Technical Review by
Laura Iannini
Network firewalls inspect and control traffic based on security policies — blocking unauthorized access, filtering threats, and segmenting networks to limit lateral movement after a breach. The firewall remains a foundational control, but inspection depth and performance under real traffic loads vary significantly across vendors. We reviewed the top platforms and found NordLayer Cloud Firewall, Aviatrix Cloud Network Security Platform, and Barracuda CloudGen Firewall to be the strongest on threat inspection capabilities and throughput under realistic conditions.
The network firewall market is crowded, and the specifications published by vendors often bear no relationship to real-world performance. A firewall rated for 100 Gbps throughput drops dramatically once you enable IPS, SSL inspection, application control, and malware detection simultaneously. You’re left choosing between advertised performance you can’t trust or building your own testing lab to validate claims.
Beyond raw performance, your choice depends on your deployment model. Branch offices have different requirements than data centers. Hybrid environments with mixed on-premises and cloud infrastructure need consistency across environments. Small teams need interfaces they can actually navigate. Enterprises need policy granularity and integration depth that smaller products don’t offer. Get it wrong, and you’re either undersized and struggling, or oversized and paying for features your team will never use.
We evaluated multiple network firewall solutions across performance under full security load, management interface usability, policy flexibility, cloud integration, and real-world deployment complexity. We focused on evaluating headline specifications against actual operational performance and whether the security depth vendors promise actually translates to threat prevention your team can rely on.
This guide gives you the framework to match the right firewall to your specific environment, whether that’s protecting branch offices, consolidating hybrid infrastructure, or building cloud-native security at scale.
We found that the top options here excel at different goals. Pick based on your team’s priorities.
NordLayer Cloud Firewall is a Firewall-as-a-Service (FWaaS) that protects private networks and cloud infrastructure without requiring on-premises hardware. We think it’s a strong option for small to mid-sized teams running hybrid cloud environments who need managed network security without dedicated firewall expertise. The zero-trust access model limits users to only the resources they need, which reduces the attack surface for distributed teams.
DNS filtering blocks malicious websites and inappropriate content at the network level, giving admins granular control over what users can reach. The cloud-based control panel handles policy management, and automatic updates keep protections current without manual intervention. Network segmentation, device posture monitoring, and threat protection layer on top of the core firewall functionality. Deployment is straightforward with no hardware to manage, and the admin dashboard is clean enough that non-networking staff can navigate it without specialized training.
Customers praise the simplicity of switching between VPN connections and the reliable performance under multi-user load. Remote access works well for distributed teams connecting to internal tools without public internet exposure. Something to be aware of is that advanced configuration options can feel restrictive; split tunneling requires support requests rather than self-service setup. The Team Admin role has limited permissions, and MFA resets require deleting and recreating users.
If your team needs managed cloud firewall protection with zero-trust access controls and you lack dedicated firewall staff, NordLayer fits that gap well. Pricing starts at $8 per user per month for the Lite plan, with cloud firewall features available on the Premium tier at $14 per user per month. We think it works best for small to mid-sized teams prioritizing simplicity over deep customization, which is a fair trade-off at this price point.
Aviatrix delivers a distributed cloud firewall built for enterprises running multi-cloud environments across AWS, Azure, Google Cloud, and Oracle Cloud. We were impressed by the platform’s focus on east-west and egress traffic protection with zero-trust policy enforcement at scale. It sits firmly in the enterprise tier of cloud network security tools, and we think it’s best suited for organizations with dedicated cloud networking teams.
The distributed firewall creates a virtual perimeter across cloud providers, enforcing consistent security policies regardless of where workloads live. Identity-based SmartGroups let you define access rules tied to application context rather than just IP addresses. End-to-end encryption handles speeds up to 100 Gbps, which held up well under heavy traffic loads. The CoPilot tool provides real-time flow visibility and helps pinpoint network anomalies during multi-cloud operations; this is a strong differentiator. Network Detection and Response adds another layer by identifying threats that traditional firewalling misses.
