything looking normal...but total inability to communicate with anything else on the network (or beyond).

And then, sometimes it's completely fine. (It fluctuates over a period of hours.)

In other words, various levels of connectivity between zero and perfect.

The only explanation I can think of is that my NIC (integrated into my 5 year old motherboard) is dying. Otherwise I would like to blame the router, but it seems to be behaving itself. I have tried using different ports.

Wondering if I have overlooked anything. Any other tests I can try? Suggestions?

Steve Bennett

Posted 2011-03-20T12:38:48.743

Reputation: 1 458

To add more weird symptoms, I just set the connection back to use DHCP again. The router reports that it assigned it 192.168.1.3. XP continues to report no IP address for a minute or so. Then, suddenly a bubble pops up saying the network connection has been established...and ipconfig /all starts reporting that it has automatically been assigned 192.168.1.150! (That's the address I was previously assigning manually.) Bizarre. – Steve Bennett – 2011-03-20T12:45:35.820

Please read our FAQ, this problem is more appropriate for our sister site superuser.com – Chopper3 – 2011-03-20T12:55:00.413

Thanks - the scope of serverfault wasn't quite what I thought. – Steve Bennett – 2011-03-21T01:11:45.180

Answers

1

The advice given here worked: http://forums.whirlpool.net.au/archive/941798

Probably my TCP/IP stack was broken, and WinSockXPFix fixed it.

Steve Bennett

Posted 2011-03-20T12:38:48.743

Reputation: 1 458