How to Implement Network Segmentation: Best Practices and Tips

With cybersecurity threats on the rise, network segmentation is one of the best network security practices out there. Compartmentalizing a network limits the flow of traffic, ensuring only legitimate queries and secure data are allowed to pass through. Segmentation also limits a network’s exposure, making each segment easier to manage and secure. 

Network segmentation is a rising network security goal: 96% of surveyed organizations use segmentation for IT security.  However, not all businesses are able to implement it effectively. Segmentation is only effective if properly implemented throughout the business network. 

Tips and Best Practices

Implementing network segmentation allows for varying security protocols to be used for different sections of the network. It can be based on differing security protocols, without limiting employee functionality. As a cybersecurity tool, it contains hacking attempts to a single compartment, preventing it from jeopardizing the entire network. Some of the best practices that should be applied with network segmentation include:

Network mapping

Network mapping is exactly what it sounds like- understanding and illustrating the various components of your network. It shows how they relate to one another and who requires what components, and for what purpose. A network diagram should help you map out how each element of your network connects together, making segmentation simpler. 

The key to network mapping is to ensure each segment is capable of functioning independently on a regular basis. Attempting to segment your network without first defining or mapping it is likely to result in overlapping sections that are ineffective in limiting unauthorized access. With a visual map to refer to, it can be easier to determine what a network segmentation would look like.

Network mapping is a useful practice down the road as well, to help monitor the segmentation strategy, identify areas of vulnerability, and implement changes or new strategies as needed. Businesses tend to evolve and grow, and the changing network architecture would need to be mapped to ensure the segmentation strategy was still effective, or if a new one was needed.  

Identifying critical assets

Along with network mapping, understanding, and evaluating the organization’s critical assets is essential for successful network segmentation. Such assets, for example, databases and financial data, include those components that are required by the business to maintain its operations and function effectively. These assets can most constructively be grouped based on the data sensitivity level, which would dictate the security protocol those assets require.

High-sensitivity assets, for example, may be grouped together when segmenting the network and may be subject to a more comprehensive security protocol. Similarly, lower-sensitivity assets may have fewer restrictions on them with a wider access pool. 

Once critical assets have been identified and similar-level assets are grouped together, it gets simpler to know what kind of network segmentation and security policies each segment would require. It is also useful to know for the future when the network undergoes changes, and systems or segments need to be updated.

Defining policies

The policies you implement during network segmentation need to fulfill a simple, two-point criteria. They must be sufficiently comprehensive to ensure that each segment of your network is protected from internal and external threats as well as possible, but should not be so stringent that it hinders business operations or functionality.  

The policies that you bring into effect, therefore, need to be defined before they are utilized. Use your network map to identify relations between various sections of the network, and highlight critical assets on the map.  

In practice, access restrictions, the protocol for external communication, and security systems should be defined beforehand. This is to ensure they will be sufficient in ensuring the safety of the network. 

Limiting third-party access

The first goal of network segmentation is to implement security within the organization’s access points. Once internal network security has been configured, businesses should turn their focus to third-party access, which can be more easily monitored and controlled in a segmented network. Third-party access includes vendors or contracted providers who do not need complete access to a business’s network to do their jobs. 

The best way to limit such access is to create segments and uniquely-defined controls for each of these third parties. Such controls would depend on the function of the third party within the organization and should restrict any access that is not strictly necessary. 

Open remote access to third parties increases the vulnerability of a network and makes it more susceptible to attack. The network map should help determine which path third parties would require, and what restrictions must necessarily be implemented in developing policies for access. 

Avoiding Common Pitfalls in Network Segmentation

When implementing network segmentation, it is easy to fall into security traps that leave the network vulnerable. Some of these pitfalls that organizations should look out for include:

Lack of planning

The planning process before the actual implementation serves a key purpose- to ensure you have considered every network vulnerability and segmentation need before putting it into effect. It is necessary to plot how each policy would influence business functionality and security, and when and where changes may be needed. 

Without proper planning, organizations may end up over or underestimating their needs. As a result, the implemented strategies would not serve business purposes- at best they would be a hindrance, and at worst, they can open up the organization to external and internal attacks.

Over- or under-segmentation

While organizations sometimes believe that creating more segments improves security, it actually creates functionality problems for the business. Over-segmentation can restrict the flow of traffic, and bring workflow to a halt while employees are forced to go through multiple access points just to do their jobs. 

Similarly, under-segmentation means there is a great overlap between high-sensitivity and low-sensitivity segments, meaning the lax security on the latter can be exploited. The key is to strike a balance between the two situations, that keep the business running without exposing it to risk.

Final Thoughts

Network segmentation allows for an organization’s network to be protected by breaking it up into self-contained, secure compartments. While an important security tool, it can be made more effective by implementing best practices that can ensure network security. Carrying out sufficient planning, for example, by network mapping, identifying organization-critical assets, and defining policies before implementation ensures the effectiveness of this strategy.

Organizations should also be aware of mistakes they can make along the way, and how to avoid them. In the planning and implementation process, the key is to strike a balance between business security and functionality, so that neither is compromised and each can be safely maintained.