This is the first of (hopefully) a serious of learnings, observations, troubleshooting steps, and informative stories learned at my new IT job.  While the job is generally “all IT related”, most of it is network-related due to the interconnectedness of everything among my employer’s systems. So, most of these posts will probably be somewhat network-related. Also, this will hopefully be used to for my CompTIA Continuing Ed credits if I end up not getting Security+ for that.

In this first post, I want to discuss the various pieces of networking hardware and their purposes. All of these are items I work with regularly at work, but they can also be encountered in a home setup.

Routers

                Routers handle…routing. That is, when a piece of information needs to travel on the network (aka a “packet”), the routers handle moving that packet FROM one network TO another (this differentiates them from Switches, below). In a later post I’ll discuss how the equipment knows what to do, but in the meantime just think of a router as a device that helps packets move outside their home network and find where they should go next.

                Many devices include a routing function – firewalls, dedicated routers, and so on. In a home setting, your ISP-provided equipment includes a router so that packets can get outside your home to the rest of the internet.

Switches

                A switch is, basically, a way to plug multiple network connections into a single device, which is then itself plugged in via a single cable somewhere else. A common setup might be that each PC/smart TV/etc. on a single floor of a building is plugged into a single switch for that floor (or, in a smaller building, a switch for the entire building). Then, the switch has a single cable run from it to another destination (a “master” switch, or a router/firewall). This removes the requirement to have EVERY cable from EVERY device plugged into your firewall/router.

Firewalls

                I’ve mentioned firewalls several times. These are a security device that handles packet/traffic flow according to pre-determined rules setup inside it. I think of a firewall as “a device that routes packets from one port to another based on the rules you set”. In my settings, the firewall sits between the switch(es), which are plugged into its “LAN” ports, and the ISP equipment, which is plugged into the firewall’s “WAN” port(s). Inside the software of the firewall, we determine what traffic can flow where (LAN to WAN and vice-versa) according to business needs.

                More advanced firewalls can also have routing functions, switching functions, DHCP/DNS functions, and more.

Access Points (APs)

                In our settings, APs are wireless APs. Via an ethernet cable run from the firewall/switch to the AP, the AP then broadcasts a WiFi signal for wireless devices to connect to. Based on the setup, they either expand an existing WiFi network, OR serve an independent wifi signal that’s routed back via the ethernet cable to the main network.

VPN

                Virtual Private Networks (VPNs) are a (usually) software-defined network that runs on computer. In  our setting, it’s an app that, after logging into it, connects via an encrypted tunnel to a firewall somewhere else. All traffic is 1) routed through the tunnel. This mean it can’t be snooped on our monitored in-transit, for security purposes. Additionally, since it “comes out” on the other end of the tunnel at the business firewall, 2) the computer can function as if it were physically plugged into the network at the business. This means that a laptop can connect to local resources at the office, but, when taken home, the VPN can be connected so the laptop can STILL connect to “local” (at the office) resources WITHOUT sacrificing security or having to allow those resources to have an open, inbound connection.

Summary

A common “connection” flow might be something like this:

INTERNET -> ISP Equipment -> Firewall/Router -> Switch(es) — many connections to different devices and access points. Additionally, a VPN (in our setting) logs into the Firewall and would be branches off of that.

That concludes a brief survey of networking equipment and applications. Next week, we’ll look at various Ports & Protocols that network traffic uses, and how that can be used on a firewall for increased security.