What Is Network Segmentation?

Image of a person holding and tapping a tablet computer with small images of different services and a network background.
Access services through different segmented network parts!

Network segmentation (network partitioning or network isolation) is the process of dividing a computer network into smaller isolated parts or segments. Each segment has different security policies allowing you to control traffic flow between the segments or even block it completely. This enables you to better protect your systems and data from unauthorized access or attacks. 

In this article, I’ll show you applications for network segmentation and how you can use it to protect your security. Let’s start with 4 common uses

4 Common Network Segmentation Use Cases

When you isolate sensitive data and systems into individual segments, you prevent an attacker’s access to them. That makes network segmentation a critical part of a defense-in-depth approach. If you physically separate devices, you limit the damage attackers have on your system if they ever gain access to a network’s isolated segment. 

You can also separate traffic flows and only risk compromising the least-important segments in your system. This helps you prevent an attacker’s access to sensitive data.

These actions help you achieve the following results:

  • Protect your system against Denial-of-Service (DoS) attacks
  • Prevent viruses from spreading through the network
  • Secure wireless networks
  • Separate public networks from private ones
  • Assign different tasks on different ports to balance server loads

Since these results are vital to protecting your sensitive data, here are 4 example cases where you can implement network segmentation at your firm.

1. Guest Networks

When a company grants server access to visitors, it runs the risk of compromising network data. For this reason, users who aren’t employees or part of the organization receive access through guest credentials. That means guests log in to the internet through a microsegment. The guest wireless network ensures visitors can only access certain websites and domains while logged in. This process protects valuable data and keeps it away from prying eyes.

2. Cross-Logins

What’s the best way to protect your network and make sure you don’t compromise security? You need to segment individual internal zones into separate subnets. You also have to first, control access to them, and second, the traffic flow between them. For example, a person in the finance department won’t have access to the HR network server. You can also set an alert to be activated in case of an unauthorized login attempt on the network.

3. Public Domain Segments

Cloud service providers typically offer security for the company’s IT systems’ infrastructure but not necessarily for all the firm’s network content. Segmentation can effectively isolate applications and their data within public or hybrid environments. In this case, users don’t have direct access without need-based permission from someone with higher-level privileges. That way, you keep unauthorized users away from sensitive content. 

4. Virtual Segments

Are you worried about the safety of your most valuable and sensitive data? Network segmentation can help. In this case, network administrators can create isolated zones to store sensitive data, like credit card information. Segments remain protected within a virtually accessed security layer. That offers great flexibility when ensuring PCI DSS compliance and blocking unwanted traffic. All this happens while automatically granting necessary and restricted access through firewall protocols.

How Can You Implement Network Segmentation?

You can implement network segmentation in many ways, depending on your needs and environment. The most basic method is to divide your network into separate physical LAN segments. You’d agree this isn’t quite practical. One common way to divide your network is to create separate Virtual Local Area Networks (VLANs) with firewall application layers. Another way is to use Network Address Translation (NAT) to create different segments.

You can apply these in different methods, but we’ll look into 2 techniques: perimeter-based segmentation using VLANs and network virtualization. 

1. Perimeter-Based Segmentation Using VLANs

In this section, we’ll get to know what VLAN segmentation is, its limitations, and how you can overcome them. 

What Is VLAN Segmentation?

Network perimeters separate VLAN segments, creating a secure boundary based on trust. In effect, users with different accessibility can’t connect to the same segments. A user able to connect to a particular segment is considered internal to it or trusted. That helps devices with different trust levels, connected to the same switch, stay isolated within different segments.

Screenshot of a flow chart of network segmentation using VLANs
VLANs connect users with different functional requirements to the same network segment.

VLANs’ Limitations

The initial intent for creating VLANs was to improve network performance. VLANs are easy to implement and help keep traffic within relevant network segments. In time, though, they grew in popularity as a security tool. Since this wasn’t within VLANs’ initial scope, they have a major flaw which is their lack of intra-VLAN filtering

That means since all traffic goes through an outside router or switch before any protocol filters it, internal segmentation is minimal. In effect, filtering and segmentation take place at fixed points using network settings without segregation for traffic crossing inter-network boundaries. This is why VLAN segmentation is common in systems where network performance is more important than security.

