What is Network Detection and Response (NDR)?

Network Detection and Response (NDR) is a cybersecurity technology that analyzes network traffic to identify suspicious behavior, uncover hidden threats, and accelerate incident response. NDR helps security teams detect attacks that may evade preventive controls by identifying behavioral indicators across managed, unmanaged, and agentless devices throughout the environment.

Why is NDR important in the AI era?

NDR is becoming increasingly important because AI is accelerating both network complexity and the speed of cyberattacks. As users, applications, devices, cloud services, and AI systems generate more encrypted and interconnected traffic, organizations need continuous visibility into network activity to identify risk before it becomes business impact.

What types of threats can NDR detect?

NDR helps identify threats such as command-and-control activity, lateral movement, unauthorized communications, suspicious device behavior, insider threats, and attacks that evade traditional preventive controls. By analyzing network activity and behavioral patterns, NDR can help uncover both known and previously unseen threats.

How does NDR differ from a firewall?

Firewalls and NDR serve complementary roles in network security. Firewalls inspect, control, and block traffic based on security policies, while NDR continuously analyzes network activity to identify suspicious behavior, hidden threats, and attack patterns that may evade preventive controls. Together they provide both prevention and deeper threat detection across the network.

How does NDR complement endpoint security, MDR, and XDR?

No single security control has complete visibility into every user, device, application, and communication across an environment. NDR complements endpoint, firewall, MDR, and XDR by providing network-level visibility into managed, unmanaged, and agentless assets while helping expose attack activity that may otherwise remain hidden.

Sophos NDR is a network detection and response solution that provides deep visibility, behavioral analytics, threat detection, and active response across network traffic. It combines behavioral NDR analytics with IDS/IPS inspection to identify known and unknown threats while sharing network context through Sophos Fusion to support coordinated defense.

What does Sophos NDR see that other security tools may miss?

Sophos NDR provides visibility into unmanaged, unknown, and agentless assets that endpoint-based and other security tools may not fully see. This includes IoT devices, operational technology (OT), printers, cameras, guest devices, legacy systems, and other unmanaged assets that can create security blind spots.

Can Sophos NDR actively respond to threats?

Yes. When deployed in Active Inline mode, Sophos NDR can inspect traffic in real time and automatically drop identified malicious packets before they reach their destination. Passive Inline and SPAN/TAP modes are also available for organizations that prefer monitoring without direct blocking.

Can Sophos NDR detect lateral movement?

Yes. Sophos NDR analyzes network communications and behavioral patterns that may indicate attackers moving between systems after gaining initial access. This visibility helps security teams identify suspicious activity and investigate potential attack paths before threats spread further.

Can Sophos NDR detect threats in encrypted traffic?

Yes. Sophos NDR helps identify threats within increasingly encrypted environments using a combination of behavioral analytics, network inspection, and Encrypted Payload Analytics (EPA). EPA enables Sophos NDR to identify suspicious activity and potential threats without requiring full traffic decryption, helping organizations maintain visibility while supporting privacy, performance, and operational requirements.

How does Sophos NDR work with Sophos Firewall?

Sophos NDR and Sophos Firewall provide complementary visibility and protection across the network. Sophos Firewall delivers high-performance protection, deep inspection, and enforcement, while Sophos NDR expands visibility through network analytics and detection capabilities. Together they contribute shared context through Sophos Fusion to strengthen coordinated defense.

How does Sophos NDR work with Sophos XDR and Sophos MDR?

Sophos NDR provides network telemetry and threat context that can be correlated with signals from endpoints, identities, email, cloud services, and other controls. This helps Sophos XDR and Sophos MDR investigate suspicious activity more efficiently and improve response to multi-stage attacks that span multiple environments.

Can Sophos NDR be purchased as a standalone product?

Yes, Sophos NDR can be purchased as a standalone solution.

How can Sophos NDR be deployed?

Sophos NDR can be deployed as a virtual appliance, on approved third-party hardware, or on dedicated Sophos NDR hardware. Depending on form factor and configuration, organizations can choose Active Inline, Passive Inline, or SPAN/TAP deployment modes to match their security, performance, and operational requirements. This flexibility allows Sophos NDR to support a wide range of network architectures and deployment strategies.

