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InterviewSolution
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Solve : Sudden, and issolated network failure? |
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Answer» I've been a long-time lurker on tech forums, and have had wonderful success in correcting any deficient behaviour a machine might unwisely demonstrate, until today.
And now the BACKGROUND: The above machine is one of three (sometimes four) machines that share a DSL CONNECTION courtesy of a Linksys router. And up until today, there has never been a problem accessing the internet from it. Upon discovering that the machine was not resolving any network hosts, I set about trying to find the weak link in the network chain. I booted a second machine to see if our network access was down in general; it was able to access the internet, so it wasn't our ISP. Next I booted into Slackware thinking it might be a glitch in Windows or one of the drivers, but such was not the case, as the problem persisted across party lines.Next up was the router and cable. I pulled the ethernet cable from the back of the box, plugged it into a laptop, booted it, and discovered the internet was still working. So the cable is good, and the router did not suffer a very selective failure. Thus I figured it must be that the on-board NIC had failed. So I pulled the (working) NIC from another machine, and installed it in the patient. After DISABLING the on-board NIC, and installing and enabling the drivers for the D-Link, I was still unable to access the internet. One reboot later (I was desperate at this point) the problem remained stubbornly unresolved. Finally I tried a Linux LiveCD (Knoppix), but despite all my finger crossing, and please, even it couldn't get the machine online. After several hours of trolling the internet in search of answers, I am left with the question of just what has gone wrong? At this point I'm not sure if it's a network problem, or a hardware problem (possibly elsewhere in the system),and I'm not sure at this point how to diagnose the problem. Thus, if someone here happens to have even the vaguest of notions as to what might be wrong, I'm all ears. well, like you say, it's somewhere in the chain- it could be the router- as in ethernet port itself. (wiring for the port, etc) OR- a software problem. does the computer even get a Ipaddress from the router? Does it say a connection is unplugged? BTW: whata coincidence! I just finished installing that exact D-Link NIC! Quote it could be the router- as in ethernet port itself. (wiring for the port, etc) This was one of the first things I tested for. I grabbed a laptop running FreeBSD 7.0, and using the same port (and same cable--two birds with one stone), I hooked it up. After boot, the machine had immediate access to the internet. So the router and cable seem fine. Quote does the computer even get a Ipaddress from the router? Based on the above, I'm going to say that the router successfully passes ipaddresses, and the NICs (or at the very least, the D-Link, given that it worked on the previous machine it inhabited), receive them. Quote Does it say a connection is unplugged? Under Windows I get a status of: Limited or no connectivity (I've come to loath those words). I also get the following for ipconfig for the D-Link: Code: [Select]Windows IP Configuration Ethernet adapter Local Area Connection 2: Connection-specific DNS Suffix . : Autoconfiguration IP Address. . . : 169.254.22.44 Subnet Mask . . . . . . . . . . . : 255.255.0.0 Default Gateway . . . . . . . . . : And similar messages under linux (again, for the D-Link) for ifconfig eth1: Code: [Select]eth1 Link encap:Ethernet HWaddr 00:1e:58:aa:56:cc BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) Interrupt:20 And dhclient eth1: Code: [Select]Internet Systems Consortium DHCP Client V3.0.6 Copyright 2004-2007 Internet Systems Consortium. All rights reserved. For info, please visit http://www.isc.org/sw/dhcp/ Listening on LPF/eth1/00:1e:58:aa:56:cc Sending on LPF/eth1/00:1e:58:aa:56:cc Sending on Socket/fallback DHCPDISCOVER on eth1 to 255.255.255.255 port 67 interval 5 DHCPDISCOVER on eth1 to 255.255.255.255 port 67 interval 14 DHCPDISCOVER on eth1 to 255.255.255.255 port 67 interval 10 DHCPDISCOVER on eth1 to 255.255.255.255 port 67 interval 9 DHCPDISCOVER on eth1 to 255.255.255.255 port 67 interval 13 DHCPDISCOVER on eth1 to 255.255.255.255 port 67 interval 10 No DHCPOFFERS received. No working leases in persistent database - sleeping.What a difference a day makes. For some (as yet unknown) reason, the on-board ethernet port as regained full functionality under both Windows, and Linux. The problem has corrected itself. I don't know how, or why, but I'll TAKE it, THOUGH I'm not holding my breath that this recovery will last (this particular machine has had numerous curious, and obscure problems in the past). As to a diagnosis, I'm still interested in any ideas people may have. I like my mysteries solved--call me old fashioned. |
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