Firewall Integration

If your system requires more emphasis on security, you should implement extra protection layers, like firewalls. IT professionals most commonly use network firewalls to control data flow across different parts or segments within a company. Firewalls help you keep sensitive data inside its boundaries and isolated from another network segment.

After elaborating on perimeter-based segmentation with VLANs, let’s move to the next technique. 

2. Network Virtualization

This is the second technique you can use to apply network segmentation in your company. Let’s start with what it is and how you use it for segmentation. 

What Is Network Virtualization?

To keep up with today’s operational and security demands, many companies set up multiple networks, each tailored for specific functions. These include business operations, accounting, human resources, engineering workstations, etc. That’s why IT experts implement separate segments within security boundaries.

Network virtualization is the key to efficient security segmentation. It enables you to keep attackers at bay, not just with perimeter-based segmentation but also with distributed and flexible policies down each network segment. You can configure virtualized mixed network segments or trust zones while maintaining your organization’s policies to keep a high protection level at your core networks. Data flows freely within a trust zone, while it’s subject to stronger restrictions when it flows in and out of the trust zone.

Network Virtualization Limitations

The downside to this technique is that you might miss-configure your virtual environment. You might’ve been increasingly implementing network segmentation, but you should consider the degree to which you segment network areas. This impacts your environment’s security and is especially true when the devices’ variety and endpoints’ quantity keep increasing. You may need dozens, if not hundreds, of total internal segments.

You’ll require more segmentation, especially as BYOD, cloud, and mobile devices continue to become more popular. These technologies often blur boundaries between networks. As a result, you’ll have ill-defined network segmentation perimeters.

To achieve better security and reach better performance, you need to carefully plan your network architecture. Read on and check network segmentation best practices that’ll help you hit the mark. 

6 Network Segmentation Best Practices 

You have to carefully study and consider how to implement a well-adjusted segmentation design. To make sure your design is efficient, well-rounded, and secure, you’ll need to accommodate all contingencies. Check out the following 6 practices for some useful guidelines.

1. User Tasks Description

Employees have better performance when they adhere to their job description and work within their domain. To ensure a network segmentation project facilitates and efficiently limits every employee’s access, you need to understand how tasks are distributed within your firm. That way, you can perceive who has access to what

If you don’t get the system architecture right from the beginning, your segmentation project will be much more complicated than it needs to be. Take the time to plan a well-adjusted segmentation design and save yourself the trouble later on. This will help you ensure all employees have clear access to their files and work only within their domain. 

2. Over and Under Segmentation

It’s a good idea to segregate your network when you configure your segmentation plan. Yet, too many segments complicate and threaten system security. At the same time, not enough segments make it difficult for users to navigate the system.  

Too many or not enough segments are common issues when you’re applying network segmentation. These issues can even force you to eventually reconfigure your network. Gartner found more than 70% of people implementing network partitioning over-segmented their networks. This is due to not considering the network users’ needs beforehand. 

That’ll lead you to under or overestimate a department’s resources within your firm’s infrastructure. How can you fix this? Layout each user’s needs and study resources allocation carefully. This will help you reduce the complexity, cost, and inefficiency of your segmentation project.

3. Third-Party Limited Access

Third-parties might require access to your company’s servers which might put your data at risk. In some cases, third-party breaches led to some of the highest-profile attacks. It’s vital to create isolated portals for third-party access. That way, they have limited access through specific entry points and can’t compromise your entire network.

4. Access Points and Secured Paths

Keep your firewall’s architecture in mind when you segment your network. It’s important to plan and set access points to minimize cyberattack risk. Access points could be a weak link in your network if you don’t protect them with a secure firewall. Users should be able to easily navigate your network through secured paths without getting around nodes and security walls. This way you won’t compromise your network’s security. 

