What is Network Segmentation?

Network segmentation is an architecture that divides a network into smaller sections or subnets. Each network segment acts as its own network, which provides security teams with increased control over the traffic that flows into their systems.

With network segmentation, businesses can prevent unauthorized users from gaining access to their most valuable assets, such as customer data, financial records, and intellectual property (IP). These assets are often located across organizations’ hybrid and multi-cloud environments, which means it is vital to secure all locations against cyberattacks.

Network segmentation is also commonly referred to as network segregation but differs from other related concepts such as microsegmentation, internal segmentation, and intent-based segmentation.

 

Network Segmentation vs. Microsegmentation

Microsegmentation takes a more granular approach to segmenting networks through virtual local-area networks (VLANs) and access control lists. It applies policies to individual workloads, which offer enhanced resistance to attacks.

Microsegmentation builds smaller, more secure zones on a network, enabling the organization to create policies that minimize flows between workloads. This limits a hacker's ability to move between compromised applications and reduces the complexity of managing network segmentation.

Network Segmentation vs. Internal Segmentation

Traditionally, network segmentation was relatively simple, with organizations using static IP addresses and ingress and egress ports that made the process easy to define. However, with the growth of distributed networks and multi-cloud environments, IP addresses are constantly changing. As a result, network segmentation has to evolve with the changing landscape to prevent cyber criminals from gaining access to business systems, becoming part of a trusted network, and remaining under the radar. 

Internal segmentation enables organizations to segment their network and infrastructure assets regardless of their location and whether they are on-premises or on multiple cloud environments. The business can then establish dynamic and granular access by continuously monitoring the trust level and adapting its security policies accordingly. Critical IT assets are isolated to ensure that any threats are quickly detected and risks are prevented using methods such as analytics and automation.

Network Segmentation vs. Intent-based Segmentation

Businesses using network segmentation can manage their assets through network semantics. However, they may find that this option does not provide the level of security they require. That is because there are no rules or mechanisms in place to manage necessary tasks like admission control, authentication, and assessing trust.

Intent-based segmentation solves this problem by identifying where segmentation is applied, how trust is established, and what security inspections need to be applied to traffic. It combines traditional segmentation and zero-trust principles, which offer an integrated security architecture that adapts to organizations’ changing requirements. Intent-based segmentation enables them to detect and mitigate advanced threats and grant variable access on a need-to-know basis.

Intent-based segmentation covers an entire network and its assets, including all endpoints and devices, which makes it more comprehensive than traditional solutions—or a flat network. It also uses existing mechanisms, such as identity-based network tools and business logic. This enables businesses to allow or prevent access to network resources based on risk and trust assessments following suspicious user behavior and actions.

Organizations can also manage what level of security inspection traffic requires and encrypt all traffic as it arrives at network speed. This is vital as trusted users can become the victim of a malware attack without knowing it and provide a route into the network for hackers.

Network Segmentation and the Zero-trust Model

Traditionally, organizations built their security strategies based on a trusted network perimeter. This used the theory that everyone working within the four walls of the business was trusted and was treated as such behind the company firewall. However, with people increasingly working remotely and from various devices, this approach is no longer effective.

Instead of protecting the network perimeter, the zero-trust model takes the “never trust, always verify” approach to ensure only the right people have the right level of access to the right resources in the right context. Access is continuously assessed without adding friction, such as login requests, to users.

User credentials can be managed by identity and access management (IAM) solutions that protect sensitive data and people. IAM is a framework of policies, processes, and technologies that enable organizations to manage their digital identities and user access to critical information and resources. It assigns roles to users to ensure they have the right level of access to resources and networks, which boosts security, offers greater agility, and reduces costs. 

IAM enhances the user experience while keeping the business secure. It does this with tools like single sign-on (SSO) and multi-factor authentication (MFA), which quickly and easily verify and authenticate users. It also automates time-intensive tasks that are susceptible to human error, which is key as businesses embrace mobile and remote working and cloud adoption.

Organizations also now need to be able to see and protect a wide range of devices that sign in to their network. As a result, network access control (NAC) solutions are assisting with bring-your-own-device (BYOD) policies and accommodating Internet-of-Things (IoT) devices. This increases the visibility of every device and user that joins the network, limits areas of the network that devices can access, and automates responses to speed up event reaction times.

 

Benefits of Network Segmentation

Network segmentation offers many benefits for businesses. These include reducing the attack surface, preventing attackers from achieving lateral movement through systems, and improving performance levels. The most prominent advantages of network segmentation include:

Security

Segmentation improves security by preventing attacks from spreading across a network and infiltrating unprotected devices. In the event of an attack, segmentation ensures that malware cannot spread into other business systems. Furthermore, passing different devices through a firewall enables organizations to enforce least privilege—allowing just enough access for users to perform their jobs—and inspect the devices for potential threats.

A good example of how this works is segmentation preventing a malware attack on a hospital from reaching mission-critical devices that do not have security software installed.

Performance

Network segmentation reduces the congestion that often results in performance drop-off. This is particularly important to resource-intensive services like online gaming, media streaming, and videoconferencing.

For example, by reducing network congestion through segmentation, businesses that rely on videoconferencing tools to carry out meetings can prioritize the performance of their applications. Congestion could result in packets being lost, which would delay the stream, causing the sound and video quality to become jumpy and difficult to understand. But segmenting network traffic can guarantee high-quality video meetings.

Monitoring and Response

Network segmentation simplifies the process of monitoring network traffic. It helps an organization quickly detect suspicious activity and traffic, log events, and record connections that have been approved or denied. Splitting subnets allows organizations to monitor the traffic going in and out of them, which is less tough compared to monitoring the entire network. As a result, security becomes easier, and the chances of a threat being missed are reduced.

Use cases this could apply to are for organizations that need to comply with the Payment Card Industry Data Security Standard (PCI DSS). Effective traffic monitoring is crucial to preventing credit card data from being compromised and minimizing the complexity of a PCI DSS assessment.

Types of Network Segmentation

Network segmentation enables an organization to break their systems down into smaller sections. They can do this physically and logically.

 

Physical Segmentation

Physical segmentation breaks networks down into multiple physical sections or subnets. A firewall acts as the gateway and controls traffic that comes in and out of the network, along with hardware like access points, routers, and switches. Physical segmentation is commonly seen as a simple method, but it can frequently become expensive and create unforeseen issues.

Logical Segmentation

Logical segmentation is a more popular way of breaking the network into smaller, more manageable sections. It often does not require the organization to invest in new hardware or wiring, which is helpful in reducing costs and is more flexible.

A logical segmentation approach deploys existing network infrastructure concepts using VLANs or a network addressing scheme. VLANs automatically send traffic to the most appropriate subnet, while a network addressing scheme is more complicated and theoretical. 

Achieving Network Segmentation: How Fortinet Can Help

Network segmentation is vital for organizations to secure their resources, systems, and users, as well as minimize the risk of attackers gaining access to their critical corporate information. Achieving this is reliant on deploying traditional technologies that businesses have used to segment their networks for years with modern alternatives that provide protection from more advanced threats.

Traditional technologies like VLANs, which improve traffic management, and access control lists, which add a layer of security by acting as a firewall across subnets, help businesses to segment network traffic. They need to be paired with a modern solution like the FortiGate next-generation firewall (NGFW), which allows organizations to filter network traffic and provides advanced visibility. This, in turn, enables them to identify and prevent advanced threats and malware. FortiGate not only blocks malware but also ensures businesses are future-proofed and receive updates that keep them in line with the evolving threat landscape.

For high threat protection performance and modern network segmentation approaches, segment your network with FortiGate.