GNU/Linux Ubuntu 20.04 Realtek RTL8125 Ethernet Driver Setup Guide
How to Install Realtek R8125 Ethernet PCI Controllers Driver on Ubuntu 20.04 Focal GNU/Linux – Step by step Tutorial.
Realtek R8125 is a Gigabit Ethernet PCI controller chip commonly used in network interface cards (NICs) for desktops, laptops, and other computing devices.
Especially relevant, as Alternative you may also see: R8125 Package Setup Guide.
The Supported RTL8125 Controllers are:
- RTL8125
- RTL8125B(S)

GNU/Linux Ubuntu Rtl8125 Ethernet PCI Controller Driver Installation Guide