Network Isolation: What it is & How it Works for Security

Network isolation is a design approach that divides or partitions a network into separate segments or subnets, each acting as its own small network. This tactic is used to improve security and performance within a larger network structure.

This concept is particularly relevant in complex environments like financial institutions, healthcare, enterprise and college campuses, where the need to protect sensitive data and ensure reliable network performance is paramount. By isolating network segments, organizations can better manage and secure their digital infrastructure.

How does network isolation work?

Network isolation is a process that allows IT to divide or partition a network into various segments or sub-networks. This was done to minimize a broadcast domain and later to try and improve the security and manageability of the network.

VLANs traditionally played a crucial role in network isolation by allowing network administrators to group devices on different physical LAN segments into the same virtual network, effectively segmenting the network without the need for separate switch hardware.

But as a security mechanism they represent a significant drawback:

1. They allow for devices within the same VLAN to communicate with each other in Layer 2, enabling potential spread of malware and ransomware software.
2. In order to ensure proper security of the devices within a VLAN, separate set of static ACLs need to be assigned to each given corporate access policies.
3. These policies will then have to be orchestrated with an external NAC server to ensure that they dynamically are assigned given user and device locations and movement patterns. Needless to say, this can get quite complex with increasing number of user and device types, locations and size of the overall network.

Instead of VLANs as a network security construct, a Nile network utilizes Layer 3 only traffic forwarding with zero trust isolation of each authentication and authorized device. After mandatory secure and authenticated onboarding, each device is isolated from one another, eliminating the potential for malware proliferation.

Within the Nile Access Service, each Nile network is essentially treated as a collection of such isolated segments given user, device, application and location specific network access policies. IT adminstrators can easily provision these segments with a few clicks, orchestrating their provisioning within the full stack of Wi-Fi access points and wired switches – without having to configure multiple hardware and software products separately, as used to be the case with traditional product-centric infrastructure.

Industry’s first campus zero trust approach by Nile – where zero trust networking principles are extended to campus and branch locations – not only enhances network security but also aids in traffic management. By controlling and limiting traffic flow between these segments, network isolation safeguards against unauthorized access and mitigates the spread of security breaches within an organization’s network.

It forms a core element of enterprise network security, ensuring that different departments or user groups have access only to the network resources that are essential for them. By utilizing a Nile network, many organizations report that they are able to quickly tackle network security audits, easily translate corporate policies to network segmentation rules, and reduce cyber insurance costs during the insurance renewal cycles.

Traditional techniques for network isolation

Network isolation has so far been implemented through various techniques in traditional network architectures, each becoming obsolete with the arrival of zero trust networking principles.

Physical separation

Physical separation involved using distinct hardware for different network segments. This method was highly secure as it physically restricted access between different parts of the network. It was commonly used in environments where utmost security is required, like in areas handling sensitive data. This of course added to the complexity and cost of operations.

IP subnetting

IP subnetting divided a network into smaller, more manageable sub-networks. This technique simplified network management and enhanced security by limiting the scope of broadcast domains and reducing network congestion. Subnetting was a flexible approach to network isolation, allowing for efficient use of IP addresses – but again brought a number of complexities as the number of user profiles, device types and locations increased within a network.

Virtual Local Area Networks

VLANs provided logical separation within the same physical network infrastructure. By segmenting a network into VLANs, network administrators could group devices according to function, department, or security level. This flexibility made VLANs a popular choice but overtime – due to reasons highlighted in the previous section – VLANs became difficult to manage across enterprise networks as a way to ensure proper isolation. At this point, it is clear that utilizing traditional VLANs to enforce network access policies has outlived its usefulness.

Access control lists

ACLs were used to enforce access and security policies in network devices like routers and switches. With rules that permit or deny traffic between network segments, ACLs provided a layer of security that helped in controlling and monitoring network access. ACLs could be very complex and difficult to maintain. By extending zero trust networking principles to campus and branch networks as part of the Nile Access Service, static ACLs and management of their respective policies with a Network Access Control (NAC) appliance become a thing of the past.

Firewall rules

Firewalls serve as a barrier between trusted and untrusted networks. By implementing firewall rules, organizations can control incoming and outgoing network traffic based on an applied rule set. This is essential for protecting network resources from unauthorized access and cyber threats. After each device is isolated in Layer 3 within a Nile network, each of the respective network segments can be secured with firewall enforcement (e.g. Nile Access Service and Palo Alto Networks integration), significantly strengthening the network security perimeter.

Benefits of network isolation

Network isolation is a strategic approach that brings multiple advantages to an organization’s network infrastructure.

Enhanced security

The foremost benefit of network isolation is a significant enhancement in security. By dividing the network into separate segments, it becomes more challenging for unauthorized users to access sensitive areas. This segmentation is essential in limiting the scope and impact of potential security breaches.