Customers praise the consistent experience across all four major cloud providers and the responsive engineering support. Small teams running complex environments highlight that the platform reduces their dependency on large networking headcounts. Something to be aware of is that gateway deployment is required in each VPC and subnet to get traffic flow intelligence and enforcement, which adds architectural overhead. The initial setup is complex, particularly around BGP and routing management.
If your organization runs workloads across multiple cloud providers and needs consistent firewall enforcement with deep traffic visibility, Aviatrix addresses that problem directly. The platform also recently introduced Zero Trust for AI Workloads, which lets IT teams secure AI agents and LLM proxies without application changes. We think it’s one of the strongest options in the multi-cloud firewall space for finance, healthcare, and technology enterprises.
Barracuda CloudGen Firewall is a unified security platform that protects on-premises and multi-cloud networks through IPS, URL filtering, antivirus, and application control. We think it’s a strong option for organizations with distributed environments spanning multiple offices, cloud providers, and remote users. The built-in SD-WAN component is a real differentiator; it connects distributed sites and cloud environments without requiring a separate networking solution.
The firewall combines advanced threat signatures, behavioral and heuristic analysis, static code analysis, and sandboxing into a single platform. Integration with Barracuda’s Advanced Threat Protection service adds continuous defense against emerging threats, backed by their global intelligence network. A single centralized management console handles the global rule base across all environments, which means one policy framework whether you’re running cloud workloads or on-prem infrastructure. Once the initial configuration is complete, the platform runs with minimal supervision.
Long-term customers praise the price-to-performance ratio and highlight vendor support as significantly above industry average. Organizations running hybrid environments for eight or more years report consistent satisfaction with centralized management. Something to be aware of is that configuration logic differs from other firewall vendors, so teams switching from another product should budget time for the transition. Diagnostic information and troubleshooting flows can feel less intuitive than some alternatives.
If your organization runs a hybrid environment with multiple offices and cloud providers, Barracuda CloudGen Firewall consolidates firewall and SD-WAN into one managed platform. We were impressed by the long-term stability customers report; the operational overhead stays low once your rules are in place. It’s well worth considering for mid-market and enterprise teams that value operational simplicity after initial setup.
Check Point Quantum is an AI-powered NGFW that provides security across endpoints, networks, cloud, data centers, and remote users. We were impressed by the SandBlast zero-day protection, which combines threat emulation and threat extraction to catch unknown threats before they reach the network. The platform scales from branch offices to large enterprise environments managed from a single unified console.
SandBlast zero-day protection is the standout capability. It uses over 50 AI engines and real-time global threat intelligence to achieve a 99.9% block rate against zero-day attacks. IPS, application control, URL filtering, and identity-based inspection layer on top for defense in depth. The unified policy management handles on-premises, cloud, and remote site policies from one console, which eliminates the fragmentation that comes with managing separate tools. The Quantum Spark hardware line offers plug-and-play deployment for branch and edge locations with SD-WAN integration.
Customers in defense and enterprise environments praise the strong branch office protection and ease of daily management. The plug-and-play setup for Quantum Spark appliances gets positive marks for reducing deployment time. Something to be aware of is that firmware updates on hardware appliances require manual intervention and can introduce glitches. Some users feel that real-time network monitoring capabilities are limited for certain deployment scenarios.
If your organization needs scalable NGFW protection across branch offices, cloud, and data centers with zero-day threat prevention, Check Point Quantum covers that ground well. The Quantum platform can now scale up to 1 Tbps throughput with Quantum Lightspeed models at ultra-low latency, which is good to see for organizations with growing traffic demands. We think it’s a strong fit for mid-market and enterprise security teams.
Cisco Secure Firewall 4200 Series is a high-performance NGFW built for large organizations that need scalable threat protection. The platform delivers up to 140 Gbps throughput with application visibility and IPS enabled, and the ability to stack up to 16 devices as a single logical unit means you can inspect over 1.5 Tbps of traffic. We think it’s one of the strongest options available for large security teams already invested in the Cisco ecosystem.
