Network Segmentation

What do you do when you have a lot of a particular commodity, for example, money? You store or invest it into sections, right? You do not stash the entire amount in one particular section because that is bound to invite security threats among other problems.

Network segmentation is exactly like that but with networks. So imagine a complex network system containing sensitive data working to connect several systems simultaneously within a company. Now, segmentation creates subnets where designated systems can access designated parts of that network, and thus limited, required information only.

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What is network segmentation

Network segmentation is a network security technique that divides or compartmentalizes a particular network into smaller, isolated subnets. It uses mechanisms like switches or firewalls to protect and separate the networks and facilitate transitions from one network to another.

This system not only helps make networks more secure and efficient but also gives users greater control over traffic inflow in their respective networks. 

Zero trust approach

Traditional businesses have this outdated approach of implicit trust on everybody working in the company. However, as businesses continue to digitize themselves, it is difficult to keep track of all the systems involved and all the employees trying to access highly classified data through networks. 

Now, the zero trust approach is a cybersecurity principle that eliminates this implicit trust in employees, or rather, systems, and necessitates a trust through verification method. This means that any system seeking access to a network or even a part of it will have to complete a verification process and pass through certain security measures. This is the principle on which network segmentation in cybersecurity is implemented across systems.

Types of network segmentation

Network segmentation is of two main types as discussed below. Although the names itself are self-explanatory, there is a little more depth to each of the aspects:

1. Physical or hardware-based segmentation

Think of physical segmentation as sections in the same class. Each classroom is a different section with walls in between, right? However, that does not totally isolate the sections from being a part of the same grade. Similarly, physical segmentation involves using physical devices, or walls, like routers, switches, or firewalls to create separate network segments. Each segment is a separate department or aspect of the company that operates on its own dedicated hardware infrastructure, physically isolating traffic. Although this is basically a foolproof approach to security breaches, it can be costly to implement due to the need for additional networking hardware.

2. Virtual or logical segmentation

Now virtual segmentation is a little tricky. Think of this as chapters in a book. Can you see the chapters physically outside the book? No, but they exist, making it much easier to read the book and follow through on the plot. Similarly, virtual segmentation utilizes software-based techniques such as VLANs (Virtual Local Area Networks) and virtual routing to isolate traffic without requiring additional hardware. 

It creates separate virtual networks within a shared physical network infrastructure. Virtual segmentation is cost-effective and flexible, allowing organizations to dynamically manage and reconfigure network segments based on changing requirements.

Key components of network segmentation

If you look at a network segmentation diagram, there are several components that this cybersecurity infrastructure requires. Each component serves a specific purpose in maintaining segmented network architectures that companies can customize according to their needs.

1. VLANs (Virtual Local Area Networks)

VLANs are fundamental network segmentation tools that allow companies to logically separate systems into different broadcast domains. Each VLAN operates as a distinct virtual network, with its own set of traffic isolation rules and control mechanisms. 

VLANs can be configured based on criteria such as security levels, departmental hierarchies, and so on. They facilitate efficient use of network resources by reducing broadcast traffic and providing flexibility in network design.

2. Subnetting and IP addressing

Subnetting involves dividing a large network into smaller, manageable subnetworks (subnets) using IP addressing. Each subnet has its own range of IP addresses and serves as an individual network segment. 

Subnetting helps group network systems and puts an end to complicated routing problems. It also optimizes IP address allocation without compromising communication and data exchange within the systems in the same subnet.

3. Access Control Lists (ACLs)

ACLs are used to enforce security policies by filtering network traffic based on specified rules. These rules determine which packets are allowed or denied entry into a network segment. 

ACLs can be applied at physical segmentation mechanisms such as routers or firewalls to control traffic flow between VLANs or subnets. They enhance network security by restricting access to resources, preventing unauthorized communication, and mitigating potential threats such as unauthorized access or data breaches.

4. Firewalls and network zones

Firewalls play a critical role in network segmentation by establishing security boundaries, or zones, between different network segments. They verify and filter traffic inflow based on a set of predefined rules and deny access to any potentially dangerous malware. 