Sophos NDR

Behavioral network detection and inline prevention in one solution

Sophos NDR combines AI- and ML-powered behavioral analytics with proven IDS/IPS inspection to detect known and unknown threats across managed, unmanaged, and agentless assets spanning hybrid environments. Flexible passive and inline deployment options, direct packet blocking in Active Inline mode, and centralized management through Sophos Fusion help you uncover hidden threats, respond faster, and simplify network security operations.

77%

IT teams that lack full visibility across hybrid environments

_{Source: SolarWinds 2026 State of Monitoring & Observability Report}

3.5 hours

Median time for attackers to go after Active Directory after gaining access

_{Source: Sophos Active Adversary Report 2026}

3 days

Median time before an attacker is detected within an environment

_{Source: Sophos Active Adversary Report 2026}

YOUR CHALLENGES

Network blind spots leave threats free to move

Modern networks span users, devices, applications, cloud services, workloads, and unmanaged and agentless assets. Security teams need visibility and context across them to identify threats before they spread.

Distributed networks

Cloud services, remote users, IoT, operational technology, and AI-enabled workloads create visibility gaps that individual controls may not see.

Detection resilience

Preventive controls remain essential, but attackers can evade individual defenses, use valid credentials, and move laterally after initial access.

Operational complexity

Fragmented tools, disconnected workflows, deployment complexity, and alert fatigue make it harder for teams to investigate and respond efficiently.

What customers are saying

"Overall, my experience with Sophos NDR has been quite good. It greatly helps in gaining visibility into abnormal network behavior and detecting patterns that would normally go unnoticed in traditional monitoring. Something I really appreciate is that the alerts are clear and easy to interpret, which speeds up analysis and decision-making.”

IT Security & Risk Management, Banking Industry

Source: Gartner® Peer Insights™

Gartner® and Peer Insights™ are trademarks of Gartner, Inc. and/or its affiliates. All rights reserved.

Gartner Peer Insights content consists of the opinions of individual end users based on their own experiences, and should not be construed as statements of fact, nor do they represent the views of Gartner or its affiliates. Gartner does not endorse any vendor, product or service depicted in this content nor makes any warranties, expressed or implied, with respect to this content, about its accuracy or completeness, including any warranties of merchantability or fitness for a particular purpose.

OVERVIEW

Behavioral detection and active prevention, converged

Sophos NDR extends visibility, detection, and active prevention across the network as part of Sophos Fusion.

See more with network-level visibility into managed, unmanaged, and agentless assets.

Stop threats faster by blocking malicious packets in the network path with Active Inline mode.

Deploy your way on virtual or hardware form factors, with three traffic inspection modes.

Simplify operations with centralized management and shared investigation context in Sophos Fusion.

FEATURES

Sophos NDR: Key components

Sophos NDR brings together behavioral network detection, IDS/IPS inspection, inline response, and flexible deployment, with centralized management through Sophos Fusion, to identify threats, accelerate response, and reduce complexity.

How Sophos NDR delivers

AI- and ML-powered behavioral detection

Behavioral analytics, machine learning, threat intelligence, encrypted traffic analysis, and network analytics help identify suspicious activity and attacker behaviors that signatures alone may miss.

Proven IDS/IPS inspection

Deep packet inspection and signature-based analysis help detect known attacks, indicators of compromise, and malicious traffic patterns across the network.

Active inline response

Active Inline mode inspects traffic in real time and drops identified malicious packets before they reach their intended destination.

Flexible deployment

Deploy as a virtual appliance, on compatible third-party hardware, or on dedicated Sophos NDR hardware using Active Inline, Passive Inline, or SPAN/TAP modes, depending on form factor and configuration.

Shared network context

Sophos NDR contributes network telemetry, detections, and context to Sophos Fusion, enriching investigations with signals from Sophos Firewall, Endpoint, Identity, Email, and Cloud and strengthening Sophos MDR and XDR.

Coordinated defense

Capabilities such as Active Threat Response and Synchronized Security help to automate and coordinate response across the cyber defense system.

Multiple engines to cover known and unknown threats

Sophos NDR combines signature-based and behavioral detection engines to uncover suspicious activity and threats across the network.

Intrusion Prevention System: Actively blocks known-malicious traffic in the network path.
Intrusion Detection System: Flags known threats for investigation.
Encrypted Payload Analytics: Detects zero-day C2 servers and new variants of malware families based on patterns found in the session size, direction, and interarrival times without performing full decryption.
Domain Generation Algorithm: Identifies dynamic domain generation technology used by malware to avoid detection.
Session Risk Analytics: Powerful logic engine utilizes rules that send alerts based on session-based risk factors.
Data Detection Engine: Extensible query engine uses a deep learning prediction model to analyze encrypted traffic for patterns across unrelated network flows and detect port scanning and SSH brute force activity.