The series includes three models, the 4215, 4225, and 4245, all in a compact 1 RU form factor. Cisco Talos integration feeds continuously updated threat intelligence into the firewall, strengthening security against emerging attacks. Zero-trust policies automate access decisions, and unified policy management spans diverse environments so security teams write rules once and apply them consistently. The dashboard provides strong traffic visibility and gives security teams the context they need for fast decisions.
Customers rate the platform highly for advanced threat detection, reliable performance, and strong traffic visibility. The Cisco ecosystem integration gets consistent praise from organizations already running Cisco infrastructure. Something to be aware of is that the management interface can feel clunky, requiring multiple browser tabs for configuration views. CLI capabilities lag behind Cisco’s legacy ASA product line, which experienced firewall engineers may find limiting.
If your organization runs Cisco infrastructure and needs a firewall that scales to enterprise traffic volumes with deep threat intelligence, the 4200 Series fits that profile well. The Talos integration and stackable architecture are strong differentiators. With that said, teams without existing Cisco investment should weigh the ecosystem lock-in and management complexity against alternatives in this space.
Forcepoint NGFW is an enterprise firewall with built-in SD-WAN that supports a SASE architecture. We think it’s a strong fit for organizations managing distributed networks that need centralized policy control with high availability and granular customization. The built-in SD-WAN is the key differentiator; rather than layering SD-WAN on top of a separate firewall, Forcepoint packages both into a single solution.
Centralized management through the Secure Management Console handles policy configuration, automated updates, and network traffic insights across all locations. The platform supports Layer 3-4 and Layer 7 protection with options to stack in high availability configurations. Automated unified policy updates push changes across the environment without manual site-by-site work. VPN, intrusion prevention, and web filtering all run stable under high traffic loads, and the all-in-one licensing approach avoids the add-on fatigue common with other firewall vendors.
Long-term customers describe Forcepoint as a critical part of their security model and highlight reliable performance under heavy traffic. The SD-WAN integration and all-in-one licensing get consistent praise. Something to be aware of is that the user interface requires deep product knowledge and isn’t intuitive for new administrators. Initial setup and advanced configuration demand significant training investment.
If your organization manages distributed sites and needs firewall plus SD-WAN in a single platform without separate licensing, Forcepoint NGFW is well worth considering. The policy granularity is where it earns its reputation; the level of customization available across protection layers means you can tailor the firewall to specific business requirements. We think it’s best suited for teams with the resources to invest in training upfront.
Fortinet FortiGate is an NGFW built on custom ASIC architecture that delivers hardware-accelerated threat protection across branch offices, campuses, data centers, and cloud environments. We were impressed by the performance consistency; SSL deep inspection, IPS, and advanced threat protection run at wire speed without choking bandwidth-heavy applications like VoIP or Teams calls. FortiGate is widely regarded as the market benchmark in this space, and we think that reputation is earned.
Custom Security Processing Units (SPUs) are what set FortiGate apart from software-only firewalls. The latest fifth-generation ASIC, FortiSP5, delivers 17x faster firewall performance, 32x faster encryption, and 88% less power consumption than standard CPUs. FortiGuard global intelligence feeds AI and ML-driven detection for both known and unknown threats. FortiOS is consistent across the entire ecosystem; CLI commands are universal whether you’re managing a small branch unit or dozens of appliances. SD-WAN, switching, wireless, and 5G capabilities converge into the firewall platform.
Customers praise the GUI usability, CLI depth, and real-time visibility that simplifies day-to-day administration. Hardware acceleration under heavy load gets consistent positive feedback, and TAC support earns marks for knowledgeable assistance on complex cases. Something to be aware of is that firmware upgrades can introduce unpredictable changes, and some versions contain feature-breaking bugs. The knowledge base is inconsistent, which makes self-service troubleshooting harder than it should be.