Now, since firewalls, like ACLs are specific to physical segmentation mechanisms, they can be deployed at network perimeters, between VLANs, or within data center architectures to create secure zones and regulate communication flow. If you implement firewalls strategically, your company can strengthen the network security posture and mitigate risks associated with inter-segment communication.

Advantages of network segmentation

The benefits of network segmentation are manifold in the sense that they contribute to an overall well-structured management of a company. Following are some of its advantages:

1. Prevents security threats

By compartmentalizing network structures and preventing access of unnecessary system and personnels to each segment, companies can mitigate any security concerns that arise. Had the network not been segmented, the malicious actor would have breached through the walls and infiltrated the network, and thus the functioning of the company as a whole. 

Now, to resolve this problem, the company would have to spend a lot more resources and time, thereby sacrificing business profit. This problem is easily solved with network segmentation.

2. Implementing the principle of least privilege

PoLP or the Principle of Least Privilege is a technological measure that keeps irrelevant users off the grid. This means that the company’s most important and high-profile networks are secured with limited access to only the required people and this enables the authorities to enforce more sophisticated security measures for them. 

Now, the network as a whole might not need these security measures and hence, once again, network segmentation saves the day with the proper allocation of resources stamped green on the checklist!

3. Traffic management and optimization

Network segmentation enables the user to segregate their network into small segments, thereby controlling the traffic inflow. Simply put, every segment in the network does not need the mechanisms to handle a heavy traffic inflow. Several in-house functions can easily sail with minimal maintenance and security. Thus, segmentation not only relieves the network of unnecessary baggage but also cuts down on security costs for the company.

4. Scalability

Network segmentation supports scalability by allowing organizations to expand or revamp specific segments without impacting the entire network. New segments, departments and modifications can be added, and existing segments can be adjusted to accommodate changes in business requirements.

How to implement network segmentation

Implementing network segmentation involves several key steps to design, deploy, and manage segmented network architectures effectively. Here's a structured approach to implementing network segmentation:

1. Assess network requirements

When you install a network segmentation infrastructure, the first step is to identify the company objectives. What do you need this infrastructure for? Identify this pain point first and then list out the security requirements and the operational needs to help the segmentation strategy. Chart out the network segments that need to be isolated with enhanced security measures.

2. Define segmentation policy

The next step would be to establish segmentation policies based on identified requirements. Define the specific criteria for compartmentalizing this network traffic, such as user roles, data sensitivity, application hierarchy, and so on. Specify access control rules, traffic filtering criteria, and communication protocols between segments.

3. Design segmentation architecture

After you have a policy in place, it is time to set up the infrastructure. Develop a segmented network architecture that aligns with defined policies and requirements. Determine the appropriate segmentation techniques, such as VLANs, firewalls, routers, or subnetting to implement isolation between network segments.

4. Configure network devices

Configure network devices (e.g., switches, routers, firewalls) to enforce segmentation policies. Implement VLANs, assign IP subnets, and configure access control lists (ACLs) on routers and firewalls to control traffic flow between segments.

5. Deploy security controls

After having the architecture in place, tighten the system with firewalls, intrusion detection/prevention systems (IDS/IPS), verification frameworks, and endpoint security solutions to monitor and protect segmented network segments. Implement encryption and authentication mechanisms to secure inter-segment communication.

6. Test and validate segmentation

Conduct testing to validate the effectiveness of segmentation policies and controls. Perform security assessments, penetration testing, and traffic monitoring to identify vulnerabilities and ensure compliance with segmentation policies.

7. Implement monitoring and maintenance

Last but not least, remember to implement continuous monitoring and maintenance practices to manage segmented networks effectively. Monitor network traffic, analyze security logs, and update segmentation policies based on evolving threats and business requirements.

Use cases and examples of network segmentation

Network segmentation offers various use cases and examples across different industries. Here are several practical network segmentation examples where compartmentalization is beneficial:

1. Compliance with industry standards:

Large to small-scale retail organizations segment their financial network to comply with Payment Card Industry Data Security Standard (PCI DSS) requirements. They isolate payment processing systems (POS terminals, payment gateways) from other network segments to protect cardholder data and reduce the scope of compliance audits. 

These chains implement VLANs to compartmentalize and protect POS systems from guest wi-fi networks and any other breaches that might jeopardize client information during card or online transactions.

