Network Security: Fundamentals, Threats and Best Practices

For years, network security was largely built around a simple idea: keep threats outside and trusted users and systems inside. That model becomes harder to maintain when employees work from anywhere, applications and workloads span multiple cloud environments, and third parties, IoT devices, and OT systems connect to the same business infrastructure.

The challenge is no longer limited to stopping unauthorized traffic at the network perimeter. Security teams also need to understand who is accessing a resource, whether the device can be trusted, what systems that access can reach, and whether an attacker who gets in can move further across the environment.

This has turned network security into a broader discipline that brings together firewalls, access controls, network segmentation, threat detection, continuous monitoring, and Zero Trust approaches. The goal is not simply to block attacks at the edge, but to maintain visibility and control across an increasingly distributed network.

This guide explores what network security means today, the solutions and threats organizations need to understand, how Zero Trust and SASE are changing network security architecture, and the best practices for building a more resilient network security strategy in 2026.

Key takeaways

Network security goes beyond the perimeter. Cloud environments, remote users, third-party connections, and IoT/OT systems have expanded the network organizations need to secure.
No single security control is enough. Firewalls, access controls, segmentation, monitoring, and threat detection need to work together to address different attack paths.
Network security needs to be continuously monitored. Detecting unusual activity early can help organizations contain threats before attackers move further through the environment.
Zero Trust changes how access is managed. Instead of trusting users or devices based on network location, access is verified and limited according to identity, device status, and required permissions.
Segmentation can limit the impact of a breach. Separating critical systems and workloads makes it harder for attackers to move laterally after gaining initial access.
Security architecture must evolve with the network. SASE, ZTNA, cloud security, and integrated monitoring are becoming increasingly relevant as organizations move away from traditional perimeter-based environments.
Compliance and security should be managed together. Network controls should support both day-to-day security operations and the specific requirements that apply to the organization.

What is network security?

Network security is the practice of protecting a network from unauthorized access and activity. It combines security technologies, processes, and policies to control access, protect data, and keep connected systems available.

A useful way to understand network security is through the CIA triad:

Confidentiality: Prevent unauthorized people from accessing information.
Integrity: Prevent information from being changed without authorization.
Availability: Keep systems and data accessible when they are needed.

A stolen database is a confidentiality problem because unauthorized users gained access to the data. An attacker changing records creates an integrity problem, while a DDoS attack that takes a service offline affects availability.

The scope of network security has also expanded beyond the traditional corporate network. Remote employees, cloud workloads, third-party connections, IoT devices, and OT systems can all connect to business environments, giving security teams more access points to monitor and control.

8 types of network security solutions

A network can be attacked at several points, from an exposed internet-facing service to a compromised employee device or an unauthorized connection to a critical system. Different security controls address different parts of this problem, so organizations typically build network security as a combination of traffic filtering, access control, threat detection, data protection, and containment.

The right combination depends on the organization’s environment. A business with remote employees may prioritize secure remote access and Zero Trust, while an organization with sensitive databases or OT systems may place greater emphasis on segmentation and access control.

The following 8 solutions form common layers of an enterprise network security architecture.

8 types of network security solutions

1. Next-generation firewall (NGFW)

A next-generation firewall sits at key points in the network and controls which traffic is allowed to pass between networks, systems, and the internet. Unlike traditional firewalls that primarily filter traffic based on IP addresses and ports, NGFWs can identify applications, inspect traffic for threats, and apply more detailed security policies.

This makes the firewall useful for controlling both what can connect and what that connection is allowed to do.

Example: An organization can allow employees to access approved business applications while blocking traffic from a known malicious destination or an unauthorized application.

2. Intrusion detection and prevention (IDS/IPS)

IDS and IPS are designed to identify network activity that may indicate an attack. An IDS monitors traffic and alerts security teams when it detects suspicious patterns, while an IPS can take action to block or stop the detected activity.

These controls add another layer beyond basic traffic filtering because they look for behavior associated with known attack techniques and suspicious network activity.

