Next Generation Firewalls: Complete NGFW Guide and Evaluation

A firewall is a device or software that monitors network traffic and applies a set of rules to determine which traffic will be allowed to connect to an organization’s devices and networks and which traffic will be blocked.

Next-generation firewalls (NGFWs) represent a significant advancement over traditional firewalls, providing deeper network traffic inspection, behavior-based analysis to identify suspicious activity and up-to-date threat intelligence to detect threats more quickly.

These advanced capabilities augment the fundamental protections provided by traditional firewalls, such as inspecting the data packets associated with incoming and outgoing network traffic to assess their safety and trustworthiness.

Data packets contain information such as the source and destination of the traffic and the payload (or content). For example, a firewall would block traffic originating from an IP address known to be malicious or following a suspicious pattern.

Traditional and NGFWs may be hardware or software, allowing organizations to select the most appropriate solution for their environment. Organizations with workloads predominantly in the cloud will gain certain advantages from cloud-native firewalls, which are designed for cloud environments and integrate easily with cloud tools. Organizations can also choose from an array of firewall features, functionalities and capacities.

Next-generation solutions offer the most advanced cybersecurity protection, but not every “advanced firewall” should be considered an NGFW. Gartner defines NGFWs as “deep-packet inspection firewalls that move beyond port/protocol inspection and blocking to add application-level inspection and intrusion prevention and bring intelligence from outside the firewall.”

Deep-packet inspection, or “packet sniffing,” means that firewalls analyze the contents of data packets rather than just the packet headers. This robust analysis, combined with machine learning and other advanced threat detection methods, makes NGFWs better equipped to defend against emerging security threats.

Although firewalls have been in use for a couple of decades, several factors have spurred a need for NGFWs’ more robust protection. Cyberthreats have become more sophisticated, efficient and frequent. Cybercriminals continuously refine their methods and devise new strategies, including the use of tools such as artificial intelligence. Accordingly, organizations’ firewall defenses must be able to adapt to new threat intelligence — one of the key capabilities that NGFWs provide.

In addition, modern networks are more complex than they used to be, making them harder to defend. Networks handle increasing numbers of devices and applications and support multiple types of traffic, including remote users. Advanced firewalls are better able to secure these disparate connectivity needs because they offer increased visibility, granular controls and dynamic threat monitoring.

Finally, NGFWs have become crucial because network security and visibility are indispensable for business continuity and disaster recovery. Organizations need secure, sustainable network performance, and NGFWs provide the protection to enable it.

Some organizations deploy next-generation solutions as part of a focused networking or cybersecurity update. Others deploy NGFWs as part of an infrastructure modernization initiative designed to enhance all aspects of the foundational infrastructure.

Traditional firewalls perform several key functions that establish a strong foundation for network security. These generally include packet filtering, stateful inspection (the use of contextual information to identify malicious traffic), network traffic logging and monitoring, access control management, and network address translation (modifying internal IP addresses to increase security and efficiency).

At the same time, traditional firewalls have limitations, especially in complex enterprise environments. Traditional network traffic inspections are more superficial than NGFWs’ deep-packet inspections, which makes them less able to distinguish between legitimate and malicious traffic.

Cybercriminals can circumvent traditional firewalls — for example, by hiding attacks within network traffic or at the application layer. Criminals may also disguise malicious traffic to appear legitimate during a cursory inspection and use encryption to obscure malicious payloads. Traditional firewalls may not detect these types of attacks.

In addition, traditional firewalls lack real-time threat intelligence, which makes them less effective at stopping zero-day threats. In the modern security landscape, cyberthreats aren’t static; they continually evolve. That means cybersecurity must be equally dynamic. NGFWs provide the behavioral analysis, machine learning and intelligence to accomplish that, while traditional firewalls do not.

NGFWs keep networks safe in two ways: preventing malicious traffic from entering the network and detecting malware that manages to slip past first-line defenses.

One of the core features of an NGFW is an intrusion prevention system, or IPS. As HPE explains, an IPS continuously monitors network traffic and takes proactive, automatic steps to respond to potential threats, such as reconfiguring the firewall on the fly or isolating network segments in real time to prevent malware from spreading from one area to another.

IPS, network segmentation and other functionalities, in combination with up-to-date threat intelligence, enable NGFWs to quickly prevent, detect and contain threats. To extend these protections across users, devices and critical environments, explore our broader network security solutions for operational technology, Internet of Things and hybrid architectures.

Modern networks are increasingly encrypted, which means NGFWs must evaluate traffic that traditional firewalls cannot meaningfully inspect. An effective NGFW strategy balances security, performance and privacy requirements.