2. Healthcare data protection:

Hospitals use network segmentation to safeguard sensitive patient information and medical records. This is again in compliance with Health Insurance Portability and Accountability Act (HIPAA) regulations if the provider is certified. 

Even if they aren’t, they still have the liability to safeguard and separate electronic health record (EHR) systems and medical devices to prevent unauthorized access and data breaches. This is why hospitals create separate VLANs for patient care devices such as monitors and pumps which outflow the data directly to the administrative staff computers to maintain data confidentiality and integrity.

3. Industrial Control Systems (ICS) security

Industrial organizations segment their operational technology (OT) networks to protect critical infrastructure from cyber threats. They isolate manufacturing equipment, supervisory control and data acquisition (SCADA) systems, and enterprise networks to minimize the impact of cyberattacks on production processes.

4. Guest Wi-Fi access in hospitality management

Hospitality businesses use network segmentation to provide secure guest Wi-Fi access while protecting internal resources at the administrative level. These compartments segregate guest networks from employee networks and back-office systems to prevent unauthorized access to sensitive data.

5. BYOD (Bring Your Own Device) Policies:

Since the time of the pandemic, organizations have implemented network segmentation to support BYOD initiatives. This definitely cuts down on the company’s costs and secures personal devices accessing corporate resources. They create separate network segments for employee-owned devices, enforcing access controls and security policies.

Challenges and considerations

Network segmentation isn’t always a bed of roses. There are certain drawbacks or rather, challenges to installing this infrastructure as I’ll discuss below:

1. Complexity

Building a network segmentation architecture isn’t the simplest thing ever. It requires all the segments to be separated, and yet connected in sync with each other. This poses a problem if network administrators aren’t quite equipped with monitoring tools and the necessary skills to maintain the network.

2. Resource overhead

Segmenting networks will require additional investments in hardware or software depending on the type of segmentation you opt for. These costs are definitely justified in the long run, but it can feel overwhelming to invest in firewalls, routers, VLANs, and other equipment all at once in addition to the maintenance and specialist procurement costs.

3. User experience

Due to several segmented network bylanes, user experience on the front-end might be hampered. This can be managed once the segments and their security systems are compatible with each other. However, the idea is that the system should not be too restrictive or misconfigured so as to not disrupt the workflow.

Wrapping up

Network segmentation is one of the many security protocols that make businesses strong today. With an in-depth understanding of these concepts as a whole, you can too design networks that are capable of transacting sensitive data without the threat of breaches.

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FAQS

1. What are the ways of network segmentation?

Network segmentation can be done in two ways- physical and logical. Physical segmentation uses hardware to separate the networks while virtual or logical segmentation relies on software-based compartmentalization.

2. Is network segmentation the same as subnetting?

No, network segmentation and subnetting are related concepts but not the same. Subnetting is when you divide a network into smaller subnetworks using IP addressing, while network segmentation is completely separating network segments based on different criteria.

3. What is network segregation vs segmentation?

Network segregation is separating different types of traffic or users within the same network while network segmentation is a broader strategy that divides a network into distinct segments based on specific criteria like security, hierarchy, or functionality.

4. What is data segment in networking?

In networking, a data segment refers to a portion of data transmitted between network endpoints. This is often encapsulated within a network layer protocol like TCP or UDP.

5. What are the 3 main purposes of network segmentation?

The three main purposes of network segmentation are– dismissing security threats, enabling smooth traffic management, and streamlining scalability drives across the company.

6. What are the two network segments?

The two network segments are physical and virtual. Although they perform the same function, physical segments use hardware measures like firewalls and routers to get the job done and logical segments use VLANs to separate networks.

7. What is the main purpose of segmentation?

The main purpose of network segmentation is to monitor traffic flow into the networks and prevent any data breeches or security threats, thereby safeguarding sensitive data.

8. What are the three major types of segmentation methods?

The three major types of segmentation methods in networking are logical or VLAN (Virtual Local Area Network) segmentation, subnetting, and firewall-based or physical segmentation. 

9. What are the disadvantages of network segmentation?

The advantages of network segmentation definitely outweigh the disadvantages which are– the complexity of installation, the risk of hampering user experience and incurring additional costs to top the security measures already in place.