Thanks. Here's the output from lspci -v
00:19.0 Ethernet controller: Intel Corporation Ethernet Connection I217-V
DeviceName: Onboard LAN
Subsystem: Gigabyte Technology Co., Ltd Device e000
Flags: fast devsel, IRQ 20
Memory at f7d00000 (32-bit, non-prefetchable) [size=128K]
Memory at f7d3c000 (32-bit, non-prefetchable) [size=4K]
I/O ports at f080 [size=32]
Capabilities: <access denied>
Kernel modules: e1000e
and from the journal:
$ journalctl --boot | grep "e1000e"
Jun 21 16:41:37
carmepc2.uktm.eu.nec.com kernel: e1000e: Intel(R) PRO/1000 Network Driver
- 3.2.6-k
Jun 21 16:41:37
carmepc2.uktm.eu.nec.com kernel: e1000e: Copyright(c) 1999 - 2015 Intel
Corporation.
Jun 21 16:41:37
carmepc2.uktm.eu.nec.com kernel: e1000e 0000:00:19.0: Interrupt
Throttling Rate (ints/sec) set to dynamic conservative mode
Jun 21 16:41:37
carmepc2.uktm.eu.nec.com kernel: e1000e: probe of 0000:00:19.0 failed
with error -2
And that is most likely the answer. Check if there are any other lines
of interest around those. And look in the BIOS to see if there are any
relevant settings.