Investigate network threats with deeper context

Sophos Fusion and the Sophos NDR Investigation Console give security teams the context and tools to investigate suspicious network activity in greater depth:

Get instant insights into network and application activity, risky flows, and suspicious traffic detections in Sophos Fusion
Drill-down and perform deep forensic investigations with the Investigation Console
Identify all unmanaged, IoT, and potential rogue assets on your network, including their manufacturer and operating system

Flexible deployment for diverse environments

Sophos NDR can be deployed as a virtual appliance, on dedicated Sophos hardware, or on compatible third-party hardware. Active Inline, Passive Inline, and SPAN/TAP deployment modes give you the flexibility to align network security with operational requirements, performance objectives, and risk tolerance. A shared sensor makes it easy to adjust deployment modes as those requirements evolve.

Introducing the Sophos AI-Native Cybersecurity Defense System.

Sophos Fusion

Sophos NDR is part of Sophos Fusion, the industry's most complete cyber defense system, engineered for a world where threats move at AI speed.

Sophos NDR extends the reach of Sophos Fusion across the network, transforming network activity into actionable intelligence that is enriched with endpoint, firewall, email, cloud, identity, and threat intelligence data in the Unified Context Lake. This enables faster detection, investigation, and automated response to active threats.

Learn more about Sophos Fusion

"While NDR delivers value as a standalone detection and response (DR) technology, its strategic importance increases when integrated with endpoint, identity, cloud, application, and security analytics platforms. This convergence improves contextual awareness, reduces alert fatigue, accelerates threat detection and response, and supports the enterprise shift toward unified, AI-driven security operations center (SOC) operati ons and high-fidelity threat detection."

Chris Kissel | Research VP, IDC

Source: 2026 Network Detection and Response Market SWOT Analysis

See why customers choose the Sophos Fusion AI-Native Cybersecurity Defense System

The only vendor to hold Customers’ Choice distinctions across MDR, XDR, Endpoint, Email, and Firewall

Rated the #1 Overall solution in EPP, MDR, XDR, EDR, and Firewall in the G2 Spring 2026 Reports

A Leader in the 2026 IDC MarketScape for Worldwide Managed Detection and Response (MDR) Service for Midmarket

A Leader in the 2026 Gartner Magic Quadrant for Endpoint Protection for the 17th consecutive report

Why Sophos

Sophos Firewall

Strengthen network protection with high-performance inspection, visibility, and automated enforcement.

Protects encrypted, application-rich, and AI-enabled traffic
Reveals users, applications, devices, and activity
Blocks harmful traffic before threats spread

Lean more

Sophos Endpoint

Stop advanced threats with prevention-first endpoint protection and EDR built for AI-era attacks.

Blocks exploits, ransomware, and attacker techniques by default
Raises defenses automatically during active attacks
Accelerates threat hunting, investigation, and response

Learn more

Sophos Managed Detection and Response (MDR)

Extend your team with fully managed, 24/7 detection and response combining AI speed with human judgment.

Investigates and responds to threats in seconds
Integrates with 500+ Sophos and third-party tools
Fully remediates confirmed threats, with no hourly caps

Learn more

Sophos Extended Detection and Response (XDR)

Unify security operations to detect, investigate, and respond to advanced threats across your environment.

Integrates telemetry from Sophos and third-party tools
Uses AI to accelerate investigations and summarize findings
Automates detection, enrichment, and response workflows

Learn more

Sophos Workspace Protection

Protect apps, data, workers, and guests wherever work happens with an integrated, affordable security bundle.

Secures access to private and SaaS applications
Protects sensitive data and controls shadow IT
Applies consistent protection for remote and hybrid workers

Learn more

Sophos Identity Threat Detection and Response (ITDR)

Reduce identity risk across Microsoft Entra ID and Active Directory with continuous assessment, detection, and response.

Identifies misconfigurations, MFA gaps, and risky identities
Detects exposed credentials and abnormal identity activity
Enables rapid containment and remediation actions

Learn more

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Free Trial

If you already have an active Sophos Fusion account, you can access Sophos NDR from Sophos Fusion. Log in to Sophos Fusion, click Free Trials, and select Sophos NDR. Otherwise, fill out this form to begin a free trial.

