What is Network Segmentation? Definitions and examples

The occurrences of cybersecurity and ransomware attacks continues to increase every year. But the fact that they occur more often, doesn’t mean that you or your clients have to fall victim to them.

In fact, there’s a relatively easy way to rapidly increase your security against these attacks, and it’s called “network segmentation”.

In this article we’ll cover what network segmentation is, why it’s important, and the various ways it can help you stay protected against unauthorized (virtual) trespassers.

What is network segmentation?

In the simplest terms, network segmentation is literally the division of a computer network into smaller subnetworks in order to prevent data breaches and improve performance and security. Network segmentation can be done both physically with hardware, or not-physically like online or with software.

A network that is not segmented is often referred to as a “flat network”.

By dividing the network into separate contained parts, network segmentation makes it much more challenging for unauthorized users (like hackers for example) to jeopardize or implicate the whole network.

How exactly the network is divided into what segments depends on a few different factors, including the nature of the network and the devices used to interconnect end stations.

How does network segmentation work?

Similar to a traffic light, network segmentation works by governing exactly what traffic, and how that network traffic flows throughout the different segments.

You can choose to prohibit all network traffic in one segment from flowing to another subnetwork entirely, or you can constrict the flow by traffic type, source, destination, or a number of other options.

The outline for how an organization chooses to segment its network is referred to as a segmentation policy.

What is a network segment example?

There are several different ways in which an organization can choose to segment its network. That being said, network segmentation is usually executed via an amalgamation of Virtual Local Area Networks (VLANs), Software Defined Networking (SDN), and firewalls.

Segmentation by VLAN: the most common way that networks are segmented is by VLANs or subnets, even though they can be challenging to maintain. VLANs are used to connect hosts virtually, and subnets use IP addresses to create smaller network segments that are connected to one another by networking devices.

Segmentation by Firewall: given that firewalls are security devices (either hardware or software) that can help protect networks by blocking intruders from getting unwarranted access to them, it’s no surprise that segmentation is often conducted by using different firewalls. Firewalls can be deployed inside a network to create separate internal zones that divide the distinct functional areas from one another.

Segmentation by SDN: Another possible approach to segmentation is by using an SDN-automated network overlay. One challenge with this approach is the level of complexity and intricacy that is necessary for successful micro-segmentation.

Why is network segmentation important?

By segmenting the network into separate but contained parts, it makes it much more difficult for unauthorized users to compromise the entire network as the different parts aren’t connected.

For example, if a malicious attacker gains access to your entire network, they will probably try to move around the network in order to access and later exploit the pirated data they came across. As such, if your network is flat (meaning all systems connect to each other without going through any intermediary device), all a bad actor really has to do to gain access to the entire ecosystem is breach only one access point.

However, when a network is divided into different subnetworks with controlled traffic flow, malicious traffic shouldn’t have instant access to the network as a whole. The hacker will therefore only be able to immediately have access to the first section they breached, giving IT time to protect themselves and halt the intruder from accessing any more data.

What are the benefits of network segmentation?

The benefits of network segmentation are almost as numerous as the different ways you can choose to segment your network. Hint: there’s a lot!

A few of the benefits of network segmentation include but are not limited to:

Improved network monitoring: by dividing a network into methodized sub sections makes it much simpler and more efficient at identifying certain threats, and making those threats become isolated incidents instead of a giant breach.

Providing a guest wifi network stress-free: ever wondered why many times companies or hotels have different wifi networks for guests than for internal employees? By splitting up the wireless networks into several different ones, a company can offer wifi to guests with minimal risk, as guests (and hackers by proxy) can enter only a microsegment of the network and nothing else.

Protect vulnerable devices: network segmentation can block destructive traffic from reaching vulnerable devices that are not equipped with advanced security defenses of their own—a hospital’s connected infusion pumps, or different smart home devices.

Lower costs to large (and not-so-large) enterprises: network segmentation can separate payment systems from those that don’t, or from systems that require specific audit processes from those who don’t, so this way, the expensive compliance requirements need only to apply to the in-scope systems, instead of applying to the entire network.

Improved network security: as explained earlier, network segmentation can significantly improve an organization’s cybersecurity by limiting how deep and to what areas a cyber attack can spread, because it keeps an outbreak confined to a single section.

How do we segment a network?

There are a variety of ways in which an organization can choose to segment its network. Network segmentation can be done both physically with hardware, or not-physically like online or with software.

Most organizations usually execute network segmentation via their own blend of VLANs, Software Defined Networking, and firewalls.

An example of a physical segmentation is by using a physical firewall that can act as the subnet gateway. Physical segmentation is considered easier to achieve and maintain than non-physical segmentation.

Non-physical segmentation can be achieved by using Software Defined Networking (SDN) as well as VLANs.

How does segmentation help to improve a network’s performance?

Segmentation can help improve a network’s performance in a myriad of ways.

Firstly, it can improve a network’s performance because it prevents an overload of traffic on a single network.

It can also improve a network’s performance because it’s easier to keep issues or incidents isolated, with more time to react when—or if—they occur.

Is network segmentation a VLAN?

VLANs are often used in order to effectively segment a network.