5. Network Audit

The only thing worse than a poorly protected network is a poorly maintained one. Cybercriminals can slip in from one sub-segment to another unless you make it hard for them. Regular audits help ensure all your access points are still secured. Engage in risk management and make sure all your doors are closed and locked. This will help you minimize cross-attack risks.

6. Network Visualization

Your company’s system is linked between users, devices, and interconnections. It’s essential to design your network based on your needs. That said, you need to combine similar network resources into individual databases. You also should categorize trust zones based on similar trust levels. To succeed, visualize your network using diagrams, flow charts, tables, etc. These help you save time on manual processes and quickly apply security policies to protect your most sensitive data. 

These best practices will help you perfect your network segmentation to reap all the security benefits. Let’s have a closer look at 4 of these benefits.

4 Network Segmentation Benefits

A well-designed network is very important to keep your system safe, as cybercriminals need to work around it to gain access to your data. This is the first barrier they run into. 

To achieve solid security, you’ll need to isolate segments and consider how data flows between them and more importantly where and when you should restrict flow completely. Encryption keys, for example, set firewalls to isolate segments within your digital space. This ensures traffic isn’t interchanged without proper permission.

Network segmentation has several benefits. Here are 4 ways it helps protect your data. 

1. Reduce Congestion

You’ll improve network performance when you implement segmentation with less network traffic on separate network segments. For example, an engineer’s server won’t lag due to crowdedness with accounting traffic.

2. Improve Security

You can limit and/or filter network traffic to protect networks from malware. That means if an intruder gets access to a segment on your network, their data access will be limited to this single segment.

3. Minimize Network Issues’ Impact

Segmentation also minimizes a localized issue’s impact. You can determine the areas at greater risk to add an extra security layer and reduce cyber weaknesses’ impact.

4. Control User Access

Guest credentials allow network visitors with special permissions to only access authorized network segments. This will protect all your data and make it inaccessible to outsiders. Later, you can grant access to intended users with specific accounts.

Final Thoughts

Networks are the Achilles’ heel for many companies since they are cybercriminals’ targets. One single breach could jeopardize all your data if you don’t take the necessary precautions. Here’s where a well-implemented and secured network becomes a great asset for you. 

The only way you’ll stay ahead of the game is to up your IT game and boost your security plan. Network segmentation provides an effective line of defense against cybercriminals. You should consider a personalized approach based on your company’s structure and needs. It’ll help you protect your system and keep attackers at bay.

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FAQ

What is network segmentation?

Network segmentation is also called network segregation, partitioning, or isolation. It’s a security technique in which you divide a network into smaller logical parts or segments. Network segments are isolated through boundaries using different security protocols.

What can I use network segmentation for?

Through traffic control and constrained access, network segmentation balances server loads and improves network performance. It also helps localize and prevent any technical issue and virus spread through the network. It also separates public and private networks, and most importantly secures networks and prevents DDoS attacks.

What are some network segmentation examples?

You can use different approaches to implement network segmentation depending on your system’s requirements and needs. The most basic method is physical sub-network separation through LAN servers. The most common method though is perimeter-based segmentation using VLAN with firewall applications. That’s when you create Virtual LANs to divide a network. You also implement a firewall to keep paths and nodes secure. Lastly, the latest uprising technology is network virtualization where you implement mixed network segments called trust zones with flexible policies.

How is network segmentation implemented?

The first step to implementing network segmentation is to recognize your organization’s different domains. For example, you can divide your segments by departments: HR, accounting, sales, engineering, etc. Then, you need to choose the technology you’ll implement based on your network’s needs. Finally, you divide the network and isolate different segments all while enforcing boundaries to constrain traffic flow. You also want to implement automation to maintain the system and keep it updated.

What are the benefits of network segmentation?

Network segmentation improves your network’s functionality. It reduces congestion on different segments since it constrains traffic flow. It also isolates segments to improve your network’s security and localize cyberattacks damages. Another benefit is localizing and restricting local issues and breakdowns. Finally, you can use it to control users’ access by enforcing special permissions for access.

Resources

Firewall as a Service (FWaaS)

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Cyberattacks at Your Organization

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January 2022 Cybersecurity News Roundup

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