CMD which help to narrow it down to missing driver
sudo lshw -class network
Which had:
*-network UNCLAIMED
I compared my HW ID 8086:15fa here and according to this https://cateee.net/lkddb/web-lkddb/E1000E.html included in Kernel 5.5–5.11, 5.12-rc+HEAD (so my 5.4 is just one version to old)
here few cmd to check
lspci -knn
sudo lshw -class network
sudo lspci -v
dmesg | grep "00:1f.6" #based on previous output
dmesg | grep "8086:15fa" #based on previous output
example output
tilo@trex-lx:~$ sudo lspci -v
00:1f.6 Ethernet controller: Intel Corporation Ethernet Connection (14) I219-V (rev 11)
Subsystem: ASRock Incorporation Ethernet Connection (14) I219-V
Flags: fast devsel, IRQ 255
Memory at a3400000 (32-bit, non-prefetchable) [disabled] [size=128K]
Capabilities: [c8] Power Management version 3
Capabilities: [d0] MSI: Enable- Count=1/1 Maskable- 64bit+
tilo@trex-lx:~$ dmesg | grep "00:1f.6"
[ 0.350866] pci 0000:00:1f.6: [8086:15fa] type 00 class 0x020000
[ 0.350928] pci 0000:00:1f.6: reg 0x10: [mem 0xa3400000-0xa341ffff]
[ 0.351165] pci 0000:00:1f.6: PME# supported from D0 D3hot D3cold
tilo@trex-lx:~$ lspci -knn
00:1f.6 Ethernet controller [0200]: Intel Corporation Ethernet Connection (14) I219-V [8086:15fa] (rev 11)
Subsystem: ASRock Incorporation Ethernet Connection (14) I219-V [1849:15fa]
tilo@trex-lx:~$ sudo lshw -class network -short
H/W path Device Class Description
=============================================================
/0/100/1d/0 wlp3s0 network Dual Band Wireless-AC 3168NGW [Stone Peak]
/0/100/1f.6 network Ethernet Connection (14) I219-V
tilo@trex-lx:~$ sudo lshw -class network
*-network
description: Wireless interface
---removed---
*-network UNCLAIMED
description: Ethernet controller
product: Ethernet Connection (14) I219-V
vendor: Intel Corporation
physical id: 1f.6
bus info: pci@0000:00:1f.6
version: 11
width: 32 bits
clock: 33MHz
capabilities: pm msi cap_list
configuration: latency=0
resources: memory:a3400000-a341ffff
tilo@trex-lx:~/Downloads/Preboot_26.1/APPS/BootUtil/Linux_x64$ sudo ./bootutil64e
Connection to QV driver failed - please reinstall it!
Intel(R) Ethernet Flash Firmware Utility
BootUtil version 1.7.27.1
Copyright (C) 2003-2020 Intel Corporation
Type BootUtil -? for help
Port Network Address Location Series WOL Flash Firmware Version
==== =============== ======== ======= === ============================= =======
1 A--removed-D 0:31.6 Gigabit N/A FLASH Not Present
Intel driver download:
https://www.intel.com/content/www/us/en/support/articles/000005480/ethernet-products.html
https://downloadcenter.intel.com/download/15817
Install see here: https://askubuntu.com/a/1094806/37213
## unpack
tar xfv e1000e-3.8.4.tar.gz
##change dir
cd e1000e-3.8.4/src/
## install
sudo make install
## reboot
Note: needs to be repeated after kernel update.
Also Ubuntu LTS and Linux mint support to use newer kernel (via HWE stack) to avoid the manual install of the driver.