If you have a USB fast Ethernet from Realtek then you might want to check the drivers below. There are a number of options such as Windows 10 up to and including Windows XP. There are the latest drivers for the products which have been listed below.
Realtek USB 2.0 Fast Ethernet products:
The following products will work with this driver so check your USB Fast Ethernet from Realtek and see if it has the following chipsets in it from Realtek. Note also that this is a USB 2 driver and a bit of an older technology.
The following operating systems are supported by this driver so download the appropriate driver for your hardware and operating system. The files are large but should not take less than 3 minutes to download on a DSL connection.