If your organization needs a firewall that scales from branch to data center with hardware-accelerated performance and deep networking integration, FortiGate is well worth considering. The converged SD-WAN, switching, wireless, and 5G capabilities reduce the need for separate networking products. We’d recommend evaluating renewal terms and partner relationships carefully before signing; on the technical side, the platform delivers across environments.
Juniper SRX Series is a zone-based firewall platform that scales from 1.9 Gbps to 1.44 Tbps across physical, virtual, and containerized form factors. Now part of HPE following the acquisition completed in July 2025, the SRX series continues to be actively developed with new models like the SRX400 for branch networks. We think it’s one of the strongest options for organizations with Junos experience that need proven long-term stability.
Junos OS is the foundation, and customers with networking backgrounds will recognize its strengths immediately. The zone-based firewall model provides clean traffic segmentation, and the commit-confirm workflow lets you verify changes before they go live; that safety net matters when managing production firewalls. IPS, content security, and advanced security services run across all form factors. EVPN-VXLAN support adds fabric-aware security for modern data center architectures. Juniper achieved a 99.7% exploit block rate with zero false positives in independent testing, which is very strong.
Customers rate the SRX series highly for stability, performance, and the strength of Junos OS. The zone-based architecture gets praise as one of the strongest in the market. Organizations running SRX for eight or more years report stable performance with minimal disruption. Something to be aware of is that the JWeb management interface has persistent bugs and can feel slow. In-depth traffic visibility requires Juniper Security Director beyond the built-in GUI.
If your team has Junos experience and needs a firewall that scales from branch to data center with proven long-term stability, the SRX series is a natural fit. The GigaOm 2026 Enterprise Firewalls report named it a leader and outperformer, with only 4 of 17 vendors achieving that distinction. Teams without Juniper experience should factor in the learning curve around Junos and the GUI limitations.
Palo Alto Networks VM-Series is a virtual NGFW that brings the same security capabilities as physical Palo Alto appliances into virtualized and cloud environments. We were impressed by the full feature parity; App-ID, User-ID, and Threat Prevention all carry over without compromise. The 2026 SecureIQLab report validated this, with VM-Series achieving a 99.07% security efficacy score and a perfect 100% Secure by Default rating.
Deep packet inspection, URL filtering, DNS security, malware detection, and zero-day protection all run in the virtual form factor. Micro-segmentation isolates applications within trust zones to prevent lateral movement. The same policies run across AWS, Azure, GCP, VMware, Linux KVM, Nutanix, and Cisco environments. Centralized management through Panorama ties everything together, and Terraform and API support enable infrastructure-as-code automation for deployment and scaling. Automatic policy provisioning during development workflows means security keeps pace with DevOps cycles.
Customers praise the enterprise-grade security parity with physical appliances and the deep application visibility across hybrid environments. The UI and Panorama-based centralized management get consistent positive feedback from security teams of all sizes. Something to be aware of is that performance depends heavily on host instance sizing, which requires careful upfront capacity planning. Initial setup is complex for teams new to the Palo Alto ecosystem.
If your organization runs hybrid or multi-cloud infrastructure and needs consistent NGFW protection across all environments, VM-Series is the market leader in virtual firewalls. Panorama centralization and Terraform support make it a strong fit for teams building cloud-first architectures at scale. The licensing model and resource requirements mean this isn’t a budget option, but for organizations that need this level of coverage, it’s well worth the investment.
Sophos Firewall is a network security platform built on Xstream architecture that consolidates IPS, web filtering, application control, VPN, and sandboxing into a single appliance. We think it’s one of the strongest options for mid-sized organizations and SMBs that need strong protection without requiring a dedicated security engineering team. The Security Heartbeat feature is a standout; it connects the firewall with Sophos-managed endpoints to automatically isolate compromised devices in real time.
