ZTNA gives a verified user access to one specific application, rather than dropping them onto the network the way a VPN does.
The short answer
Zero trust network access checks identity, device and context on every request, then grants access to a single resource for that session. Internal systems are never published to the internet, so an attacker cannot reach what they cannot see. It replaces the VPN model of authenticate once, then roam.
The problem it solves is lateral movement. With a VPN, one stolen credential puts an attacker inside the network, able to scan for whatever else is reachable. ZTNA removes that, because being on the network is no longer what grants access.
On this page
ZTNA compared with a VPN
What gets checked
Every request is evaluated, not just the first one. A session that was valid an hour ago is re-evaluated when the device state changes.
| Signal | Example condition |
|---|---|
| Identity | Authenticated user, MFA satisfied, in the right group |
| Device | Managed device with the agent installed and healthy |
| Resource | Access granted to one application, not to a network range |
| Context | Location, time and session risk considered on each request |
When a startup needs it
Usually at one of three moments: an internal tool needs to be reachable by a distributed team, a contractor needs access to one system and nothing else, or an auditor asks how administrative access to production is restricted. A VPN answers all three badly, because it grants more than any of them require.
How Osto runs ZTNA
Osto provisions a private domain for your cloud servers and internal resources. Those resources stay unreachable unless the Osto endpoint agent is installed and MFA is satisfied, so the systems that were never wired into single sign-on are still gated. Because ZTNA sits in the same platform as endpoint control, IAM and the SIEM, an access attempt is recorded alongside what happened on the device before and after it.
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Frequently asked questions
What does ZTNA stand for?
Zero trust network access. It grants access to individual applications after verifying identity, device and context on each request, instead of placing the user on the internal network.
Is ZTNA the same as a VPN?
No. A VPN authenticates once and then connects the user to a network, where anything reachable can be probed. ZTNA authorises access to one resource at a time and keeps everything else invisible, which removes the lateral movement a stolen VPN credential would allow.
Does ZTNA replace MFA?
No, it depends on it. MFA proves who the user is; ZTNA decides what that verified user may reach, and re-checks on every request. In practice ZTNA is where MFA gets enforced for systems that sit outside single sign-on.
Do auditors ask about ZTNA specifically?
They ask about the outcome rather than the technology: how remote and administrative access is restricted, how it is authenticated, and how it is logged. ISO 27001 covers this under A.5.15 access control and A.8.5 secure authentication.