Zero Trust Network Access (ZTNA) is a security technology that grants users access to specific applications, not entire networks, based on verified identity, device health, and policy. Every access request is evaluated individually, and nothing is trusted simply because it originates from a particular network or location. ZTNA is the most common way organizations put Zero Trust principles into practice for remote access, and it is increasingly replacing traditional VPN.
Zero Trust vs. ZTNA
The two terms are related but not interchangeable. Zero Trust is a security strategy. As defined in NIST SP 800-207, it assumes no implicit trust is granted to users or devices based solely on their network location or asset ownership, and it focuses on protecting resources rather than network segments. ZTNA is one technology that implements that strategy, specifically for access to private applications and data. A complete Zero Trust program also includes identity, endpoint, data, and workload controls.
The Problem with Perimeter Security
Traditional network security treats users and devices inside the perimeter as trusted and those outside as untrusted. Virtual Private Networks (VPNs) extend that perimeter to remote users, typically granting full network access once a user connects. This model has several weaknesses:
- Broad access. A connected user or device can often reach far more of the network than it needs, across all protocols and ports.
- Lateral movement. If a connected endpoint or credential is compromised, an attacker can use that broad access to move through the network.
- Exposed infrastructure. VPN gateways must be reachable from the public Internet, making them a frequent target for attackers.
How ZTNA Works
Implementations vary by vendor, but most ZTNA solutions share the same basic components.
Policy Engine and Broker
A cloud-based service evaluates each access request against policy. It verifies the user’s identity, typically through an identity provider, checks the device’s security posture, and considers context such as location and risk before allowing a connection to a specific application.
Connectors
Lightweight software connectors installed on the private network, or in the cloud alongside the applications, establish outbound-only connections to the service. Because no inbound connections are required, applications are never directly exposed to the Internet, and there are no public-facing gateways to attack.
Client Agent
A client agent on the endpoint acquires traffic destined for published applications and sends it to the service, which brokers the connection through the connector. Some solutions also offer agentless, browser-based access for web applications.
Core Principles of ZTNA
ZTNA implementations are built on a set of core principles, including the following.
Verify Explicitly
Users and devices must be authenticated and authorized before access is granted, using multifactor authentication (MFA), phishing-resistant credentials, and device health signals such as compliance status.
Least Privilege, Per Application
Access is granted to individual applications, defined by FQDN or IP address along with specific protocols and ports, rather than to the network as a whole. Users receive only the access they need to do their jobs.
Continuous Verification
Trust is not granted once and forgotten. ZTNA solutions re-evaluate access as conditions change, such as when a device falls out of compliance or a user’s risk level increases, and can revoke access in response.
Assume Breach
Because users never receive network-level access, a compromised account or device can reach only the applications it was explicitly granted. This limits the blast radius of an attack. ZTNA complements, but does not replace, network micro-segmentation, which restricts traffic between systems on the internal network.
ZTNA vs. VPN
The table below highlights the key differences between traditional VPN and ZTNA.
| Aspect | Traditional VPN | ZTNA |
| Access Model | Network-level access, often to entire subnets | Per-application access only |
| Trust Model | Trusted once connected | Every request verified against policy |
| Network Exposure | VPN gateways exposed to the Internet | Outbound-only connectors; applications hidden from the Internet |
| Lateral Movement Risk | High | Limited to granted applications |
| Device Posture | Often checked only at connection time, if at all | Evaluated as part of access policy |
| Infrastructure | On-premises gateways, authentication servers, load balancers | Cloud service plus lightweight connectors |
Benefits of ZTNA
There are many benefits associated with ZTNA implementations, including the following.
- Reduced attack surface. Applications and infrastructure are no longer exposed to the public Internet.
- Limited lateral movement. Compromised credentials or devices provide access only to explicitly granted applications.
- Consistent policy everywhere. The same identity-based policy applies whether users are at home, in the office, or traveling.
- Simplified infrastructure. Cloud-delivered ZTNA eliminates most on-premises remote access infrastructure.
- Better user experience. Connections are made through the provider’s nearby edge locations rather than backhauled through a central VPN gateway.
Considerations
ZTNA is not a drop-in replacement for every VPN scenario. Organizations should plan for the following:
- Application discovery. Per-application access requires knowing which applications users need. Many organizations start with broad access rules that mimic VPN, then narrow them over time.
- Domain-joined devices. Traditional Active Directory domain-joined endpoints need broad access to domain controllers and other infrastructure, and some depend on pre-logon connectivity. These requirements are a poor fit for per-application access.
- Licensing. ZTNA services are typically licensed per user, while built-in VPN clients often carry no additional cost.
For a detailed comparison in the Microsoft ecosystem, see Always On VPN vs. Entra Private Access.
ZTNA with Microsoft Entra Private Access
Microsoft Entra Private Access is Microsoft’s ZTNA solution and part of Microsoft Entra Global Secure Access, Microsoft’s Security Service Edge (SSE). It uses the Global Secure Access client on endpoints and the Entra Private Network Connector on the private network, with Microsoft Entra ID and Conditional Access enforcing policy for every published application. It supports Windows, macOS, iOS, and Android.
Summary
Zero Trust Network Access replaces the implicit trust of perimeter-based security and traditional VPN with explicit, per-application access based on identity, device health, and policy. By keeping applications hidden from the Internet and limiting each user to only what they need, ZTNA shrinks the attack surface and contains the impact of compromised credentials or devices. For most organizations, ZTNA is a foundational step in a broader Zero Trust strategy.
Additional Information
Zero Trust Architecture (NIST SP 800-207)
What is Security Service Edge (SSE)?
What is Secure Access Service Edge (SASE)?
What’s the Difference Between SSE and SASE?
Ready to Move Beyond VPN?
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