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Mike Caldwell
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Identify and enable second NIC card on a Ubuntu machine

I have a machine with Ubuntu 14.04 that my son set up for me to be a Plex server.  It has stopped connecting to the internet or even just the LAN. I verified the switch and cable by swapping in a CAT5 cable from another machine that sits right next to it and is working; no change.

I can see that this machine has a second NIC card port.  I have no documentation about the mother board.  I need an Ubuntu command to identify the MAC address of the second NIC card; I think when I have that I can set it up with the Network dialog box.
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Mike Caldwell

8/22/2022 - Mon
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Phil Davidson

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Mike Caldwell

ASKER
Thanks for pointing me in the right direction.  ifconfig showed only one ETH channel.  So I did open up the cabinet, get the MB model, and find the manual on line.  The "Integrated Peripherals" selection in the BIOS offered how to turn on the other ETH channel.  Did so, and Ubuntu really tried to get something out of it; it showed "Connecting" but never actually connected.  From the system diagram I have concluded that the PCI Experss bus must be shot, but to give this machine one more chance I'm going to pick up an outboard NIC card in the morning and see if that works.  If not, time to say goodbye to this MB.  Stay tuned for more!
sarabande

the BIOS offered how to turn on the other ETH channel.

it is not very likely that both internal MB ethernet ports were defective. are they flashing red? you didn't answer to Phil's question.

you better check the connectivity again and try to Exchange the cable, plug the cable into another port of your switch or router and check the connectors. also unplug the router or switch from power, wait some time, and replug.

Sara
Mike Caldwell

ASKER
There were flashing yellow lights.  I swapped in the same CAT5 cable to the same switch that another unit nearby uses; no change.  I then plugged in the CAT5 coming from the router to the switch directly to this unit; no change.  Ubuntu would show that ETH2 was "connecting" but then timed out.  That would imply an external problem, but with the swapping that seems to not be the case.  So my theory is that there must be a common point from the CPU to the serial channels is bad; both are on the PCIe bus.  So for $15 I can get a NIC card and give it a try.  

If the NIC card does not work, and the externals are OK, I don't see what else I can do.
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James Murphy
Phil Davidson

Some motherboards have utilities that you can run on them.  Dell's hardware has such programs that test them without booting to an OS.  This can tell you if the motherboard is defective.
Mike Caldwell

ASKER
Finally got ETH1 configured and ETH0 disabled.  Now reaching the internet.  Thanks to all.
Mike Caldwell

ASKER
Thanks Phil.  Didn't use all of this; the ifconfig got me going down the right path, plus I found the manual on line.
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