What is Network Segmentation?

A network can be divided into several segments or subnets, each of which functions as a separate little network, using a technique called network segmentation. This enables network managers to manage traffic between subnets according to detailed regulations. Segmentation is a technique businesses use to strengthen security, increase performance, and monitor systems more effectively.

The so-called “crown jewels” of the business, such as customer private details, corporation financial information, and highly private intellectual property, may no longer be accessed by unauthorized users, whether they be interested insiders or hostile attackers, thanks to network segmentation. Currently, these resources are commonly dispersed across hybrid and multi-cloud settings and public, private, and software-defined networks (SDNs), all of which must be protected from attacks. It’s first required to think about trust in network security to comprehend how network segmentation is used for protection.

The Trust Assumption

The invisible boundary separating the outside world from the data essential to an enterprise’s operations, the network perimeter, was previously the focus of network architects’ security plans. People inside the boundary were thought to be dependable and non-threats. They faced minimal limitations on their access to information as a result.

The trust presumption has been under scrutiny recently due to high-profile breaches. For starters, insiders can cause breaches, mostly unintentionally but occasionally on purpose. Additionally, when threats breach the perimeter, they have unrestricted access to almost any data, application, asset, or service by moving laterally throughout the network (DAAS). A complete spectrum of valuable assets can be easily exfiltrated by attackers with nearly unrestricted access, frequently before the intrusion has even been noticed.

The Zero Trust Response

Assumed trust has inherent flaws, which is why many firms employ the Zero Trust approach. Zero Trust presupposes that no one is reliable by default, not even people currently within the network perimeter. The foundation of Zero Trust is the idea of a “protect surface” placed around a company’s most important and valuable DAAS. The protective surface of the condensed network perimeter is times smaller than the attack surface because it only comprises the components necessary for business activities.

Network segmentation enters the picture in this situation. Network designers can effectively create a second layer of security by using segmentation to create a tiny boundary around the secured surface. Virtual firewalls can sometimes automate security provisioning to make segmenting operations easier. Regardless of how it is done, only authorized users are allowed control of assets within the protected surface, while everyone else is by default prohibited.

For hackers, segmentation spells terrible news since, except in the times of assumed faith, breaching the perimeter is no longer sufficient to obtain access to sensitive data. Physical and virtual micro perimeter stop threats from migrating laterally inside the network, effectively invalidating a large portion of the labor that went into causing the initial breach.

Network Segmentation Advantages

Network segmentation gives each sector of the network its security services, giving the user greater access to network traffic, enhancing network performance, and enhancing security posture.

To start, enhanced security. As we all know, security is a team effort, with each member being accountable for the other members. There is always a broad attack surface in a big flat network. The segregation of network traffic among smaller sub-networks created whenever a large network is divided into smaller ones limits the attack surface and prevents lateral displacement. Network segments thus stop attackers from traveling laterally within the network if the network perimeter is broken.

Segmentation also offers a logical means of isolating an active assault before it spreads throughout the network. As an illustration, segmentation ensures that malware in one section does not harm systems in another. The attack surface is minimized to the bare minimum by breaking an attack into parts.

Let’s move on to discussing performance. By removing unneeded traffic from a segment, segmentation lowers network congestion and boosts network performance. Medical equipment, for instance, can be separated from a hospital’s visiting network so that online browsing by visitors has no impact on the equipment. By segmenting the network, we may reduce the number of hosts per subnetwork, lower the amount of local traffic generated by each subnetwork, and only allow the external traffic specifically intended for the subnetwork.

How does network segmentation work?

Network segmentation divides a massive group into numerous independent parts, some of which can have different security needs and rules. The same confidence level is maintained for these segments’ holdings of the particular applications or endpoint kinds.

Network segmentation can be done in several different ways. We’ll examine perimeter-based segmentation that uses VLANs, followed by segmentation that uses network virtualization to achieve deeper network segmentation.

Perimeter-based segmentation

Perimeter-based segmentation divides the world into internal and exterior areas based on what can be trusted. Anything outside the network segment cannot be trusted. Since internal resources often run across a flat network with limited internal network segmentation, there aren’t many limits. At fixed network points, filtering and segmentation take place.

To enhance network performance, VLANs were initially created to separate broadcast domains. Although they were never intended to be a security tool, VLANs have changed over time to be utilized as one. The issue with VLANs is that they lack intra-VLAN filtering and have highly open access levels.

Furthermore, a policy is required to switch between segments. A policy allows you to control traffic flow by limiting it depending on the traffic’s kind, source, and destination or by stopping it from moving from one segment to another.

A typical tool for segmenting networks based on perimeters is a network firewall. It was initially used to regulate the north-south transfer of network activity while allowing every communication inside a segment.

Network Virtualization

Many firms maintain network zones with specialized tasks that necessitate segmentation at various network points. The endpoints that the network must enable have expanded to encompass a variety of endpoint kinds, each with a different level of trust.

Perimeter-based segmentation is therefore no longer adequate. The perimeter is now hazy with no distinct lines of demarcation because of developments like cloud computing, BYOD, and mobile. To improve security and network speed, we now need segmentation that is deeper within the network. Moreover, additional network segmentation is required due to the east-west traffic conditions of today. Network virtualization can be useful in this situation since it advances segmentation.

In its most basic form, network virtualization is the delivery of network and security services separate from the physical infrastructure. Network virtualization is crucial in promoting effective network segmentation by allowing network segmentation throughout the whole network, not only at the perimeter. In practice, the perimeter-based segmentation we were accustomed to has been virtualized and spread, along with flexible, granular security settings, to every network component.

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