Example: If an attacker sends repeated exploit attempts toward a vulnerable server, an IPS can detect the malicious pattern and block the traffic before the attack succeeds.

3. VPN and secure remote access

Remote users need a secure way to connect to business resources without exposing sensitive traffic or services directly to the internet. A VPN creates an encrypted connection between the user or remote site and the organization’s network, helping protect data while it is being transmitted.

Traditional VPNs often provide broad network-level access once a user connects. For environments with many remote users and cloud applications, organizations may instead use more granular approaches such as Zero Trust Network Access (ZTNA).

Example: A remote employee can securely connect to internal resources through a VPN, while a ZTNA solution can limit that employee’s access to only the specific applications required for their role.

4. Zero Trust and SASE

Traditional network security often relied on a perimeter: users and devices inside the corporate network were generally considered more trustworthy than those outside it. Zero Trust takes a different approach by requiring access to be verified based on factors such as identity, device status, and the resource being requested.

SASE extends this model to distributed environments by combining networking with cloud-delivered security services such as ZTNA, secure web gateways, and cloud access security controls.

Example: Instead of giving a remote employee broad access after connecting to the corporate network, Zero Trust can verify the employee and device before allowing access only to the applications required for their role.

5. Network access control (NAC)

Network Access Control determines which devices are allowed to connect to a network and what level of access they should receive. Before granting access, NAC can check whether a device is known, authorized, and compliant with security requirements.

This is particularly useful when organizations have many different types of devices connecting to the same environment, including employee endpoints, contractors’ devices, IoT equipment, and other unmanaged systems.

Example: An employee’s laptop may receive normal network access, while an unknown device is denied access or placed into a restricted network until it can be verified.

6. Data loss prevention (DLP)

Network security is not only about stopping attackers from entering the environment. Organizations also need to prevent sensitive information from leaving through unauthorized channels.

DLP monitors the movement of sensitive data and can apply policies when information is being transferred through email, web traffic, cloud services, or other channels. Depending on the policy, it can alert security teams or block the transfer.

Example: If an employee attempts to upload a file containing sensitive customer information to an unauthorized external service, a DLP control can detect the data and prevent the transfer.

7. SIEM and XDR

Security teams need visibility into what is happening across the network to identify attacks that individual security controls may not detect on their own. SIEM collects and correlates logs from network devices, applications, endpoints, and other systems, while XDR connects security telemetry across areas such as network, endpoint, cloud, and identity.

The value comes from connecting these signals. An unusual network connection may not mean much on its own, but it becomes more significant when combined with a suspicious login and unusual activity on the affected device.

Example: A security team can correlate a suspicious login, an unusual network connection, and abnormal endpoint behavior to investigate whether an account or device has been compromised.

8. Network segmentation and micro-segmentation

Network segmentation divides an environment into separate security zones and controls the traffic allowed between them. The purpose is to prevent an attacker who compromises one system from freely reaching other parts of the network.

Micro-segmentation applies this principle at a more granular level, such as individual applications, workloads, or systems. This can be especially important for environments containing critical applications, sensitive data, or OT infrastructure.

Example: If an employee workstation is compromised, network segmentation can prevent the attacker from using that device to directly access a database server or critical OT system.

Top network security threats in 2026

Network threats are becoming more difficult to contain as attackers gain faster access to new techniques and organizations connect more systems to their networks. Cloud environments, third-party access, remote users, and IoT and OT devices have also expanded the number of paths that attackers can use.

The most important threats are not limited to attacks that break through the network perimeter. A compromised account, trusted vendor connection, or vulnerable connected device can give attackers a starting point inside the environment, making detection and containment just as important as prevention.

1. Ransomware and lateral movement

Ransomware attacks can cause more damage when attackers move from the initially compromised system to other parts of the network. Once inside, attackers may attempt to escalate privileges, access critical systems, and disrupt multiple services before deploying ransomware.