Network segmentation is the process of dividing a network into smaller parts for various reasons—control, security, and boosting performance. It is also referred to as “network segregation,” “network partitioning,” and “network isolation.” Each part of a segmented network is called a “subnetwork” or “subnet.”

So when you’re asked “What is network segmentation?,” think of a subnet as a room in your house. You divide your living area into different spaces to designate areas for rest, recreation, and work. Without the partitions, you may end up eating anywhere, thus inviting pests if you don’t have that much time to clean daily.

Other interesting terms…

Read More about Network Segmentation

Network segmentation, like any architectural approach, has various use cases and benefits. But first, you may want to watch this video for a better idea of how it works:

What Are the Uses of Network Segmentation?

Organizations can segment their networks to do the following tasks.

Create a Wireless Guest Network

A guest network limits the risk of confidential corporate information falling into the hands of malicious guests or even contractors. Network segmentation lets a company offer a Wi-Fi service that provides Internet but not network access to visitors and contractors. As such, anyone who logs in to its network with guest credentials gets Internet connection but not access to the organization’s files or communication system.

Limit User Access

Insider threats are real. They can take the form of unhappy employees or spies. One way companies protect their secrets from insiders is by giving each department its own subnet. Within that subnet, group members have different access levels. Only those in the highest positions typically get administrator privileges. And any time an unauthorized user tries to access files he or she isn’t allowed to, an alert is triggered, and an investigation ensues.

Enforce Public Cloud Security

While cloud service providers are typically responsible for securing a customer’s cloud infrastructure, the client needs to protect its operating systems (OSs), platforms, access, data, intellectual property, source code, and content on the infrastructure. Network segmentation can play an essential part in isolating applications in cloud environments.

Ensure Regulatory Compliance

Some organizations, depending on their industry, are required to adhere to strict regulations, including the Payment Card Industry Data Security Standard (PCI-DSS) for those that keep customers’ credit card numbers. Network segmentation can isolate all credit card information within a strict security zone and create rules letting only authorized users access the area.

What Are the Benefits of Network Segmentation?

While network segmentation may come with certain costs, experts say its benefits outweigh the challenges. Some of these are identified below.

Slow Down Attackers

No organization is immune to attacks, cyber or otherwise. A total of 1,001 data breaches exposing almost 165 million records in the U.S. alone were recorded in 2020. But network segmentation can buy companies extra time during an attack. Attackers that successfully breach a segmented target network will need additional time to break out of a segmented portion to get to what they really want.

Reduce Damage from a Successful Attack

Since robust network segmentation can keep attackers from breaking out of a subnet before an organization contains the breach, their access is also cut. As such, the damage caused by the breach is limited.

Improve Data Security

Network segmentation makes it easier for organizations to protect their most sensitive data. They can limit access to confidential information to a handful of people. Should data loss occur, identifying the cause would be easier, too.

Make Least-Privilege Policy Implementation Possible 

Companies that rely on restricting user access for protection typically have robust network segmentation. So even if a user’s access credentials get compromised or abused, it’s easier to track down who the responsible party is—insider or outsider.

What Are Some Network Segmentation Best Practices?

To implement network segmentation effectively, companies can keep these must-dos in mind.

Identify All Network Users and Which Data They Need Access To

There’s no way you can segment your network properly if you don’t know who needs access to what. To keep data breaches at bay, you should limit each user’s access to only the files and systems they need to perform their jobs. User and role identification must be done before network segmentation so you don’t have to repeat the process later on, costing additional time and money.

Create Separate Access Portals for Outsiders

More than half of the organizations that SecureLink and the Ponemon Institute surveyed in 2020 suffered from a breach due to a third party. That makes creating a more secure access portal specifically for third parties on your corporate network a must. Make sure this portal won’t allow them to copy or exfiltrate data from your company.

Avoid Undersegmentation and Oversegmentation

Note that network segmentation can be tricky. If you divide your network into too many segments, placing employees in the right partition can become complicated. Having too few segments, meanwhile, can weaken your security.

Make Regular Network Auditing Mandatory

Sadly, the only way to truly protect your network from any kind of attack is to constantly monitor it for holes or bugs. Ensure that no attackers (insiders and outsiders alike) can slip from one subnet to another that can ultimately give them a means to exfiltrate confidential data.

How Does Network Segmentation Differ from Microsegmentation?

Microsegmentation divides a data center into distinct security segments down to the individual workload level. It is, therefore, more granular than network segmentation. Still a bit confused? Let’s look at an example.

In network segmentation, the same data and systems can be accessed by all the members of the marketing department, for instance. Let’s call that the marketing subnet. To increase security, you can apply microsegmentation to the marketing subnet. In the process, you can then limit data and system access based on a user’s role in the department. The director can have access to all data and systems and managers can access more data and systems than rank-and-file employees (writers, editors, graphic artists, etc.). For even tighter security, access levels can be assigned individually.


As you’ve seen, the answer to the question “What is network segmentation?” is quite simple. It’s a means to manage, protect, and boost the effectiveness of groups of systems within a network.

Key Takeaways