Xstream architecture optimizes traffic flow and throughput, while TLS 1.3 inspection runs without downgrading encrypted connections. Machine learning handles threat response against new and emerging attacks, and cloud-based sandboxing contains zero-day threats before they reach the network. Security Heartbeat sends health status updates between endpoints and the firewall every 15 seconds, enabling automated response that closes the gap between detection and containment without manual intervention. Integration with Sophos MDR and XDR extends visibility across the broader security stack.
Customers praise the intuitive interface and the single-dashboard visibility that makes daily administration straightforward. The Security Heartbeat automated isolation feature gets specific praise for stopping real threats. Support responsiveness earns consistent positive marks. Something to be aware of is that reporting lacks customization for building tailored reports with specific fields and export formats. CLI capabilities are limited, which makes bulk configuration tasks harder for experienced administrators.
If your organization needs strong firewall protection with an interface your team can actually use without deep specialization, Sophos Firewall fits that profile well. The cost efficiency stands out; SSL and IPsec VPN connections run on base subscriptions without per-user VPN fees, and MFA uses software authentication at no extra cost. Sophos Central provides centralized cloud management across branch firewalls without additional licensing, which is good to see.
VMware vDefend (now under Broadcom) is a software-defined Layer 2-7 firewall that secures east-west traffic within virtualized environments. Unlike perimeter firewalls, it distributes firewalling to each ESXi host to stop lateral movement between workloads. We think it’s the strongest option available for organizations running VMware infrastructure that need to address east-west traffic security with micro-segmentation.
Lateral traffic inside private clouds runs at roughly four times the volume of perimeter traffic, and that’s exactly where vDefend focuses. The firewall distributes to every host in the environment, enabling micro-segmentation that isolates workloads and prevents attackers from moving laterally after initial compromise. Tag-based rules management handles dynamic environments where IP addresses change constantly. Stateful firewalling, IDS/IPS, sandboxing, and Network Traffic Analysis run at the workload level. Elastic throughput scales automatically with workload demand without manual intervention.
Customers in high-security environments praise the reliability, scalability, and encryption capabilities. The VMware-native integration simplifies deployment for teams already invested in the ecosystem. Tag-based rule management gets positive marks for handling dynamic environments. Something to be aware of is that multi-cloud interoperability is limited for AWS, Google Cloud, and Oracle environments. Incorrect firewall rules can sever all communications with limited rollback safety nets.
If your organization runs VMware infrastructure and needs to address east-west traffic security, vDefend is purpose-built for that problem. The distributed approach fills a gap that perimeter firewalls simply cannot address. Something else to be aware of is that Broadcom’s licensing model has changed; vDefend is only available in the higher licensing tier, which some organizations may find cost prohibitive. Organizations with multi-cloud or multi-vendor architectures should verify interoperability before committing.
WatchGuard Firebox M Series is a unified threat management appliance built for SMBs and MSPs that need enterprise-grade security without enterprise complexity. The refreshed M Series launched in October 2025 delivers up to twice the performance of previous models with multi-gig connectivity up to 10 Gbps per interface. We were impressed by the independent NetSecOPEN testing, which confirms the M Series maintains consistent throughput even with all security services enabled; that’s a distinction many firewalls in this space can’t claim.
The lineup includes five models: M295, M395, M495, M595, and M695, scaling from small enterprises to top-tier deployments with optional redundant power. Integrated AuthPoint MFA runs directly through the Firebox without needing a separate RADIUS server, which simplifies the architecture for smaller teams. URL filtering, intrusion prevention, application control, and ransomware prevention all run from the same appliance. Over 100 dashboards and reports provide detailed network visibility. All models integrate with WatchGuard Cloud for centralized management and XDR-powered detection through ThreatSync.
Experienced firewall professionals praise the security capabilities, intuitive management, and solid documentation. Customers highlight improved network visibility, stable VPN connections, and reduced incident response times. Organizations running WatchGuard long-term report strong stability; one customer described operating across 60 locations via VPN tunnels since 2010 without problems. Something to be aware of is that Policy Manager and Firebox System Manager interfaces feel dated and difficult to navigate.
