Before the Internet sent its first TCP/IP packet 1/1/1983, the original WAN was the ARPANET. Run by the military, it connected researchers at military bases and a select few universities with military sponsorships.
Connections were dedicated 56K phone lines.
The net could not grow beyond 256 hosts. 8 bit addresses allowed 64 nodes (locations) and 4 hosts (servers) per node.
Clients were dumb terminals connected directly to hosts with serial cables or dialup modems.
This ARPANET Map is from 1972.