What is network segmentation: understanding the basics

Network segmentation is a security technique that divides a large network into smaller subnetworks or segments. This security technique improves network performance, enhances network security and facilitates network management. Many IT experts understand the benefits of isolating different parts of a network, but it seems that few organizations have actually fully implemented the practice. In this blog, we discuss the basics of network segmentation and its importance.

Brief explanation of network segmentation

Network segmentation means dividing a network into smaller segments or subnetworks. Each has its own security and performance characteristics. This technique allows more detailed control over a network. It also helps minimize the impact of security breaches and other network interruptions.

The importance of network segmentation

Network security is of paramount importance in today's digital world. Because of the increase in the number of connected devices and the increase in cyber attacks, it is essential to have a cyber security strategy in place. Network security reduces the attack surface and minimizes the impact of a security breach. It is easier to monitor, control and manage network traffic by dividing a network into smaller segments. This improves overall network performance and stability. Network segmentation also allows for better scalability and management of network resources. This makes managing and maintaining the network infrastructure easier. Network segmentation is a critical component of network security and management. Organizations can improve their network security by understanding the importance and basics of network segmentation. In this way, they can improve their performance and better manage their network resources.

What is network segmentation?

Each of the segments created with network segmentation is isolated from the rest, allowing more detailed control over network traffic and security. This helps minimize the impact of security breaches, network failures and other disruptions.

Definition and explanation of network segmentation

Network segmentation is the division of a large network into smaller segments or subnetworks with their own security and performance characteristics. This improves network security and performance. Network segmentation makes it easier to manage and maintain a network. Routers, firewalls and other network devices are used to isolate different segments of the network.

Types of network segmentation (physical, logical)

There are two main types of network segmentation: physical and logical. Physical network segmentation means physically dividing different segments of the network into separate parts of a building or different buildings. Logical network segmentation means dividing a network logically using software and hardware, even if everything is in the same physical space. While physical network segmentation is typically used in larger organizations with multiple physical locations, logical network segmentation is used in smaller organizations or in situations where physical separation is not practical. Logical network segmentation is usually simpler and faster to implement. Network segmentation is important to improve the security and performance of modern networks. It is easier to monitor, control and manage network traffic when you divide a network into smaller segments. This improves the overall stability and security of the network.

Network segmentation versus microsegmentation

When it comes to network security, both network segmentation and microsegmentation policies must be implemented. Network segmentation aims to limit north-south traffic between different networks, while microsegmentation provides protection from east to west within a network. That means limiting access to all devices, servers and applications that communicate with each other. Microsegmentation is a more detailed approach for traffic within the network. While network segmentation can be seen as an overarching security policy for the entire infrastructure.

Why is network segmentation important?

Network segmentation can be a chore to set up, which is why many companies may not have it set up for their network. It requires detailed information about the network infrastructure, strong security controls and major adjustments to the network architecture and business processes. This way, segments can be created without leaving gaps. Implementing network segmentation is not always easy, but it is a crucial aspect of modern network design and management. The benefits of network segmentation far outweigh the challenges. It enhances network security, improves network performance and facilitates network management.

Improving network security

The main benefit of network segmentation is improved security. Dividing a network into smaller segments reduces the attack surface and minimizes the impact of a security breach. Strong network segmentation can help prevent attackers from escaping from a system before the breach is mitigated and their access shut down. This minimizes the damage caused by a breach. It can also buy you extra time during an attack. An attacker may be able to break into a segmented part of the network, but it will take longer or it may even be impossible to gain access to the entire network. Network segmentation makes it easier to protect your most sensitive data. It creates a layer of separation between servers with sensitive data and anything outside the network. This reduces the risk of data loss or theft. Each segment can be monitored and managed separately, making it easier to identify and mitigate inside and outside threats. Strong network segmentation makes it easier to implement and enforce security policies, such as firewalls, access control lists and encryption, to protect your most sensitive data.

Improving network performance

Another important benefit of network segmentation is improved network performance. By dividing a network into smaller segments, it is possible to isolate heavy traffic from other parts of the network. This improves overall network performance and stability by reducing the number of hosts and users within a segment. It also makes managing network resources and allocating bandwidth easier, further improving network performance.

Facilitating network management

Network segmentation makes it easier to manage and maintain the network infrastructure. By dividing a network into smaller segments, it is possible to isolate different parts of the network and manage them separately, reducing the risk of network disruptions. Network segmentation also makes it easier to manage and allocate resources such as bandwidth and processing power. This improves overall network efficiency and scalability. In short, organizations can better monitor, control and manage network traffic, improving the overall security and stability of their network.

How does network segmentation work?

We then examine the steps involved in network segmentation and the role of VLANs, routers and firewalls.