If your organization needs a firewall that maintains real-world throughput with all security services running and you want MFA built in without extra infrastructure, the Firebox M Series addresses both. Nearly 17,000 MSPs worldwide run the platform, which confirms strong channel ecosystem support. We think it’s well worth considering for SMBs and MSPs that value operational simplicity and modular hardware flexibility. The latest Fireware v2026.2 firmware update confirms active ongoing development.
We researched lots of mobile analytics solutions while we were making this guide. Here are a few other tools worth your consideration:
A cloud-native network firewall solution to protect services running in Azure.
Delivers high security performance, flexible extension, advanced threat detection, and automated policy implementation.
Secures networks against incoming threats and complex DDoS attacks.
A NGFW that integrates AI technology, cloud threat intelligence, and IoT security for comprehensive coverage.
A comprehensive platform focused on maintaining traffic throughput, while ensuring that malicious traffic is stopped.
When evaluating network firewalls, focus on five essential areas. Here’s the checklist of questions you should be asking:
Weight these criteria based on your environment. Enterprises need throughput and policy granularity. SMBs need ease of deployment and intuitive management. MSPs need modular platforms and strong per-customer isolation. Branch offices need deployment simplicity and remote management. Cloud-native teams need API-first architectures and infrastructure-as-code support.
Expert Insights is an independent editorial team that researches, tests, and reviews cybersecurity and IT solutions. No vendor can pay to influence our review of their products. Our recommendations are based solely on product quality and operational value. Before testing, we map the full vendor market for each category, identifying all active vendors from market leaders to emerging challengers.
We evaluated 12 network firewall platforms across performance under security load, policy management depth, cloud integration, and real-world deployment complexity. Each platform was assessed based on published specifications, vendor documentation, and real-world customer feedback, measuring throughput with all security services enabled, evaluating management interface usability, and assessing configuration effort. We focused on operational realities rather than specification sheets.
We also conducted extensive market research and gathered customer feedback across multiple organization sizes to validate vendor claims against operational reality. We spoke with product teams to understand architectural decisions, deployment challenges, and known limitations. Our editorial and commercial teams operate independently. No vendor can pay to influence our review of their products.
This guide is updated quarterly. For full details on our evaluation process, visit our How We Test & Review Products.
No single firewall fits every organization. Your choice depends on your deployment model, team expertise, and whether you prioritize raw performance, policy flexibility, or ecosystem integration.
If you need enterprise-grade firewall performance that scales from branch to data center with hardware acceleration, Fortinet FortiGate is the market benchmark. The universal FortiOS CLI simplifies management, and TAC support handles complex cases well. Evaluate sales practices and renewal terms carefully.
If you’re running hybrid or multi-cloud infrastructure needing consistent NGFW protection, Palo Alto Networks VM-Series is the virtual firewall market leader. Panorama centralization and Terraform support enable infrastructure-as-code workflows.
If you’re an enterprise running workloads across multiple cloud providers needing distributed firewall control, Aviatrix handles east-west and egress security with identity-based policy enforcement.
If you’re an SMB or MSP needing genuine real-world throughput with all security services enabled, WatchGuard Firebox M Series delivers sustained performance verified by independent NetSecOPEN testing. Built-in MFA and modular hardware flexibility simplify operations.
If you’re managing a hybrid environment with multiple offices and cloud providers, Barracuda CloudGen Firewall consolidates firewall and SD-WAN in one platform. Long-term customers report strong stability and support.
If you have Juniper networking expertise and need proven long-term stability, Juniper SRX Series delivers zone-based architecture that has earned its reputation through years of production use.
Read the individual reviews above to dig into deployment specifics, pricing, and the trade-offs that matter for your environment.
Network firewalls are security tools that are designed to prevent malicious actors and dangerous content from accessing your network. They are a means of strengthening your perimeter, allowing you to block, in bulk, any unknown or dangerous elements that try to get into your network.
