“byte-space” is a terminal-based internet simulator set in the early internet era. Features include:
building networks
browsing text-based websites
sending email
seeing packets travel between machines in real-time
a custom hand-rolled filesystem with inodes, permissions, and directories
a virtual kernel that implements real Unix-like syscalls (open, read, socket) and a full TCP/IP stack; programs interact with it exactly like they would a real OS
It is a pretty cool project and you should definitely star it on Github.