Entra On-Prem Apps: How to Secure On-Prem Applications with Entra ID

Many organizations standardize on Microsoft Entra ID for identity, single sign-on (SSO), multi-factor authentication (MFA) and access control, but still rely on on-prem apps that were never designed for modern authentication. These applications often include legacy web apps, intranet portals, ERP systems, finance tools, supplier portals, and custom internal applications that do not natively support modern identity protocols.

This creates a common challenge. Security teams want to protect on-prem apps with Entra ID, enforce MFA, and centralize access policies. Application teams, meanwhile, want to avoid risky code changes to brittle or business-critical systems.

Datawiza Access Proxy helps solve this problem by placing a modern authentication layer in front of existing applications. That makes it possible to secure on-prem apps with Entra ID without rewriting the applications themselves.

What are on-prem apps in an Entra ID environment?

In this context, on-prem apps are web applications hosted in private data centers, internal networks, or private cloud environments that organizations want to protect with Microsoft Entra ID.

These often include:

• internal business applications
• legacy line-of-business web apps
• ERP and finance portals
• supplier and partner portals
• self-hosted custom applications
• applications that span on-prem, private cloud, and hybrid environments

For many organizations, these apps are still essential to daily operations, even though they were not built with modern authentication and centralized identity in mind.

Why on-prem apps are hard to secure with Entra ID

Securing on-prem apps with Entra ID sounds simple in theory, but in practice, it often becomes one of the hardest parts of an identity modernization project.

Common reasons include:

• the application does not support SAML or OIDC natively
• the existing login flow is fragile or vendor-controlled
• code changes are expensive, slow, or risky
• each application has its own authentication model
• security teams want consistent MFA and access policies across all apps, not just SaaS apps

As a result, many organizations modernize identity for cloud apps first, then get stuck when they reach older internal or self-hosted applications.

How to secure on-prem apps with Entra ID without rewriting the application

A practical way to protect on-prem apps with Entra ID is to place a proxy in front of the application.

With Datawiza Access Proxy, the flow is straightforward:

1. A user accesses the application URL.
2. Datawiza Access Proxy intercepts the request.
3. The user is redirected to Microsoft Entra ID for authentication.
4. After successful authentication, access is granted to the application.
5. The application continues running as it always has, without requiring a rewrite.

This approach lets organizations extend modern identity to older applications while minimizing disruption to the app itself.

Why not Microsoft Entra App Proxy for some on-prem apps?

Microsoft Entra App Proxy can be a good fit in many environments, but its architecture often means user traffic traverses Azure on the way to your on-premises application.

With Datawiza Access Proxy, you can deploy the proxy inside your network, so application traffic stays internal—while Microsoft Entra ID still provides cloud-based authentication and policy enforcement (MFA / Conditional Access).

Want a deeper comparison? See our detailed breakdown of Datawiza as an alternative to Microsoft Entra App Proxy.

Why organizations use Datawiza for on-prem apps

Add Entra ID SSO to existing applications

Many on-prem apps were never built to integrate directly with modern identity platforms. Datawiza makes it possible to place Entra ID in front of those applications so users can sign in through a more consistent enterprise identity flow.

Extend MFA to legacy and self-hosted apps

Older applications often become the weakest point in an access strategy because they cannot easily support stronger authentication on their own. By placing Entra ID in front of the app, organizations can extend MFA protection to systems that would otherwise remain outside modern identity controls.

Avoid risky application changes

Rewriting authentication inside legacy or vendor-managed applications can introduce cost, delay, and operational risk. A proxy-based approach reduces the need for application changes and helps teams modernize access faster.

Centralize access control across more of the application estate

Without a consistent approach, every internal application becomes its own identity project. Datawiza helps organizations bring more on-prem apps under a centralized access model using Entra ID as the identity layer.

Where Datawiza fits for on-prem app modernization

Organizations often have a mix of SaaS apps, cloud-native apps, custom internal apps, and older on-prem systems. The challenge is not whether Entra ID should be part of the identity strategy. It usually already is. The real challenge is how to extend that strategy to applications that were never designed for it.

That is where Datawiza fits. It acts as a modern access layer in front of the application, allowing organizations to adopt Entra ID for authentication without waiting for each app team to redesign login flows or rebuild the application.

This is especially useful when:

• the app is legacy or vendor-managed
• the application cannot safely be modified
• rollout speed matters
• the organization wants a practical path to modernize many apps, not just one
• teams need a simpler way to apply stronger access controls to older systems

Common types of on-prem apps to secure with Entra ID

Organizations commonly use this approach for:

• intranet applications
• ERP and finance systems
• HR and operations portals
• supplier and partner applications
• custom line-of-business web apps
• internal administrative portals
• hybrid environments where some apps remain private while identity is centralized

These systems are often among the most important applications in the environment, yet they are also the most difficult to modernize through direct code changes alone.

Benefits of securing on-prem apps with Entra ID through a proxy-based approach

A proxy-based approach can help organizations modernize access for existing applications more efficiently.

Key benefits include:

• a more consistent sign-in experience across applications
• stronger authentication in front of older systems
• less dependence on outdated login methods
• faster rollout compared with full application rewrites
• better alignment between security goals and application realities

For organizations that want to modernize access without disrupting business-critical apps, this can be a much more practical path.

Secure on-prem apps with Entra ID without rewriting them

If your organization uses Microsoft Entra ID but still depends on legacy or self-hosted web applications, you do not have to leave those systems behind.

Datawiza Access Proxy helps you secure on-prem apps with Entra ID by adding a modern authentication layer in front of existing applications. That means you can extend SSO, MFA, and centralized access control to important business applications without rewriting them.

If you are looking for a practical way to modernize access for on-prem applications, Datawiza can help you move faster with less risk.

👉 Book a demo to see how Datawiza helps secure on premises apps with Entra ID.