260 CHAPTER 7 Network devices are pretty important as using the wrong tool can potentially harm the devices that you are attempting to test. 7.2 APPROACH Routers and switches perform the most fundamental actions on a network. They route and direct packets on the network and enable communications at the lowest layers. Therefore, no penetration test would be complete without including network devices. If the penetration tester can gain control over these critical devices, he can likely gain control over the entire network. The ability to modify a router's configuration can enable packet redirection, among other things, which may allow a penetration tester the ability to intercept all packets and perform packet sniffing and manipulation. Gaining control over network switches can also give the penetration tester a great level of control on the network. Gaining even the most basic levels of access, even unprivileged access, can often lead to the full compromise of a network, as we'll see demonstrated in the Case study: the tools in action section of this chapter.