Local Area Network or (LAN), examples are, home networks, office workspaces, schools, etc. are closed networks, which is also referred to as an intranet. Multiple devices are connected and communicates with each other within said closed environment.   

Wide Area Network or (WAN) is a large network of information that supports multiple LANs connecting to the internet.

Let’s discuss how does an IP, Switch, Subnet, Router & Gateway, Firewall, NAT, DMZ and Port Forwarding all work together?

Internet Protocol or (IP), is a logical address to locate or identify your specific device, for example, if your logical local IP address is 192.168.10.20 and you want to print something from your computer, your computer would search your local network for a printer that’s within that IP address and send a print request message.

The purpose of a Switch is to grant route permission to data within various types of communication networks. Similar to how traffic lights regulating roadway movement.

A Router is a network device that forwards data packets between different computer networks, {think in terms of a security office, sitting at a check point and inspects all items going in and out of a building}. In simple terms, a router provides network security.

In computer networking, a Gateway is a router’s IP address that traffic flows through when it's bound for a destination outside the LAN. When there’s a single router and other connected devices, the router's private IP address is the default gateway or (Gateway).

Later on, I will dive deeper into the many roles of a router and the different rules and functions of each subsection.

Now you may ask; How does a machine knows whether another machine is sitting within a main local area network, or sits in an outside network?

A Subnet or Subnetwork Mask is short for ‘Subordinate Network’ or ‘Subordinate Network Mask’ sits within the local area network to mask actual IP address, it does this by mimicking the real IP address, but I assure you, it’s not an IP address. Let me explain…

Let’s say that your computer’s IP address is 192.168.0.101 and your printer’s IP address is 192.168.0.11 – between both IP address, sits the Subnet, which could be 255.255.0.0 and within that subnet, the first two octets (255.255) indicates that this LAN has a fixed range of (192.168) and any devices within that range, would potentially be in said network, and the octets (.0.0) denotes the free range, meaning that there can be any device within that range, for example: An IP address could be 192.186.0.200, because the last two octets have a range of (.0.0)

That being said, a Subnet defines and determines your local area network range.

Network Address Translation or (NAT), as the name suggest, it allows the router to translate its IP address into a different IP address to communicate with the wide area network - the Internet.

Firewalls protect local area network from being accessed by outside computer or other devices that’s trying to connect with any devices in the LAN; that’s a major security risk. The firewall commands a set of passive rules which are defined to enable a precise standard for protecting the local network from unauthorized access. The firewall blocks all ad-hoc requests traversing from a WAN, those outside devices /s will first have to sends its requests through the DMZ.

A Demilitarized Zone or (DMZ) is another security feature of a Router, whereby an outside device attempting to communicate with a device inside a LAN, must first request access from the devices sitting inside a demilitarized zone.   

Port Forwarding is a ‘configuration’ done to a selected port of a network switch, which allows communication for specific applications and/or device/s to perform a defined task. For instance, a Web server’s default port is: 80, a Tomcat default port is: 8080, and Cisco Meraki default port is: 443. 

In closing, every computer network needs some type of the above-mentioned applications, to perform their required tasks.