Microsoft Foundry Portal: Private Networking Comparison¶

New Foundry Portal vs. Classic Foundry Portal¶

This document provides a comprehensive comparison of private networking capabilities between the new Microsoft Foundry portal experience and the classic Foundry portal experience.

Last Updated: January 2026
Important: This document is based on official Microsoft documentation. Private networking support in the new Foundry portal may change as Microsoft continues to develop the platform.

Executive Summary¶

Capability	New Foundry Portal	Classic Foundry Portal
End-to-end network isolation	❌ Not Supported	✅ Supported
Projects with disabled public network access	❌ Not Supported	✅ Supported
Private endpoint access to Foundry	❌ Portal UI doesn't work	✅ Supported
Managed virtual network for Agents	⚠️ Preview (Classic experience only)	✅ Supported
Custom VNet for Agents	❌ Not Supported	✅ Supported (GA)
Private MCP servers in VNet	❌ Not Supported	❌ Not Supported
Hosted Agents with network isolation	❌ Not Supported	❌ Not Supported

Key Limitation: New Foundry Portal Does Not Support Network Isolation¶

When attempting to switch a network-isolated project to the new Foundry portal experience, users receive the following error:

"Your current setup uses a project, resource, region, custom domain, or disabled public network access that isn't supported in the new Foundry experience yet. To continue, select a different project with a supported configuration."

Official Documentation Statement¶

From How to configure a private link for Microsoft Foundry (Foundry projects):

"End-to-end network isolation in Foundry is not support in the new Foundry portal experience. End-to-end network isolation in Foundry is not supported for the new version of the Agent service. Use the classic Foundry portal experience with the current version of Agent service to securely access your Foundry projects when network isolation is enabled."

And:

"End-to-end network isolation isn't supported in the new Foundry portal experience. Use the classic Foundry portal experience or the SDK or CLI to securely access your Foundry projects when network isolation is enabled."

Detailed Feature Comparison¶

1. Private Link / Private Endpoint Support¶

New Foundry Portal¶

Status: Not Supported for portal access
Private endpoints can be created for the Foundry resource
However, the new portal UI cannot be used to access projects with private endpoints when public network access is disabled

Classic Foundry Portal¶

Status: Fully Supported
Private endpoints work for secure access to Foundry projects
Users can access network-isolated projects through the portal

Reference: How to configure a private link for Microsoft Foundry (Foundry projects)

2. Managed Virtual Network for Foundry Projects¶

New Foundry Portal¶

Status: ⚠️ Preview Feature - BUT requires Classic experience
Managed virtual network is a preview feature for securing Agents service compute
Critical Limitation: "Supports only Standard BYO resources Agents v1 and the Foundry classic experience"

Classic Foundry Portal¶

Status: Supported (Preview)
Full support for managed virtual network isolation
Can be deployed via Bicep template

Supported Regions for Managed VNet: - East US, East US2, Japan East, France Central, UAE North - Brazil South, Spain Central, Germany West Central, Italy North - South Central US, West Central US, Australia East, Sweden Central - Canada East, South Africa North, West Europe, West US, West US 3 - South India, UK South

Reference: Configure managed virtual network for Microsoft Foundry projects

3. Custom Virtual Network (BYO VNet) for Agents¶

New Foundry Portal¶

Status: Not Supported

Classic Foundry Portal¶

Status: GA (Generally Available)
Full network isolation through virtual network injection
Supports Standard Agent deployment and evaluations

Reference: How to use a virtual network with the Azure AI Agent Service

4. Agent Service Network Isolation¶

New Foundry Portal¶

Status: Not Supported
The new version of the Agent service does not support end-to-end network isolation

Classic Foundry Portal¶

Status: Supported
Network injection for Standard Agents and evaluations
Protects against data exfiltration

Important Limitations (Both Portals): - Hosted Agents are not supported with end-to-end network isolation - Private MCP servers deployed in the same virtual network are not supported - only publicly accessible MCP servers can be used - Basic Agents don't require network isolation

Reference: How to configure a private link for Microsoft Foundry (Foundry projects) - Limitations

5. Disabled Public Network Access¶

New Foundry Portal¶

Status: Not Supported
Projects with publicNetworkAccess: Disabled cannot be accessed through the new portal

Classic Foundry Portal¶

Status: Supported
Full support for projects with disabled public network access
Access via private endpoints, VPN Gateway, ExpressRoute, or Azure Bastion

Reference: How to configure a private link for Microsoft Foundry (Foundry projects)

Workarounds for Network-Isolated Projects¶

If you have a network-isolated Foundry project, you have the following options:

Option 1: Use the Classic Foundry Portal¶

Continue using the classic experience at https://ai.azure.com with your private network configuration.

