Legacy systems require manual installation.
# Check if detected
lsusb | grep Realtek
The JP108 is a USB 2.0 to 10/100 Mbps Fast Ethernet adapter.
It lacks a true manufacturer; instead, multiple Chinese factories produce it using reference designs from ASIX Electronics (typically the AX88772A chipset) or, less commonly, the SR9900 (a clone of the AX88772). Jp108 Usb Lan Driver
Fix:
System Settings → Energy Saver → Uncheck “Put hard disks to sleep when possible”. Or use a powered USB hub. Legacy systems require manual installation
sudo apt update
sudo apt install r8152-dkms
sudo modprobe r8152 Fix: System Settings → Energy Saver → Uncheck