A host is any device attached to the network that uses TCP/IP. To receive and deliver packets successfully between hosts, TCP/IP relies on three values, that the user provides: IP address, subnet mask, and default gateway.
The network administrator provides each of these values for configuring TCP/IP on a computer. Windows NT users on networks with DHCP servers can take advantage of automatic system configuration and do not need to manually configure TCP/IP parameters. This section provides details about IP addresses, subnet masks, and IP gateways.