Historically, firewalls were hardware devices that all network traffic would have had to pass through. While on-premises, hardware firewalls are still available, they can also be deployed as software tools too.
Today’s firewalls are dynamic and proactive pieces of kit. They use features like sandboxing and zero trust access to keep your network safe all of the time, even when encountering new and unknown threats. Malicious actors are constantly looking for new ways to breach your defenses, sandboxing gives you the chance to understand how code will behave before allowing it onto your systems, while zero-trust access embeds a cautious and skeptical approach, decreasing the chances of letting anything slip through the net.
Firewalls act as a secure outer perimeter, monitoring what is able to access your network and what is not, based on pre-set and customizable rules defined by you. Firewalls use a range of in-built technologies to identify threats, however nuanced and well disguised they are. You can adjust security policies to ensure that the firewall is suited to your network specifications.
The four main ways that firewalls assess the content entering your network include:
However, firewalls don’t just filter content – the combination of traffic filtering with other threat protection capabilities is what makes them such a robust line of defense. Some other common firewall capabilities include:
Every organization that uses digital services should be looking to employ some type of firewall because they take a good deal of the work out of addressing network threats. They act as the first line of defense, automatically blocking a high proportion of attacks, which allows you to focus on the more complex or nuanced attacks.
Many of the firewalls on the market today go well beyond offering a secure perimeter. Whilst retaining the ability to filter unwanted and dangerous traffic, they deliver a range of effective security features to make your network as secure as possible. When you are looking to invest in a solution to improve your network security, it is worth considering some of the following features to identify the most appropriate tool for your use-case.
Packet filtering firewalls
As the name would suggest, packet filtering firewalls revolve around the filtering of incoming (and outgoing) packets. It can deny access or exit based on sender and recipient IP addresses, protocols, and ports, referring to predetermined policies set by administrators. Any packets that do not fall in line with these policies are automatically blocked. Access control lists are the protocol within this firewall that dictate what needs to be looked for in packets and what action ought to be taken.
So, what is a packet?
A network packet is, essentially, data sent over a network. Often, large messages struggle to be sent over networks due to their size, so they’re broken down into these smaller packets. Think of breaking a letter down into small notes to be sent. Each of these packets will have a header and a body; the header contains user data and control information, which helps direct the packet to where it needs to go, and the body is the “main message”.
Filtering incoming packets is referred to as Ingress filtering, whereas egress filtering scans outbound information. Ingress filtering is especially useful in determining whether an email is coming from a spoofed IP address. IP spoofing is an attack used by threat actors by changing the source address on an email. Packet filtering can verify whether or not the source address on the email matches the address registered with the packets.
A packet filtering firewall isn’t completely foolproof, however. While it’s a low-cost option that can scan traffic at fast speeds and one device can service the entire network, there are some drawbacks. They’re not often secure, as they will allow any traffic to enter provided it is on an approved port – regardless of whether or not the traffic is malicious. Deploying and managing access control lists can also be time consuming and difficult.
Application-Level Firewalls
Application firewalls (or proxy firewalls) can be seen as a complimentary firewall to packet filtering methods that takes it one step further. With a set of predetermined rules, this firewall will filter and monitor all HTTP traffic that traverse between web applications and the internet. Deployed at the application layer, this firewall essentially serves as the only entrance and exit to each individual application in a network. It does so by in-depth packet filtering, sorting based on characteristics such as destination ports and HTTP request strings. Different policies can be built and customized for each individual application and dictates rules for HTTP connections.
An external user will make a request to access a network which will pass through the application layer firewall, which will then decide whether or not to grant access after verifying the request. In addition to monitoring and granting access, application firewalls can also accept requests to web pages and applications but at the same time mask the identity and IP address of the internal network and devices for added protection. They also offer deep packet inspection.
Application-level firewalls can be deployed as either hardware, software, or a server plug-in. They can cause a slowness of traffic and can be difficult to configure and deploy. It is also one of the more pricier firewall solutions.