Encrypted traffic inspection becomes especially important when dealing with threats hidden within TLS sessions, but not all traffic should — or legally can — be decrypted. Organizations should define clear policies around decryption, including exceptions for sensitive applications (HR, healthcare, financial tools); certificate‑pinned traffic that cannot be inspected; and considerations related to TLS 1.3, which encrypts more of the handshake and relies heavily on perfect forward secrecy.

Because decryption introduces additional processing requirements, teams should also evaluate throughput impact, the percentage of traffic expected to be decrypted, and whether dedicated hardware acceleration is needed. A well‑configured NGFW allows organizations to maintain visibility into encrypted attacks without compromising user privacy or degrading performance.

Modern NGFWs incorporate a suite of integrated capabilities designed to provide deeper visibility, stronger threat detection and more adaptive security across complex, hybrid environments. While specific implementations vary by vendor, most enterprise‑class NGFWs share several core feature sets that significantly enhance network protection.

Advanced threat detection is a foundational capability of NGFWs, enabling dynamic defenses that adapt to new and sophisticated attacks. These systems combine multiple detection techniques — including machine learning, behavioral analysis, heuristic evaluation and signature‑based analytics — to identify suspicious patterns that traditional firewalls often miss.

This layered, adaptive approach is essential for detecting zero‑day exploits, advanced persistent threats and increasingly evasive malware campaigns. By correlating activity across users, devices and applications, NGFWs can identify and contain threats early in the attack lifecycle.

Modern NGFWs incorporate robust URL filtering engines that evaluate both known and newly discovered websites. They leverage real‑time intelligence, content categorization and dynamic analysis to block access to malicious or inappropriate domains, prevent drive‑by attacks and enforce acceptable‑use policies.

This capability helps organizations reduce phishing risk, curb access to untrusted resources and create a safer browsing experience across the enterprise.

DNS infrastructure is a frequent target for attackers, who may use it for command‑and‑control channels, domain hijacking, spoofing or redirection attacks. NGFWs enhance DNS security by monitoring DNS queries and responses for anomalies, detecting malicious domains, applying reputation data, and enforcing policies that prevent devices from communicating with known or suspected threat infrastructure.

By intercepting threats at the DNS layer, NGFWs stop many attacks before they reach applications or endpoints.

Although NGFWs are primarily network‑focused, many incorporate endpoint‑aware logic to strengthen identity, device posture and traffic validation.

These capabilities may include:

• Monitoring endpoint behavior and traffic patterns
• Enforcing segmentation based on device type or role
• Automatically isolating devices that exhibit suspicious or noncompliant activity
• Identifying outdated software, misconfigurations or insecure device states

Endpoint‑informed rules help prevent lateral movement and reduce the risk of a single compromised device affecting broader network assets.

One of the defining advantages of NGFWs is their ability to analyze traffic at the application and user level — not just by port or protocol. This provides far deeper context and enables more granular, business‑aligned policy controls.

With application and user visibility, NGFWs can:

• Identify specific applications in use, even when they share ports
• Enforce policy based on user identity rather than just IP address
• Distinguish sanctioned applications from shadow IT
• Detect high‑risk or unusual behavior tied to individual users or user groups
• Support role‑based access and zero-trust policies

This level of visibility is critical for modern environments, where applications may be cloud‑based, encrypted or dynamically shifting.

As organizations rely more heavily on Software as a Service platforms and distributed cloud workloads, NGFWs increasingly integrate or interoperate with cloud access security broker capabilities. These integrations help extend visibility and control into environments that traditional on‑premises security tools cannot fully monitor.

Integrated CASB‑aligned capabilities typically include:

• Monitoring and analyzing SaaS application usage
• Enforcing policy across cloud and hybrid environments
• Identifying risky or unsanctioned cloud services
• Applying consistent DLP, access and compliance controls
• Inspecting cloud‑bound traffic for anomalies or threats

This combination ensures that security policies remain consistent — from on‑premises infrastructure to remote users and cloud applications — without creating blind spots.

Organizations that want to extend firewall protection into cloud environments must verify that their NGFW supports virtualized deployment in Amazon Web Services (AWS), Azure or other public cloud platforms. Cloud‑ready NGFWs should integrate with cloud routing constructs, scale with demand and provide the same inspection, control and visibility expected in on‑premises deployments.

This is especially crucial for SaaS applications and hybrid architectures, where traditional, perimeter‑based controls offer limited protection.

As organizations expand into cloud and hybrid environments, firewalls must adapt to new traffic patterns, application architectures, and connectivity models. NGFW capabilities vary significantly between vendors when deployed in AWS, Azure or hybrid data centers, so buyers should understand the core differences.

