Network segmentation: what it is and how to implement it

What is network segmentation, exactly?

Network segmentation is the practice of dividing a computer network into smaller subnetworks (also called “segments,” hence the term “segmented network”), each of which can function as a separate unit.

By following this architectural approach, you can define how traffic will flow between different parts of the network. This can be achieved by establishing specific security controls and policies for each segment.

The purpose of all this is to improve network performance, simplify management, and contain potential threats within a specific part of the network, preventing them from spreading to other areas.

How does network segmentation work?

Dividing a network into smaller, manageable parts is no simple task, especially when the network itself is quite expansive—it takes careful planning, IT know-how, and the right resources. The idea is to have elements like the client database, email servers, company website, guest Wi-Fi, and internal applications as independent parts of the network.

Enterprise network segmentation starts with figuring out how to divide the network based on criteria like function, security needs, or business requirements. After that, you use a mix of hardware (routers, switches, and firewalls) and software (virtual LANs, cloud technologies) to break the network into segments and control how traffic flows between them.

Once you’ve got the segments set up, the next step is to monitor and manage each of them, which can be made easier with tools like security information and event management (SIEM) solutions.

Network segmentation and zero trust

Network segmentation is key to how companies manage access to their digital resources. Back in the day, companies used to follow the “assumed trust” principle—the idea that everyone in the company was a good guy, and therefore, could be trusted with access to all company data and services.

However, after thousands of human errors and security breaches caused by bad actors, companies have shifted to the zero-trust model. This approach assumes that no one should automatically have full access to the company’s network and virtual assets. Instead, they must be verified and granted access only to the resources they actually need.

To make this a reality, companies use a few different strategies, with network segmentation being one of them. How so? Zero-trust network segmentation refers to IT teams creating dedicated subnetworks for specific groups of users, ensuring they cannot move beyond their designated limits. This adds an extra layer of defense and aligns with the “never trust, always verify” motto of zero trust. Each subnetwork functions as a secure zone, with access protected by authorization protocols.

And if you combine all of this with identity and access management (IAM) solutions to securely manage user credentials, and network access control (NAC) tools that restrict access based on user or device authentication, you've got yourself a solid system for keeping the network running smoothly while minimizing risk.

The benefits of network segmentation

At this point, you’ve probably got a good idea of the advantages that come with dividing your company network into smaller segments. However, if you're not sure you’ve caught all of them, here’s a rundown of the best examples of network segmentation benefits for you:

Enhanced cybersecurity

Network segmentation helps prevent cyberattacks from spreading across the entire company network. For example, if malware infiltrates a subnetwork, it cannot easily spread to other parts of the network, thereby reducing the potential damage and facilitating a quicker response. Similarly, if someone makes an error and accidentally puts systems at risk, the problem remains confined to the parts of the network they had access to. This makes it much easier to identify the issue and resolve it.

Improved compliance

Complying with policies and regulations like HIPAA and GDPR can feel like a lot of work, but network segmentation can make things easier. By breaking up the network into smaller, more secure sections, businesses can isolate sensitive data in specific virtual environments—only accessible to the right people. Plus, by controlling how data moves between these subnetworks, it becomes a lot easier to demonstrate that you're meeting compliance requirements during audits.

Increased performance

By dividing the network into smaller segments, a company can avoid network congestion, which occurs when a network carries more data than it can handle. This can lead to slow internet speeds, buffering during streams, video call glitches, and difficulty accessing company resources when needed—ultimately affecting employee performance. Keeping network congestion low helps ensure smoother online operations and prevents downtime.

Facilitated incident response

When dealing with smaller segments of the network, it becomes much easier to spot where an incident is happening. From there, that specific area can be isolated to keep the issue from spreading. Since the rest of the network stays secure and there’s a smaller scope to investigate, IT security teams can focus on the affected area and get to the root of the problem much faster.

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How to implement network segmentation in your organization

Before you start breaking your company network into smaller segments, it’s a good idea to get familiar with some network segmentation best practices. That way, you’ll head into the project with confidence and a solid game plan—setting yourself up for a smoother process and better results. Here are a few key things to keep in mind.

Don’t oversegment or undersegment your network

As you read this article, you might get the impression that the more you segment your network, the better. But that’s not quite true. If you go too far, your employees will end up dealing with too many access points, leading to user fatigue, slower workflows, and traffic bottlenecks.

On the other hand, if you don’t segment enough—say, only into 3 or 4 subnetworks—you won’t get the security benefits we talked about. This means your attack surface will still be pretty wide. So, the key here is finding the right balance. Effective network segmentation is about finding that sweet spot in how many parts your company network really needs.

Follow the zero–trust principle

Like we mentioned earlier, keeping your network segmentation secure means sticking to a strict zero-trust policy. In simple terms, no one gets an easy pass—regardless of their role or how long they’ve been with the company. Everyone needs to go through proper authentication before accessing any resources. It may sound tough, but it’s one of the best ways to protect your network segmentation operations and stay in control of who can access what.

Minimize third-party entry points

Chances are, your organization relies on at least a few third-party tools and services to keep things running smoothly. Since these platforms are part of your IT ecosystem, they can also become entry points for cybercriminals if compromised. That’s why it’s important to keep their access limited. Don’t give third-party solutions more reach than they really need. A good way to do this is by setting up dedicated access points that connect them only to specific segments of your network. That way, even if something goes wrong on their end, the issue will not spread easily into your company network.

Protect all endpoints

As an employer, you’re providing your team with devices, business accounts, and access to company data. With that comes the responsibility of making sure what you provide can’t be used against your company, and that each employee’s device and account are properly protected.

That includes giving employees access to the right subnetworks—but it doesn’t stop there. You also need to use antivirus software and monitoring tools to ensure only authorized devices get through—so that, much like in Homer’s Iliad, you’re not inviting in modern-day Trojan horses, which could bring chaos once inside.

Monitor all your subnetworks

Segmenting your network is just the beginning—the real work begins after that. You’ve got to manage and monitor all those subnetworks carefully, making sure you have a big-picture view of the whole network while also keeping an eye on how each part is doing individually. For that, it’s a good idea to use modern monitoring tools to spot any unusual user behavior or get alerted if there’s a data breach, so you can quickly figure out which part of the network needs to be shut off.

How NordPass can help

While it is not software dedicated strictly to network segmentation, NordPass is a tool that can help your organization control access to company resources and secure multiple endpoints to minimize the risk of a cyberattack.

NordPass is more than just an encrypted password manager that allows teams to securely store, manage, and share business credentials, credit card details, and sensitive information—it is also a cybersecurity solution for managing user access to company resources and monitoring data breaches to determine if they involve company data. If you run a large enterprise, you can use NordPass to see what was shared, with whom, and for what purpose, and revoke access with ease when necessary.

The best part is that you can try NordPass before making any commitments—just use the free 14-day trial to see how it can improve your company’s cybersecurity and performance. It would be a shame not to use this opportunity.