Connecting to the internet is a fun yet risky venture, especially when you have no safeguards up to protect your activity. Hackers are everywhere looking for unsecured connections and aim to get your data, devices, money, and anything else that they can get their hands on. Don’t believe me? Data breaches were up by 38% in Q2 of 2021 versus the year prior, which also saw its record level of breaches.

There’s a massive market for your digital assets and if you aren’t taking steps to protect your network and the traffic that’s coming and going, you’re leaving your organization exposed to the harsh elements of the internet. It’s crucial that you protect your organization’s network and one way to do that’s to create a network perimeter.

What Is a Network Perimeter Security Architecture?

When you build security around a sensitive location, you establish a perimeter by putting up fences, security cameras, checkpoints to allow traffic in and out of the location and any other security measures that you feel are necessary like sensors or electrification to the fence.

Perimeter security architecture treats your organizational network with the same mentality. The idea is to build a network that’s enclosed and monitored behind an established perimeter that only authorized users and traffic can access or leave.

How Does Network Perimeter Security Work?

Network perimeter security philosophy is decades old and is predicated on the idea that networks are established and managed locally, which are then connected to the global network of the internet.

To establish this concept better, let’s look at a simple network perimeter diagram:

Network Perimeter
Old network perimeters relied on firewalls with basic “allow or deny” internet protocol (IP) access control lists. They’ve evolved a lot since then.
Source: Made in Canva

This is the basic order of operations for how a network will send and receive traffic to and from the perimeter:

Traffic Out

  1. Packets are sent from computer workstations.
  2. Packets are read by the network switch and sent to the router.
  3. Router reads packet data and determines the destination.
  4. Router sends off packet to the firewall―if the firewall is advanced, it’ll read the packet data to ensure sensitive data isn’t leaving the network perimeter.
  5. Firewall greenlights or halts the traffic from leaving the network perimeter.
  6. Packet leaves the perimeter off through the internet to the destination.

Traffic In

  1. Packet arrives at the firewall at the network perimeter.
  2. Firewall scans the packet to determine the sender and recipient and checks against an access control list―if the firewall is advanced it will read the contents of the packet to determine whether it’s safe, suspicious, or malicious.
  3. Firewall either grants access to the safe packet, flags the packet for further inspection, or blocks the packet altogether.
  4. Safe packet is sent to the router to either be sent on to the network switch and onto the recipient workstation or if it’s suspicious, it’s sent to the demilitarized zone (DMZ), which acts as a buffer between the firewall and in the rest of the network.
  5. Recipient workstation unpacks the data and renders the information to the user.

This is the simple explanation of a network perimeter, but there are far more complex perimeter architectures that use different security measures and detection tools. We’ll dive more into that later.

Why Is Network Perimeter Security Important?

Obviously, your network is a valuable and useful asset for your organization that deals with tons of sensitive data. If monetary motivation isn’t enough, there are countless laws and regulations that put the onus on organizations to protect the sensitive information of their partners, employees, customers, clients, and collaborators, including the Health Insurance Portability and Accountability Act of 1996 (HIPAA), General Data Protection Regulation (GDPR), Children’s Online Privacy Protection Act (COPPA), and California Consumer Privacy Act of 2018 (CCPA), and many others.

Basic network perimeter security is the least your organization should be implementing to protect assets, data, and traffic. Otherwise, your business is running around exposed to the worst that the internet has to offer.

What Are the Components of a Network Perimeter?

As I mentioned earlier, my diagram above shows the basic tenets of a network perimeter and gives a simple picture of what happens when traffic is sent to and from a network. For the sake of clarity, here’s a list of all of the major network components as well as all of the components of the perimeter.

Let’s start with the network.

Network Components

  1. Endpoint: Any end device that’s connected to the network where traffic originates or ends up, such as a computer, smartphone, tablet, or server.
  2. Network switch: A routing device that deals with traffic within a local access network (LAN) but not outside of the immediate network.
  3. Router: A device that sorts, sends, and receives traffic from the network to the internet and vice versa. Acts as the gateway between different networks like the door to a gated community.

Network Perimeter Security Components

  1. Firewall: A firewall acts as a gatekeeper for the network perimeter. It filters inbound and outbound traffic based on a set of criteria.
  2. Intrusion prevention system (IPS): A network security tool that monitors traffic flowing in and out of the perimeter while taking action to prevent malicious activity by blocking and reporting it.
  3. Intrusion detection system (IDS): Similar to the IPS, but only acts to detect and alert administrators of malicious activity within a network.
  4. DMZ: A buffer area made of servers not directly connected to the private LAN. Suspected malicious traffic is routed to the DMZ for the purposes of observation. Honeypots of useless yet seemingly valuable data can be set within DMZs to lure attackers and observe their behavior.
  5. Virtual private network (VPN): Provides a private connection between two endpoints by creating an encrypted tunnel that only the two accessing endpoints can access by use of a decryption key.
Full Network Perimeter
Here you can see the layout of a modern network perimeter including firewalls, VPNs, and IDS/IPS systems all working together to inspect traffic and protect the LAN.
Source: Made in Canva

These components all work together to safely route traffic in and out of a local area network while preventing intruders from sneaking their way in and accessing valuable data and assets.

What Is the Future of Perimeter Security Architecture?

As mentioned, this philosophy of security is decades old and while some of the tools have evolved over the years, the existence of cloud computing has eroded the safeguards provided by network perimeter architecture.

People can store their data anywhere and with the rapid shift to remote work during the COVID-19 pandemic, organizations can’t rely on their work-based LAN structures to protect their data.

Even VPNs aren’t a foolproof solution since workers can choose to try to do work without using their VPN for whatever reason like speed or convenience. Additionally, VPNs don’t even cover the issues created by the massive shadow information technology (IT) problem created by personal devices and cloud-based software as a service (SaaS) applications.

While the cloud has worked wonders for companies and workers to be productive wherever they are, it has undermined the security provided by the network perimeter in the first place. This means that security philosophies have to change.

Secure access service edge (SASE) architecture, a term coined by Gartner, is a perimeter-less way forward for businesses to maintain control over their data, networks, and assets from anywhere using cloud-based services, such as:

  • Secure web gateways (SWG)
  • Zero trust network access (ZTNA)
  • Cloud access security brokers (CASB)
  • Network as a service (NaaS)
  • Software-defined wide area networks (SD-WAN)
  • Data loss prevention (DLP)
  • Endpoint detection and response (EDR)
  • Firewall as a service (FWaaS)

All of these tools combined will create a context-based, smart security architecture meant to detect and prevent malicious actions through zero trust principles, deep packet inspection, context-based activity analysis, and identity management.

Should You Invest in Network Perimeter Security?

This is a good question. If you’re currently running minimal to no security, then any improvements to your perimeter architecture are worth the investment. The truth is, SASE is a very new concept and as of now, no one company offers all of the tools necessary in a single package. This means you’ll have to make a significant investment into multiple cloud security and networking vendors to piece together an architecture. This is an expense that many small-to-medium businesses (SMBs) can’t afford at a moment’s notice.

This means that it’s still worthwhile for now to try to strengthen your network perimeter in all ways possible. Perhaps look into a VPN solution for your business or upgrade your basic firewall to a deep packet inspection variant.

Whatever you choose to do, you can count on Digital.com to give you the most up-to-date information on the latest network security tools. We have all of the guides and software reviews you’ll need to make the right decision the first time.