Everything in my "operating system" is 16-bit x86 code. It uses regular DOS packet drivers. I have also started writing my own DOS kernel, but it is not ready yet. The server uses FreeDOS kernel. That's why I write the "operating system" in quotation marks.

And because my TCP/IP stack is 16-bit code, it probably won't work for your system. It's just a DOS program that has an interrupt service routine that the other programs can call.