TABLE OF CONTENTS In this chapter, we look at what a Network+ technician needs to know about network infrastructure. In Chapter 3, we discussed network devices such as routers, switches, hubs, and bridges. Here we ll expand on the technologies that we covered in Chapter 3 and take a look at some more advanced network components, including firewalls, proxy servers, and demilitarized zones (DMZs).
Figure 9.1 presents an illustration of the various network infrastructure concepts that you ll learn about in preparation for the Network+ exam. A firewall sits at the edge of your corporate network, making decisions about what kinds of traffic should (and should not) be allowed to reach your internal hosts. A proxy server acts as a go-between to retrieve Web pages and other Internet resources for your internal clients as well as to cache Web content locally so that your clients can access it faster. Within the internal network, you can control network traffic through the use of virtual LANs (VLANs), which are implemented using network switches. Your internal users can access company information and share resources using an intranet, which is typically hosted on a Web server located in your company s internal network. To provide access to internal resources for external users such as vendors, business partners, and customers, you can deploy an extranet using Web browsers on the client end and secure tunnels such as virtual...
