It had a variant "Windows 3.11 for Workgroups" (1993-11), which was the second Microsoft OS with built-in networking, after "Windows 3.1 for Workgroups" (1992-10).
I have actually used "Windows 3.11 for Workgroups" with some coaxial-cable Ethernet NE2000 cards, but I do not remember what network protocols were used.
With all earlier MS-DOS or Windows versions third party networking solutions had to be used.
My first job was at a bank that used Windows 3.11 on all the corporate desktops (late 90s). We had 10mbit ethernet IIRC.
Periodically someone somewhere would plug both ends of an ethernet cable into the wall sockets, causing a broadcast storm and every PC in the building would freeze - Not even the mouse pointer would move.
I have actually used "Windows 3.11 for Workgroups" with some coaxial-cable Ethernet NE2000 cards, but I do not remember what network protocols were used.
With all earlier MS-DOS or Windows versions third party networking solutions had to be used.