What is Application Proxy in Azure AD?

Application Proxy in Azure AD (Microsoft Entra ID) is a secure remote access solution that allows users to access on-premises applications from anywhere without using a VPN. It provides single sign-on (SSO) and conditional access while keeping internal resources protected.

Key Features of Azure AD Application Proxy

1. Secure Remote Access
   • Users can access on-premises apps via Microsoft Entra ID authentication.
   • No need to expose internal apps directly to the internet.
2. Single Sign-On (SSO) Support
   • Integrates with Azure AD SSO, reducing password prompts.
3. Conditional Access Policies
   • Enforce MFA, IP restrictions, and compliance rules before granting access.
4. No VPN Required
   • Works over HTTPS, eliminating the need for a traditional VPN or DMZ exposure.

How Azure AD Application Proxy Works

1. Application Proxy Connector
• A lightweight agent installed on an on-premises server acts as a bridge between internal applications and Azure AD.
2. User Authentication via Azure AD
• When a user tries to access an internal web app, they are authenticated through Azure AD before the request is sent to the on-prem server.
3. Reverse Proxy Redirection
• The request is securely routed via the Azure cloud, without exposing internal IP addresses.

Example Proxy URL:

https://appname-yourtenant.msappproxy.net

Common Use Cases for Azure AD Application Proxy

1. Secure Access to Legacy Apps: Enable remote access to On-premises apps that don’t support modern authentication
2. Remote Work Enablement: Allow employees to securely access intranet sites, HR portals, or other internal web apps.
3. Partner & Vendor Access: Provide controlled access to specific internal applications without exposing your entire network.

How to Configure Azure AD Application Proxy

Admins can set up Application Proxy in the Microsoft Entra Admin Center:

1. Install the Connector on an on-premises server.
2. Register the Application in Azure AD.
3. Publish the Application with external and internal URLs.

PowerShell Cmdlet to List Proxied Apps:

Get-AzureADApplicationProxyApplication

Best Practices

1. Use Conditional Access: Require MFA and restrict access based on user identity and device compliance.
2. Monitor Access Logs: Regularly check audit logs in Microsoft Entra ID for unusual activity.
3. Limit Permissions: Assign access to only specific user groups instead of making apps public.

Azure AD Application Proxy ensures secure, seamless access to on-prem applications while protecting your internal environment from external threats.

Explore More

• Get-AzureADApplicationProxyApplication