Firewalls

56 3.5 Summary

3.5 Summary

As explained in earlier chapters, a firewall on a computer network is

a device that protects a private local network from the rest of the

world (public parts of the same network or the Internet at large). The

role of a firewall is typically filled by a computer (or computers) that

can reach both the private network and the Internet, thereby allowing

it to restrict the flow of data between the two. The protected network,

therefore, cannot reach the Internet, and the Internet cannot reach

the protected network unless the firewall computer allows it. For

someone to reach the Internet from inside the protected network,

they must ...