A network connects two or more computers to share resources, exchange files, and allow communication. There are three main types of private networks - local area networks (LANs), wide area networks (WANs), and metropolitan area networks (MANs). LANs connect computers within a small geographic area like a single building using technologies like Ethernet. WANs connect multiple LANs over greater distances with varying speeds depending on connection costs. MANs connect nearby LANs within a few dozen kilometers at high speeds, allowing nodes to communicate as if on the same LAN. The definitions between LANs, WANs and MANs can sometimes overlap depending on specific network configurations.