Typical server program

text-file

1. Create a socket:
    server_fd = socket(...);
2. Bind to a well known IP address and port#:
    ret = bind(server_fd, ...);
3. Mark the socket as passive by changing it's state to LISTEN:
    ret = listen(server_fd, ...);
4. Wait for a client to connect, and get a reference file descriptor:
    client_fd = accept(server_fd, ...);