To ensure you have the safest and most compatible version, you should download the utility directly from the official Realtek website .

The Realtek Ethernet Diagnostic Utility is a critical tool for identifying and resolving connectivity issues on PCs using Realtek network adapters. Whether you're facing slow internet speeds, intermittent disconnects, or a complete lack of connection, this utility provides a deeper level of insight than standard Windows tools. Where to Download the Utility for Windows 10