Network Security Scope

Let’s examine what a typical IT infrastructure looks like. The seven domains of a typical IT infrastructure, depicted in FIGURE 14-5, are common for small office/home office (SOHO), small and medium-sized business (SMB), and enterprise organizations. It doesn’t matter how small or large, IT infrastructures all have these common elements. Here is a quick definition of each of the domains:

An illustration. The domains are as follows: User domain, Workstation domain, LAN domain, LAN-to-WAN domain, Remote access domain, WAN domain, and System or application domain. The user domain covers the users with access to the other six domains. A computer where the activity takes place is identified as the workstation domain. LAN domain consists of the server and hub; the workstation domain is connected to the LAN domain. LAN-to-WAN domain consists of a filtering firewall and a router, to which the LAN domain is connected. This domain is connected to the WAN domain that consists of the internet and spans over a large geographical area. The WAN domain is connected to the System or application domain; this domain is made up of firewall, mainframe, and application and web servers. Remote access domain functions through a broadband internet to which a remote user is connected. This domain is connected to the LAN-to-WAN domain.

FIGURE 14-5 Seven domains of a typical IT infrastructure.

  • User—Includes humans, which are the weakest link in the entire security chain.
  • Workstation—The point of entry for the user into the network and IT infrastructure.
  • LAN—The ...

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