Most folk just go to powerline networking.
Looking for recommendations - How can i get cable internet to every coaxial port in my house? The modem is currently wired into a coaxial port downstairs. I have 2 coaxial ports and a phone jack upstairs, and one coaxial port and one phone jack downstairs. I have what appears to be a central panel in the entryway closet, as well as an outdoor box which I assume is for hooking up satellite tv.