a router is a network device that connects two networks together.

    the router connects your local area network (lan), or the group of pcs in your home or office, to the internet. the router processes and regulates the data that travels between these two networks.

    the router’s stateful packet inspection (spi) firewall and network address translation (nat) technology protects your network of pcs so users on the internet cannot “see” your pcs. this is how your lan remains private. the router protects your network by inspecting the first packet coming in through the internet port before delivery to the final destination on one of the ethernet ports. the router inspects internet port services like the web server, ftp server, or other internet applications, and, if allowed, it will forward the packet to the appropriate pc on the lan side.

    nat (network address translation):

    nat technology translates ip addresses of a local area network to a different ip address for the internet.

    lan (local area network): the computers and networking products that make up the network in your home or office.