At a minimum, cloud‑ready NGFWs should integrate with cloud networking constructs (such as VPCs, VNets, Transit Gateways and virtual routing), provide consistent policy enforcement across on‑premises and cloud workloads, and offer support for emerging cloud security controls such as CASB and inline SaaS monitoring. In cloud environments, NGFWs often support inline inspection, centralized hub‑and‑spoke inspection, or virtual firewall deployments, each with trade-offs related to latency, costs, and operational complexity.

Organizations should look for NGFW solutions that maintain policy consistency, scale elastically with demand and integrate with existing cloud governance frameworks. This ensures that network‑based visibility and protection extend seamlessly across hybrid environments.

Because NGFWs generate high‑value telemetry, organizations benefit most when firewalls are consistently tuned and monitored. Many modern NGFW platforms incorporate AIOps or automated best‑practice engines that provide insights into configuration drift, performance bottlenecks and potential policy gaps.

Teams should routinely review telemetry such as:

• Rule hit and miss patterns to identify overly permissive or unused rules
• SSL/TLS error rates that may indicate misconfigurations or decryption issues
• Connections per second (CPS) spikes and session table utilization
• Anomaly detection alerts for unusual user, device or application behavior
• Changes to application usage patterns that may require new controls

These insights help security teams maintain a strong security posture, reduce misconfiguration risk and ensure policy sets evolve as applications, users and workloads change. Even without full AIOps adoption, a structured telemetry review process significantly enhances NGFW effectiveness.

Most organizations take a layered approach to cybersecurity, orchestrating multiple solutions into a well-coordinated environment. Here are some tools that share similarities with NGFWs:

A NGFW is a foundational security control, but it is not a replacement for every type of security technology. Choosing the right tool depends on the threat model and application architecture.

Use an NGFW when:

• You need deep-packet inspection for network traffic
• You require intrusion prevention, URL filtering, DNS security or user‑based policies
• You need visibility and enforcement across multiple layers of network activity

Use a WAF when:

• You must protect web applications, application programming interfaces or mobile apps
• The goal is to block OWASP Top 10 threats or malicious HTTPS requests
• Application‑layer logic and payload inspection are required

Use FWaaS when:

• You want cloud‑delivered firewall protections across distributed users
• You need simplified deployment without hardware
• You’re integrating into an SSE or SASE architecture

Most enterprises use a combination of these tools to create a layered defense strategy tailored to network, web application and remote user needs.

Selecting the right NGFW requires evaluating how well the solution delivers advanced security, operational efficiency and consistent protection across on‑premises, cloud and hybrid environments. While specific capabilities vary, enterprise-grade NGFWs should excel in several key areas.

An NGFW should combine multiple security engines to detect and stop threats across the full attack lifecycle.

Core capabilities include:

• Intrusion prevention with deep-packet inspection
• URL filtering and web threat protection
• DNS security and domain reputation analysis
• Sandboxing to isolate and analyze suspicious files
• Machine learning and behavioral analytics to detect unknown or evolving threats
• Continuous threat intelligence updates to stay aligned with emerging attack patterns

These features work together to prevent attacks before they spread and to identify sophisticated threats that bypass traditional controls.

Visibility is the foundation of effective security. An NGFW should provide:

• Insight into network activity across users, devices, applications and hosts
• Monitoring of east‑west and north‑south traffic patterns
• Awareness of active applications, websites, file transfers and virtual machine communications
• Contextual data that enriches alerts with user identity, device posture and application behavior

This level of visibility enables more informed decisions, reduces blind spots and supports zero-trust strategies.

Speed matters. Modern NGFWs should be capable of:

• Detecting threats in seconds
• Identifying potential breaches within minutes or hours
• Prioritizing alerts based on severity and business context
• Translating raw network events into actionable insights security teams can immediately respond to

Effective NGFWs not only identify threats but also streamline response workflows through intelligent event correlation and clear, interpretable dashboards.

Organizations should choose an NGFW that adapts to their environment rather than forcing architectural constraints. Look for:

• Options for centralized or distributed management
• Support for appliances, virtual firewalls and cloud‑native deployments
• Scalability across different throughput requirements, ensuring performance even with decryption and deep inspection enabled
• High‑availability and clustering options for resilience

This flexibility ensures the NGFW aligns with current needs and can evolve as the organization grows or shifts.

NGFWs must operate as part of a cohesive security ecosystem — not in isolation. Essential integration points include:

• Security information and event management (SIEM) and security orchestration, automation and response (SOAR) platforms for centralized analysis and automation
• Endpoint security tools, enabling coordinated response
• Identity and access management systems, allowing identity‑based enforcement
• Email and cloud security services, ensuring consistent policy application
• Threat intelligence feeds for real‑time awareness

Strong integration capabilities ensure consistent enforcement and reduce operational complexity across hybrid and multicloud environments.

