On Sun, 2020-02-09 at 14:12 +0000, Patrick O'Callaghan wrote:
On Sun, 2020-02-09 at 23:39 +1030, Tim via users wrote:
> On Sun, 2020-02-09 at 08:05 -0400, George N. White III wrote:
> > Check components near the ethernet port for signs of damage.
>
> Though there's every chance that there won't be any visible signs.
> Fried electronic parts don't have to be charred.
>
> I have to periodically replace ethernet switches, and/or network cards
> on computers that are connected between buildings. There can be a
> significant voltage difference on the mains wiring between buildings,
> and even between circuits within a building.
>
> It seems that few ethernet interfaces bother to use galvanic isolating
> transformers, or opto-coupling, so they're vulnerable to voltages on
> earthing.
>
> Static shock is also a posibility (the inevitable walking across the
> carpet and zapping things, or people wearing static electricity
> generating clothing).
>
> Our recent computers have motherboard ethernet ports, I don't fancy the
> chances that the ethernet port being zapped will be limited to just the
> ethernet port components. The previous dead network cards didn't just
> not network, they would hang the PC, prevent booting, and cause random
> crashes.
Yes, I'm fairly sceptical as to this being the explanation. This is a
home desktop with onboard Ethernet and the router is on the same mains
circuit in the same room. The mobo is showing no other issues though
it's about 6 years old so I'm planning on getting a new one this year
anyway, mostly because it has no NVMe slots and can only support 16GB
of RAM.
If the problem persists with the new NIC I'll know to look elsewhere.
Phase of the moon, maybe.
OK, installed the new NIC and no errors so far, touch wood. I also
didn't notice any obvious damage to the mobo.
However, it's still running at 100Mbs:
$ sudo ethtool enp4s0
Settings for enp4s0:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Supported pause frame use: Symmetric Receive-only
Supports auto-negotiation: Yes <--------------------*
Supported FEC modes: Not reported
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Advertised pause frame use: Symmetric Receive-only
Advertised auto-negotiation: No <--------------------*
Advertised FEC modes: Not reported
Speed: 100Mb/s <--------------------*
Duplex: Full
Port: MII
PHYAD: 0
Transceiver: internal
Auto-negotiation: off <--------------------*
Supports Wake-on: pumbg
Wake-on: d
Current message level: 0x00000033 (51)
drv probe ifdown ifup
Link detected: yes
Note that Auto-negotiation is Off (unlike the old NIC, which always had
it On).
I see that /etc/sysconfig/network-scripts/ifcfg-Wired_connection_1 has:
ETHTOOL_OPTS="autoneg off speed 100 duplex full"
So I changed that to turn autoneg on and speed to 1000, and rebooted.
The system came up with no network, so I reverted the change. Clearly
that isn't the right way to do it.
Recommendations are welcome.
poc