Improved network performance

Network isolation helps in reducing congestion on the network. By segmenting traffic, organizations can ensure that critical applications receive the bandwidth they require, leading to improved overall network performance and reliability.

Simplified compliance

With the proper network isolation, complying with data protection regulations becomes more manageable. Organizations can isolate sensitive data within specific network segments, making it easier to apply security measures that meet regulatory standards.

Granular network management

Managing a segmented network can be easier than managing a large, unified one. Network isolation allows for more precise control over each segment, enabling administrators to tailor settings and policies to the specific needs of each network subdivision.

Reduced risk of widespread outages

Isolating segments of the network means that a problem in one area is less likely to affect the entire network. This containment is crucial for maintaining operational continuity and reducing the risk of widespread network outages.

Applications of network isolation

Network isolation is not just a theoretical concept; it has practical applications in various scenarios, especially in complex and dynamic environments.

Securing sensitive data

Network isolation can provide an additional layer of security in environments where sensitive data is handled, such as research departments, healthcare and administrative departments where user information is paramount. Isolating these areas from the rest of the network ensures that sensitive information remains protected.

Facilitating specialized departments

Certain departments may have specific network requirements, such as higher bandwidth or specialized software. Network isolation enables these departments to have a tailored network environment that meets their unique needs without affecting the rest of the campus network.

Managing guest access

Most organizations often need to provide network access to guests, such as contractors, customers, patients, travelers and visiting lecturers or students. Network isolation allows for creating a separate guest network, ensuring that guests have Internet access without compromising the security of the main network.

Nile’s Secure Guest Service offers a seamless and easy-to-use solution for managing guest access across any size network. By tunneling guest traffic to the nearest Nile Point of Presence (PoP), Nile’s Secure Guest Service effectively isolates guest traffic from internal network resources, enhancing security and reducing the risk of sensitive data exposure. This approach eliminates the need for complex network configuration, end user supplicants and the maintenance of separate DHCP servers and anchor controllers, simplifying network management for IT teams.

Examples of network isolation

Network isolation can be illustrated through various real-world examples, especially in complex environments like enterprise networks and educational institutions.

Corporate environments

In corporate settings, network isolation is used to separate critical business systems from general office networks. This separation ensures that sensitive financial data, HR related or proprietary information is not accessible from less secure areas of the network.

Educational campuses

On college campuses, network isolation is key for protecting student records and research data. Separate networks for administrative purposes, student access, and guest use are common, each with tailored security measures.

Healthcare facilities

Healthcare facilities use network isolation to safeguard patient information and ensure HIPAA compliance. Critical medical systems, such as those for patient records and diagnostic equipment, are often isolated from the general network to prevent unauthorized access and data breaches.

Best practices for network isolation

To effectively implement network isolation, following best practices that ensure security, efficiency, and manageability is crucial.

Plan and document

Before implementing network isolation, it’s essential to carefully plan the network design and document each step. This process should include identifying network resources and categorizing them based on their role, sensitivity, and required security level.

Adhere to the least privilege principle

When designing network access policies, zero trust principles or the idea of least privilege should be strictly followed. This means granting network users only the permissions they need to perform their tasks, minimizing potential security risks.

Ongoing monitoring

Continuous monitoring and regular audits are vital for maintaining the health of a segmented network. It’s important to quickly identify and address any anomalies or suspicious activities. Automation should play a key role when exploring new solutions.

Maintain system updates

Keeping each system within the network updated with the latest patches and software versions is crucial to mitigate potential vulnerabilities. The automation of security patch updates is an integrated part of the Nile Access Service, eliminating manual software update cycles.

Regular testing

Conduct regular penetration tests and vulnerability assessments to verify the effectiveness of isolation measures and to identify any potential weaknesses.

Network redundancy

Make sure that network segmentation doesn’t compromise system availability. Implement adequate redundancy to ensure continuous business operations.

Introducing zero trust isolation

While traditional network segmentation has been around for decades, Nile’s Access Service introduces a new approach that eliminates the complexity associated with VLANs and ACLs. Nile’s Access Service orchestrates user/device level segmentation in Layer 3 after mandating zero trust authentication and authorization across wired and Wi-Fi network access.

Nile’s Secure Guest Service simplifies the process of network isolation for visitors by transferring the guest traffic to Nile’s cloud PoP. By automatically isolating guest traffic and tunneling it directly to the Internet, this service reduces the need for complex network configurations and specialized hardware and software, decreasing both initial setup costs and ongoing operating expenses.

This approach streamlines network management and mitigates potential security risks associated with employee, IoT and guest access by leveraging industry’s first campus zero trust implementation.