On Thu, 30 Dec 2010 15:06:31 -0500, Yousuf Khan
wrote:

Issue affects Windows 7, Windows XP, and Ubuntu Linux.

As of yesterday, my onboard Realtek Gigabit Ethernet NIC stopped working
fully. It's a "Realtek PCIe GBE Family Controller", model RTL8167. It
was the NIC built into the motherboard of my PC, which is an ASUS
M4A785-M. Initially, it wasn't working at all when plugged into my
router, so I plugged it into a separate hub, and it somehow got working
at the lowest possible speed of 10 Mbps. This NIC has previously worked
both at 100 Mbps, and 1 Gbps!

I also tried this under Ubuntu Linux, thinking maybe it's a Windows
driver problem, but the same problem occurs under Linux, so it's looking
like a real hardware problem. Perhaps it's an autodetect issue, is there
some way to hard-code it to run at 100 Mbps or 1 Gbps, without going
through autodetection?

Yousuf Khan

Under Windows Device Manager you can find adapter-specific settings that may
include the ability to force a specific speed. It won't fix a hardware problem
but it might be useful in diagnosis.

As for your specific problem, presuming you've eliminated the network cable
and any other external influences such that the problem is at or behind the IO
panel connector for the nic, one common failure mode - and frankly about the
only one a user has much chance of fixing in the field - is a solder joint
gone bad, which can often be diagnosed by gently flexing the connector body
while the nic is cabled to a working 100Mbit or Gbit port, and checking to see
if the status LEDs change state...

/daytripper