Fundamentals of Information Systems Security, 4th Edition

Basic Network Security Defense Tools

Defense against these kinds of risks begins with some basic hardware and software tools, such as firewalls, virtual private networks (VPNs), and network admission control.

Firewalls

A firewall controls the flow of traffic by preventing unauthorized network traffic from entering or leaving a particular segment of a network. You can place a firewall between an internal network and the outside world or within internal subnetworks to control access to particular corporate assets by only authorized users. Firewalls are critical elements of networking security, but they are just that, elements; they will not solve all security problems, but they do add a much-needed deterrent.

FIGURE 5-8 shows the role of a firewall ...