Evaluating NGFW capabilities is an essential first step, but getting value from these features requires thoughtful planning and deployment. With the right preparation, organizations can maximize performance, ensure policy accuracy and avoid common implementation pitfalls.

Deploying an NGFW in an existing enterprise environment requires careful preparation. A structured approach minimizes user disruption and ensures that advanced capabilities like deep‑packet inspection and behavioral analysis can be activated safely.

A simplified migration framework includes:

1. Discovery and rule cleanup: Analyze existing policies, remove duplicative or unused rules and document dependencies.
2. Object and policy normalization: Standardize naming conventions, network objects and application categories to simplify management.
3. Simulation and visibility mode: Allow the NGFW to observe traffic patterns before enforcing new policies.
4. Staged enforcement: Gradually introduce intrusion prevention, URL filtering and decryption policies to minimize false positives.
5. Controlled cutover: Migrate traffic during a scheduled maintenance window with rollback options.
6. Day‑one tuning and monitoring: Adjust policies based on real‑world traffic and early telemetry.

This process helps organizations avoid disruption and ensures that new NGFW capabilities are deployed in a secure and sustainable manner.

As organizations refine policies and build long‑term operational maturity, investing in security and firewall training can help teams avoid misconfigurations, strengthen incident response readiness and ensure new NGFW capabilities are fully utilized.

To ensure the chosen NGFW aligns with long‑term security and operational requirements, organizations should verify that solutions offer:

• Advanced threat prevention: DPI, IPS, sandboxing and behavioral analysis
• Robust encrypted traffic inspection: TLS 1.3 readiness, strong privacy controls
• Cloud compatibility: Seamless deployment across AWS, Azure, hybrid networks
• Application, user and device awareness: Granular visibility into modern workloads
• Scalability and performance: Throughput appropriate for decryption and growth
• AIOps or best‑practice guidance: Tools that reduce configuration errors
• Centralized management: Unified policy management across sites and environments
• Integration with security ecosystem: Compatibility with SIEM, endpoint security and identity platforms
• Operational transparency: Clear reporting, dashboards and alert prioritization

This checklist helps guide internal discussions and vendor evaluations, ensuring the NGFW delivers measurable, long‑term value.

Successful deployment of an NGFW in an enterprise architecture starts by selecting the right solution for the organization’s needs, goals and challenges.

IT and cybersecurity teams should assess the existing security environment to answer questions such as:

• What are its capabilities and limitations?
• Which NGFW features and functionalities are priorities?
• How can an NGFW best complement existing solutions?
• What are the integration capabilities of existing solutions?
• Based on current and projected network traffic, what is the necessary capacity for an NGFW?

Developing a clear, detailed picture of the existing environment is necessary to achieve optimal results from an NGFW investment. For example, IT and cybersecurity teams must understand the factors that influence NGFW capacity to ensure the firewall delivers advanced protection without compromising network performance. The same features that make NGFWs so powerful — such as deep-packet inspection and machine learning-enhanced analysis — require sufficient throughput.

NGFWs also vary in specifications such as connections per second and maximum supported sessions. While cloud-based NGFWs offer the flexibility to scale up capacity as network traffic increases, hardware firewalls are limited in this regard.

Firewall configuration is another critical step in the deployment process. Configurations determine how the firewall will integrate with network infrastructure, handle network traffic and apply policies for cybersecurity, access control, endpoint protection and other areas. For example, some NGFWs allow users to define policies based on defined user groups (instead of IP addresses). Configurations play a crucial role in a firewall’s effectiveness and capacity, so it’s essential to get them right.

Once a firewall is deployed, organizations should keep software current by maintaining patches and updates. This is especially important for NGFWs, which leverage threat intelligence to detect zero-day attacks and other emerging threats.

Because NGFWs provide deep visibility into network traffic, they are a rich source of data and insight for IT and cybersecurity teams. Staffers should review firewall activity routinely to understand the patterns behind malicious activity, as well as the organization’s overall network traffic and trends. These insights help teams refine firewall settings to better align with actual application usage, close security gaps, and minimize misconfigurations that could inadvertently block legitimate traffic or allow suspicious traffic to slip through.

Ongoing monitoring also ensures that security policies and firewall configurations are functioning as intended, network bottlenecks are minimized and best practices are maintained.

While NGFWs are powerful, they aren’t entirely a “set it and forget” solution. Changes in the threat landscape, network traffic and other areas of the IT infrastructure can affect firewall performance, and teams may need to adjust settings and configurations accordingly. Organizations that lack the internal resources to manage these processes effectively or that want their cybersecurity teams to focus elsewhere may use managed security services.

Expert partners can provide ongoing firewall monitoring and optimization, ease integration challenges and ultimately help to increase ROI from a business perspective.