Steps involved in network segmentation

The steps involved in network segmentation include:

1. Define network segments: The first step in network segmentation is to define the different segments of the network, taking into account factors such as performance, security and management requirements.
2. Determining Network Topology: The next step is to determine the network topology, which will help ensure that network segmentation is implemented in a way that meets the specific needs of the organization. By network topology, we mean the physical and logical arrangement of nodes and connections in the network. Nodes can be switches, routers and software with switch and router functions.
3. Creating the segments: The next step is to create the segments using networking technologies such as VLANs, routers, firewalls and more. Choose the right tools, considering factors such as cost, scalability and performance.
4. Configure the segments: The next step is to configure the segments to ensure that they are properly isolated from each other and that performance and security requirements are met.
5. Monitor and maintain the segments: The final step is to monitor and maintain the segments to ensure they continue to meet performance, security and management requirements.

The role of routers, VLAN segmentation, segmentation controls, SDN segmentation and DMZs

There are several ways to segment your network. Typically, segmentation is performed through a combination of firewalls, Virtual Local Area Networks (VLANs) and Software Defined Networking (SDN).

Routers

The next most important technology in network segmentation are routers. They help to route traffic between different segments of the network. Routers use routing tables to determine the best path for network traffic. They can also be configured to enforce security policies and restrict traffic flow between segments.

VLAN segmentation

The VLAN or Virtual Local Area Network is an important technology that can be used to segment networks. They allow multiple network segments to exist on the same network but be logically separated. VLANs are created by tagging network traffic, which helps to isolate different segments of the network. While this approach effectively segments the network, they are often complex to maintain and often require extensive re-architecting.

Segmentation checks

A segmentation control is any device, process or system used to create network segments to isolate assets on the network. Segmentation controls must be tested to verify their effectiveness against cyber attacks. These tests verify how well segmentation controls isolate different network zones, and they are often performed during larger pen tests. In this way, organizations can verify that their network segmentation meets critical security standards.

Firewalls

Firewalls play an important role in network security and network segmentation because they can be used to filter traffic between two separate nodes in a network. They help protect network segments from external threats by controlling and monitoring network traffic. Firewall can allow or block specific types of network traffic, and they can be used to enforce security policies and prevent unauthorized access to network segments. Firewall functionality in the cloud is also called FWaaS or Firewall as a Service. This can provide financial, network performance and security benefits.

Access control list (ACL).

Another management for network segmentation is the Access Control List (ACL). ACLs are permissions associated with an object on the network. These permissions specify who can access and use the object and what the object is allowed to do. ACLs can be restrictive but also very effective.

SDN segmentation

SDN segmentation or software-defined network segmentation isolates internal network traffic using software-defined network segments and predefined rules. It is essentially network segmentation without the need to change the infrastructure. SDN segmentation means establishing security policies for individual or logically grouped applications, regardless of their physical location. It is a more modern approach to network segmentation that involves an SDN-automated network overlay. A network overlay is a network on top of another network, removing the hard-coded limitations of a physical network. This approach is complex and must be implemented correctly for successful microsegmentation. In short, network segmentation can be achieved using these technologies. By understanding how these technologies work, organizations can better plan and implement network segmentation strategies that meet their specific needs.

DMZs

DMZ stands for a demilitarized zone in network security. It can be a physical or logical subnet (segment) that separates a LAN or Local Area Network from other untrusted networks. Usually this means it is separated from the public network. DMZs are also called perimeter networks because they are defined by two strictly segmented boundaries. One boundary between the DMZ and the untrusted external network and another between the DMZ and the internal network. Usually, these boundaries are firewalls that isolate assets from the internal network and from untrusted external networks.

Implementation of network segmentation

It is important to properly implement network segmentation to achieve the desired benefits when it comes to network design and management. We explore best practices for network segmentation, available tools and factors to consider during implementation.

Best practices for network segmentation

It is important to follow best practices to achieve the desired results when implementing network segmentation. Some best practices for network segmentation include:

1. Follow the principle of least privilege: The principle of least privilege is one of the key principles of zero trust. This means denying network access at any level and requiring all parties to authenticate and verify before accessing other parts of the network. It is important to minimize who and what has access based on their actual need. This means that not everyone needs access to every part of the network. By following the principle of least privilege, you can prevent hosts, services, users and networks from accessing data and functions outside their direct responsibility. Only users with the appropriate permissions can access the data within that network. Through zero-trust architecture, network administrators can identify bad actors or unauthorized parties trying to infiltrate systems. This strengthens overall network security and makes it easier to monitor and track traffic across the network.
2. Limit third-party access points: It is also important to limit third-party access to your network to minimize exploitable access points. Providing too much third-party access remains a significant vulnerability for organizations. It is important to assess the security and privacy practices of third parties and ensure they have just enough access to carry out their designated responsibilities, and nothing more. Third parties can be isolated by creating unique portals with customized access controls for each party.
3. Check and monitor your network continuously: During the segmentation process, network traffic and performance should be continuously monitored to ensure that the architecture is secure and that there are no gaps or vulnerabilities. This way, you can quickly identify and isolate traffic and security problems. Regular audits and penetration tests to uncover architectural weaknesses are also important. This allows organizations to re-evaluate and adjust the effectiveness of their current security policies. Audits and monitoring are also particularly important when your business grows and your network architecture may no longer meet your needs. This can help you adapt the design of your network segmentation to meet your new needs, optimal performance and security.
4. Visualize your network: To design an effective and secure network architecture, you must first understand why your users are, what components your network consists of and how all systems relate to each other. It would be difficult to plan and achieve the desired state without a clear picture of your current state. Determine who needs access to what data so that you can successfully map out your network.
5. Create simpler legitimate data paths: You should evaluate and plan your architecture design based on the paths users will take to connect to your network. It is important to create secure access points for your users, but you must also be mindful of how bad actors may attempt to illegally access those same segments. Legitimate paths should be easier to navigate than illegal paths to improve your security. For example, if you have firewalls that sit between your vendors and the data they need to access, but only some of these firewalls are able to block malicious actors. This means you need to rethink your architecture.
6. Identify and label asset values: Before starting a network segmentation process, you need to inventory your assets and assign values to them. These assets should be organized according to their importance level and data sensitivity. An asset can be anything from an Internet of Things (IoT) device to a database. Separating these lower- and higher-value assets while maintaining a comprehensive list of assets allows for an easier transition and implementation of a network segmentation strategy.
7. Combine similar network resources: After documenting the inventory of your assets, begin grouping similar network resources into separate databases. This saves time and reduces security overhead. By categorizing data by type and degree of sensitivity, you can quickly apply security policies while protecting your data more efficiently. This practice also makes it easier to determine which networks have priority over others. This makes network monitoring and filtering more accessible.
8. Don't segment your network too much or too little: A common mistake when implementing network segmentation is over-segmenting a network or under-segmenting a network into too few segments. Organizations often incorrectly assume that as much segmentation as possible ensures the highest level of security. You must have sufficient resources to manage and monitor multiple networks without sacrificing employee productivity. Oversegmentation causes employees to go through multiple access points to access data. This leads to workflow inefficiencies and restricts traffic flow. It can also create more vulnerabilities because it takes longer to implement security updates for each individual network. Too many segments create unnecessary complexity, make it harder to manage the entire network and increase the risk of errors. On the other hand, undersegmentation can also prove ineffective if there is not enough separation between each system.
9. Implement endpoint security and protection: Endpoint devices are often the target of cyber attacks because they are often unsecured and not adequately protected. One hacked device can create an entry point for hackers to gain access to the entire network. Technology such as Endpoint Detection and Response (EDR) allows organizations to provide an additional layer of security by proactively monitoring indicators of attacks and indicators of compromise.

Choosing the right tools for network segmentation

There are many tools available for network segmentation. We will divide them into two groups, hardware-based solutions and software-based solutions. Examples of hardware-based solutions include routers, firewalls and switches. Software-based solutions include VLANs and network access control (NAC). It is important to consider factors such as cost, scalability, performance and ease of use when choosing your network segmentation tools. In the past, multiple VPNs have been used to segment networks and secure access to sensitive systems. This presents a number of problems, such as:

• Scalability: As you use VPNs, you eventually become increasingly tolerant of keeping the list of rules to a manageable size.
• Performance impact: VPNs make networks more complex and this can increase latency and affect application performance.
• Insufficient audit trails: there are not enough details about who performed each query or job, just that a session took place.

Factors to consider when implementing network segmentation

There are several factors to consider when implementing network segmentation, including:

1. Network size and complexity: It is important to know the size and complexity of a network to determine which tools and techniques are best suited for network segmentation.
2. Security requirements: Security requirements define the types of network segments to be created and the security policies to be implemented.
3. Performance requirements: It is important to know the exact performance requirements because they determine the types of network segments to be created and the types of tools to be used to manage network traffic.
4. Network management requirements: Network management requirements define the types of tools to be used to manage and maintain network segments.

Network segmentation is a critical aspect of network design and management, so it is important to implement it correctly to achieve the desired results. Organizations can implement network segmentation strategies that meet their needs by following best practices, choosing the right tools and considering the factors involved in network segmentation.

Conclusion

We have now discussed the importance of network segmentation and its benefits to organizations.

Summary of key points

In summary, we discussed the following key points:

• The importance of network segmentation
• The benefits of network segmentation: enhanced security, improved network performance and simplified network management
• Different approaches to network segmentation: VLAN segmentation, routers, segmentation controls, DMZs and SDN segmentation

Future prospects for network segmentation

Network segmentation will only become more important as threats in the digital landscape continue to evolve. Organizations must ensure their networks are secure and protected from potential attacks as they become increasingly dependent on technology.

Final thoughts and recommendations

In short, network segmentation is an essential aspect of network security that should not be overlooked. Organizations can improve security, enhance network performance and simplify network management by dividing their network into segments. You should conduct regular security assessments and adopt the latest network segmentation techniques to stay ahead of evolving threats.

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