"fire wall"
originally meant, and still means, a fireproof wall intended to prevent the spread of fire from one room or area of a building to another.
How does the internet work
The first thing your browser has to do is to establish a network connection to the machine where the document lives. To do that, it first has to find the network location of the host www.tldp.org (‘host’ is short for ‘host machine’ or ‘network host'; www.tldp.org is a typical hostname). The corresponding location is actually a number called an IP address (we'll explain the ‘IP’ part of this term later).
Home network
you need a modem a wireless or wire rador and connection for eahc of your computers