ZTNA and VPN can both provide secure remote access, but they solve different problems. This guide gives IT managers and small businesses a repeatable way to compare them across security controls, identity, deployment effort, user experience and cost—then decide whether to retain a VPN, adopt zero trust network access, or use both during a phased transition.
Overview
A traditional business VPN creates an encrypted connection between an approved device and a private network. After authentication, the user may be placed on the network or a defined segment, depending on the VPN design and access rules. This model is familiar, widely supported and often practical when employees need access to several internal systems.
Zero trust network access (ZTNA) takes a different approach. Rather than extending the network to the user, it brokers access to specific applications or services. Decisions can consider identity, device posture, location, authentication strength and policy. The principle is not that every user or device is automatically unsafe, but that access should be continuously evaluated and limited to what is required.
The choice is therefore not simply “VPN versus ZTNA.” It is a comparison between network-level access and application-level access. A VPN may remain suitable for legacy systems, private infrastructure and teams with straightforward requirements. ZTNA may be a better fit where users need selective access to cloud and internal applications, where contractors require limited permissions, or where reducing network exposure is a priority.
Neither technology replaces basic security controls. Strong identity management, phishing-resistant authentication where practical, patching, endpoint protection, logging, backup and incident response remain necessary. For a wider checklist, see our guide to remote access security for small businesses.
How to estimate the better fit
Start with a simple weighted score rather than relying on a product label. List the requirements that matter to your organisation, assign each a weight from 1 to 5, and score each approach from 1 to 5. Multiply the weight by the score, then add the results.
Weighted score = requirement weight × solution score
Useful requirements include:
- Application scope: Do users need an entire private network, or only a small number of applications?
- Identity control: Can access be linked to central identity, role, group and authentication policies?
- Device assurance: Must access depend on encryption, patch status, endpoint protection or managed-device checks?
- Segmentation: How important is it to prevent a user who reaches one application from discovering others?
- Legacy compatibility: Do systems depend on private IP addresses, network discovery, unusual ports or older protocols?
- Administration: How much time can the team spend designing policies, integrating identity and supporting users?
- User experience: Will users understand the connection method, and can access be made reliable across home and mobile networks?
- Commercial cost: What are the licence, infrastructure, support, migration and training costs?
Use the score as a discussion tool, not as a supposed security measurement. A high total does not compensate for a critical weakness. For example, if a proposed design cannot support a business-critical application, it should not proceed merely because its overall score is attractive.
It is also useful to estimate the full cost of ownership:
Total cost of ownership = licences and infrastructure + implementation + administration + support + migration
Keep one-off and recurring costs separate. A solution with a lower purchase price may require more manual administration, while a platform with broader identity and device integrations may reduce operational work. Use your own staffing rates and supplier quotes rather than relying on generic pricing claims.
Inputs and assumptions
Good comparisons depend on accurate inputs. Record the following before selecting a model:
- User groups: employees, administrators, contractors, suppliers and temporary workers often need different access policies.
- Application inventory: classify each application as cloud-hosted, private, browser-based, client-server, remote desktop or infrastructure service.
- Access frequency: identify occasional access, daily access, always-on workflows and machine-to-machine connections.
- Device types: include managed laptops, personal devices, mobile devices, servers and specialist equipment.
- Identity maturity: note whether a central identity provider, single sign-on, multi-factor authentication and joiner-mover-leaver process already exist.
- Network constraints: document sites, firewalls, private addressing, DNS dependencies, bandwidth and systems that cannot be modified quickly.
- Operational capacity: estimate who will create policies, investigate alerts, handle access requests and troubleshoot connections.
Assume that VPN and ZTNA configurations can both be implemented securely if they are correctly designed and maintained. In practice, outcomes depend on policy quality, authentication, endpoint condition, logging and response. A VPN with tightly scoped routes and strong identity controls may be safer for a particular workload than a poorly governed ZTNA deployment. Conversely, a broad VPN that grants unnecessary network visibility may create avoidable risk.
Do not treat encryption alone as proof of secure remote access. A secure tunnel protects traffic in transit, but it does not decide whether the user should reach a particular application or whether the device is trustworthy. Review authentication, authorisation, segmentation, session controls, audit logs and emergency revocation together.
Worked examples
Example 1: Small office with legacy systems
Suppose a small business has a single office, a modest number of managed laptops and several internal systems that rely on private network access. The team has limited security administration time, and most remote users need the same group of services.
In this situation, a business VPN may score well for compatibility, simplicity and predictable user support. The design should still use individual accounts, multi-factor authentication, least-privilege routes, current protocols, logging and a tested process for removing access. Avoid giving every remote user unrestricted access to the entire internal network. If remote desktop is involved, follow a design that avoids exposing RDP directly to the internet; our secure remote desktop guide covers the relevant considerations.
Example 2: Cloud-first business with contractors
Now consider a business where most applications are cloud-hosted, employees use managed devices, and contractors need access to one or two internal web applications for limited periods. Here, ZTNA may score higher because access can be organised around applications, identities and specific policies rather than broad network membership.
The organisation should still test application compatibility, define contractor expiry dates, connect access to the joiner-mover-leaver process and verify that logs are available to the people responsible for investigations. Temporary access should not remain active simply because a project has ended informally. See our guide to secure access for contractors for a more focused review.
Example 3: Mixed environment during migration
Many organisations will land on a hybrid model. A VPN can support legacy infrastructure while ZTNA protects selected web applications and reduces access for third parties. To estimate the transition cost, list applications by migration difficulty, then calculate implementation effort for each group. Begin with a low-dependency application, measure help-desk contacts and review access logs before expanding.
During a pilot, compare failed logins, access-request volume, connection reliability, policy exceptions and time spent troubleshooting. These operational measures are more useful than a launch date alone. For VPN-specific connection issues, the VPN troubleshooting guide may help identify recurring DNS, login or kill-switch problems.
When to recalculate
Revisit the comparison whenever the inputs change. At minimum, recalculate after a major cloud migration, office closure, acquisition, identity-platform change, device-management rollout or change in contractor use. Also review the model when a critical application is replaced, a supplier changes its access requirements, or the organisation experiences a remote-access incident.
Commercial assumptions should be refreshed when licences, infrastructure requirements, support arrangements or staffing responsibilities change. Security assumptions should be refreshed when authentication policy, endpoint standards, segmentation or monitoring capability changes. Keep the date, assumptions and owner beside the calculation so the result can be understood later.
Use this action plan:
- Inventory users, devices, applications and current access paths.
- Separate legacy, cloud, contractor and privileged-access requirements.
- Score VPN and ZTNA against weighted business and security requirements.
- Calculate one-off and recurring costs using organisation-specific inputs.
- Pilot the preferred model with a representative, low-risk application.
- Test authentication, authorisation, logging, revocation, failure recovery and user support.
- Document exceptions, owners and a date for the next review.
The practical conclusion is usually workload-specific: choose a VPN where network-level access and legacy compatibility are central, choose ZTNA where granular application access and identity-aware policy are more important, and use a controlled hybrid approach when the environment cannot change at once. The best secure remote access model is the one your team can enforce, monitor and update as the business changes.
