I've a D-Link DFE-520TX PCI Fast Ethernet card, which is/was excellent until this first problem. 2 nights ago there was some good lightning/thunders activity, resulting in burning of ISP network switches. This morning they replaced the switches and brought up the network, but here's the problem:
1) Under the default card setting with Auto-negotiation, PC looks for DCHP Server address resolution and ends up with YELLOW triangle in the system tray.
2) Whereas, when I CHANGE the card setting to 10Base in FullDuplex, then PC gets connected to the ISP network.
ISP support said that either the card could be damaged due to lightning strike or it could be due to damaged cable running from port box to the PC (RJ-45). I'm wondering, could lightning strike damage a Network card in such a partial manner (just one feature, i.e., Auto-negotiation)?
But that person warned, there will be deterioration in ISP speeds when I use 10Base in Full Duplex (for now) compared to Auto-negotiation speeds. Speeds really came down badly, that's understood.
Main question is, Auto-negotiation card mystery? I'm not sure if the problem in the card or in the Internet cable.
Power surges, brownouts, and blackouts can cause some pretty exotic behavior in electronics, so I don't doubt the card can be semi-functional. Just to wrap up loose ends, you night want to try a different network cable. A miswired or crimped cable can cause these type of problems too. Yes, I know you have probably been using that cable for a while now with no problems, but it can't hurt to check.
They changed the cable in the morning. Also I ran these tests:
1) Plugged the same cable into a Laptop, connecting with default setting, Auto-Negotiation, was successful and done the bandwidth testing too (13 Mbps DL and 11 Mbps UL).
Note that in PC the Speed test fails!
2) Next, rebooted into that PC in Fedora Core 14. Detects the card, here's dmesg:
[ 19.572814] via-rhine.c:v1.10-LK1.4.3 2007-03-06 Written by Donald Becker
[ 19.572932] via-rhine 0000:01:05.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17
[ 19.848539] eth0: VIA Rhine III at 0xefdfff00, 00:15:e9:48:b1:a4, IRQ 17.
[ 19.849260] eth0: MII PHY found at address 1, status 0x7869 advertising 05e1 Link 45e1.
[ 36.193877] eth0: link up, 100Mbps, full-duplex, lpa 0x45E1
But, Internet doesn't work!!
So evidently, Network card's Auto-Negotiation gone kaput? I fail to understand how come a single feature makes card useless, though I'm typing here by using the same card in 10Base FullDuplex mode.
Anyone provide some insight? I think changing PCI slots test is useless?
Knowledge is good, but in this case, I don't think you will get a definitive answer. I've experienced exotic problems due to power problems in the past and on more than just computers . A UPS on the system almost always takes care of these issues.