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