Once your NDR free trial is activated, deploy an NDR virtual appliance in your network. Follow the Sophos NDR virtual deployment guidance to get started.

Identify known and unknown threats with behavioral detection and IDS capabilities
Gain visibility into suspicious activity and potential threats across your network
Experience Sophos NDR in Sophos Fusion, whether you’re an existing Sophos customer or new to Sophos

Customer Success

Already a customer? Find additional information to inspire, grow your knowledge, troubleshoot, and get help.

Sophos NDR Community

Sophos NDR Support

Sophos NDR Documentation

Sophos NDR Techvids

Frequently asked questions

Network Detection and Response (NDR) is a cybersecurity technology that analyzes network traffic to identify suspicious behavior, uncover hidden threats, and accelerate incident response. NDR helps security teams detect attacks that may evade preventive controls by identifying behavioral indicators across managed, unmanaged, and agentless devices throughout the environment.
NDR is becoming increasingly important because AI is accelerating both network complexity and the speed of cyberattacks. As users, applications, devices, cloud services, and AI systems generate more encrypted and interconnected traffic, organizations need continuous visibility into network activity to identify risk before it becomes business impact.
NDR helps identify threats such as command-and-control activity, lateral movement, unauthorized communications, suspicious device behavior, insider threats, and attacks that evade traditional preventive controls. By analyzing network activity and behavioral patterns, NDR can help uncover both known and previously unseen threats.
Firewalls and NDR serve complementary roles in network security. Firewalls inspect, control, and block traffic based on security policies, while NDR continuously analyzes network activity to identify suspicious behavior, hidden threats, and attack patterns that may evade preventive controls. Together they provide both prevention and deeper threat detection across the network.
No single security control has complete visibility into every user, device, application, and communication across an environment. NDR complements endpoint, firewall, MDR, and XDR by providing network-level visibility into managed, unmanaged, and agentless assets while helping expose attack activity that may otherwise remain hidden.
Sophos NDR is a network detection and response solution that provides deep visibility, behavioral analytics, threat detection, and active response across network traffic. It combines behavioral NDR analytics with IDS/IPS inspection to identify known and unknown threats while sharing network context through Sophos Fusion to support coordinated defense.
Sophos NDR provides visibility into unmanaged, unknown, and agentless assets that endpoint-based and other security tools may not fully see. This includes IoT devices, operational technology (OT), printers, cameras, guest devices, legacy systems, and other unmanaged assets that can create security blind spots.
Yes. When deployed in Active Inline mode, Sophos NDR can inspect traffic in real time and automatically drop identified malicious packets before they reach their destination. Passive Inline and SPAN/TAP modes are also available for organizations that prefer monitoring without direct blocking.
Yes. Sophos NDR analyzes network communications and behavioral patterns that may indicate attackers moving between systems after gaining initial access. This visibility helps security teams identify suspicious activity and investigate potential attack paths before threats spread further.
Yes. Sophos NDR helps identify threats within increasingly encrypted environments using a combination of behavioral analytics, network inspection, and Encrypted Payload Analytics (EPA). EPA enables Sophos NDR to identify suspicious activity and potential threats without requiring full traffic decryption, helping organizations maintain visibility while supporting privacy, performance, and operational requirements.
Sophos NDR and Sophos Firewall provide complementary visibility and protection across the network. Sophos Firewall delivers high-performance protection, deep inspection, and enforcement, while Sophos NDR expands visibility through network analytics and detection capabilities. Together they contribute shared context through Sophos Fusion to strengthen coordinated defense.
Sophos NDR provides network telemetry and threat context that can be correlated with signals from endpoints, identities, email, cloud services, and other controls. This helps Sophos XDR and Sophos MDR investigate suspicious activity more efficiently and improve response to multi-stage attacks that span multiple environments.
Yes, Sophos NDR can be purchased as a standalone solution.
Sophos NDR can be deployed as a virtual appliance, on approved third-party hardware, or on dedicated Sophos NDR hardware. Depending on form factor and configuration, organizations can choose Active Inline, Passive Inline, or SPAN/TAP deployment modes to match their security, performance, and operational requirements. This flexibility allows Sophos NDR to support a wide range of network architectures and deployment strategies.

Sophos NDR

Behavioral network detection and inline prevention in one solution

Network blind spots leave threats free to move

Distributed networks

Detection resilience

Operational complexity

What customers are saying

Behavioral detection and active prevention, converged