Circuit Level Firewalls
Circuit firewalls (or circuit level gateway firewall) assess Transmission Control Protocol (TCP) connections and monitor any active sessions. They work at the session layer in the OSI model. Circuit firewalls, predominantly, assess the security of an established connection after a User Datagram Protocol (UDP) or TCP connection has been completed.
It also works by protecting devices inside the network when they make a connection with a remote host. It does so by creating the connection on behalf of the device, masking the user’s identity and IP address.
While similar to packet filtering firewalls, they take it one step further by verifying established connections. Like packet filtering, it is also a fairly simple and straightforward measure that doesn’t take too much to run in terms of cost and deployment. However, their simplicity is also a drawback in that they cannot monitor data packet contents, meaning that a data packet that contains malware could slip past a circuit firewall if the TCP connection is legitimate. As such, other firewalls are needed in conjunction.
Stateful Firewalls
A stateful firewall monitors active network connection sessions, tracking and sorting traffic based on the destination port. It also scans incoming traffic for any risks or malicious activity. This firewall examines every packet that crosses the network, assessing whether it belongs to an established TCP or another network session. Stateful firewalls can also track and log a packet’s history.
Basic versions of this firewall block any traffic that is coming or going that can be considered harmful. They can detect and flag access attempts by unauthorized individuals and servers. Some more advanced stateful firewalls also have multilayer inspection capabilities, which tracks transactions across multiple protocol layers in the OSI model.
Stateful firewalls are certainly more robust and effective than packet filtering or circuit firewalls but can hinder network performance and can be cumbersome for admins to manage.
Next Generation Firewalls
Next Generation firewalls (NGFW or NextGen firewalls) are a little different to the other firewalls in this list. They’re part of the third generation of firewalls that seek to consolidate traditional firewall methods with additional features in a bid to overcome traditional firewall limitations. At a glance, NextGen firewalls filter traffic as it moves through a network. The filtering capabilities are determined by the ports assigned to applications and traffic.
Capabilities seen in traditional first and second gen firewalls that a next generation firewall also harnesses include: packet filtering, stateful inspection, VPN support, port address translation, and network address translation. Alongside these traditional firewall capabilities, NextGen moves across other layers in the OSI model to deliver a more comprehensive firewall solution. It provides application-level inspection, intel from outside the firewall, intrusion prevention, and offers in depth investigation into packet payloads and signatures to find any harmful activity. It can block DDoS attacks, block breaches from encrypted apps, and provide strong analysis features.
Next generation firewalls aim to consolidate traditional firewall methods with this involved packet inspection without hindering network performance. It’s often regarded as a more advanced stateful firewall. NextGen is a robust firewall solution that offers stronger security than the others on this list. It is a suitable option for companies with remote and hybrid working environments, and for companies that have Bring Your Own Device (BYOD) policies. For all their benefits, NextGen firewalls are often expensive, and configuration and deployment take a skilled team and a lot of time.
Alex is an experienced journalist and content editor. He researches, writes, factchecks and edits articles relating to B2B cyber security and technology solutions, working alongside software experts.
Alex was awarded a First Class MA (Hons) in English and Scottish Literature by the University of Edinburgh.
Laura Iannini is a Cybersecurity Analyst at Expert Insights. With deep cybersecurity knowledge and strong research skills, she leads Expert Insights’ product testing team, conducting thorough tests of product features and in-depth industry analysis to ensure that Expert Insights’ product reviews are definitive and insightful.
Laura also carries out wider analysis of vendor landscapes and industry trends to inform Expert Insights’ enterprise cybersecurity buyers’ guides, covering topics such as security awareness training, cloud backup and recovery, email security, and network monitoring. Prior to working at Expert Insights, Laura worked as a Senior Information Security Engineer at Constant Edge, where she tested cybersecurity solutions, carried out product demos, and provided high-quality ongoing technical support.
Laura holds a Bachelor’s degree in Cybersecurity from the University of West Florida.