Microsoft quietly added a built-in network packet sniffer to the Windows 10 October 2018 Update. Pktmon is a program that monitors the network activity flowing over a computer down to an individual packet level. It can be used by network administrators to diagnose networking issues, see what types of programs are being used on a network, or even listen in on network conversations sent via clear text. The program has no mention on Microsoft’s site that we could find, and we had to learn how to use it by playing with the program.
Source: https://www.bleepingcomputer.com/news/microsoft/windows-10-quietly-got-a-built-in-network-sniffer-how-to-use/