Option 2: Use SDK or CLI¶

Access your Foundry projects programmatically when network isolation is enabled: - Azure CLI - Azure SDKs (Python, .NET, etc.) - REST APIs

Option 3: Enable Public Network Access (Not Recommended for Production)¶

If you temporarily need new portal access for non-sensitive work: 1. Go to Azure Portal → Your Foundry Project 2. Navigate to Networking → Firewalls and virtual networks 3. Select All networks 4. Save changes

⚠️ Warning: This exposes your project to the public internet and is not recommended for production environments with sensitive data.

Managed Virtual Network Limitations (Preview)¶

When using managed virtual network isolation (preview feature), note these limitations:

Deployment Method: Can only be deployed via the Bicep template in foundry-samples repository
Portal Experience: Supports only Foundry classic experience, not the new portal
Firewall Costs: FQDN outbound rules in "Allow Only Approved Outbound" mode create a managed Azure Firewall with associated costs
No Rollback: Cannot disable managed virtual network isolation after enabling it
Outbound Rules: Must be created through Azure CLI
MCP Tools: End-to-end network isolation for Agent MCP tools with managed virtual network is not supported
Preview Registration: Requires preview feature registration for AI.ManagedVnetPreview flag

Reference: Configure managed virtual network for Microsoft Foundry projects - Limitations

Network Architecture Comparison¶

Classic Portal with Custom VNet (GA)¶

┌─────────────────────────────────────────────────────────────────┐
│                     Customer Virtual Network                     │
│  ┌─────────────┐    ┌─────────────┐    ┌─────────────┐         │
│  │   Client    │    │  Private    │    │   Foundry   │         │
│  │   (VM/VPN)  │───▶│  Endpoint   │───▶│   Project   │         │
│  └─────────────┘    └─────────────┘    └─────────────┘         │
│         │                                      │                 │
│         │           Private Endpoints          │                 │
│         │    ┌──────────────────────────┐     │                 │
│         │    │  ┌────────┐ ┌────────┐  │     │                 │
│         └───▶│  │Storage │ │AI Search│  │◀────┘                 │
│              │  └────────┘ └────────┘  │                        │
│              │  ┌────────┐ ┌────────┐  │                        │
│              │  │Cosmos  │ │Key Vault│  │                        │
│              │  └────────┘ └────────┘  │                        │
│              └──────────────────────────┘                        │
└─────────────────────────────────────────────────────────────────┘

New Portal (Public Access Only)¶

┌─────────────────────────────────────────────────────────────────┐
│                        Public Internet                           │
│                              │                                   │
│                              ▼                                   │
│                    ┌─────────────────┐                          │
│                    │   New Foundry   │                          │
│                    │     Portal      │                          │
│                    │  (ai.azure.com) │                          │
│                    └─────────────────┘                          │
│                              │                                   │
│                              ▼                                   │
│                    ┌─────────────────┐                          │
│                    │    Foundry      │                          │
│                    │    Project      │                          │
│                    │ (Public Access) │                          │
│                    └─────────────────┘                          │
│                                                                  │
│  ❌ Projects with private networking cannot be accessed          │
└─────────────────────────────────────────────────────────────────┘

Recommendations¶

For Production Environments Requiring Network Isolation¶

Use the Classic Foundry Portal until the new portal supports private networking
Deploy using the custom virtual network (BYO VNet) approach which is GA
Use SDK/CLI for programmatic access to network-isolated resources

For Development/Testing Without Sensitive Data¶

Consider using the new portal with public network access
Use Azure RBAC and identity-based security as alternative protection layers

For Future Planning¶

Monitor Microsoft documentation for updates on new portal network isolation support
Plan migration path when new portal gains network isolation capabilities
Consider the managed virtual network preview for new deployments if preview features are acceptable

Official References¶

Topic	URL
Configure private link for Foundry projects	https://learn.microsoft.com/en-us/azure/ai-foundry/how-to/configure-private-link?view=foundry
Configure managed virtual network for Foundry projects	https://learn.microsoft.com/en-us/azure/ai-foundry/how-to/managed-virtual-network?view=foundry
Configure private link for Foundry hubs (hub-based projects)	https://learn.microsoft.com/en-us/azure/ai-foundry/how-to/hub-configure-private-link?view=foundry-classic
Configure managed network for Foundry hubs	https://learn.microsoft.com/en-us/azure/ai-foundry/how-to/configure-managed-network?view=foundry-classic
Virtual networks with Azure AI Agent Service	https://learn.microsoft.com/en-us/azure/ai-foundry/agents/how-to/virtual-networks?view=foundry-classic
Azure AI Foundry security baseline	https://learn.microsoft.com/en-us/security/benchmark/azure/baselines/azure-ai-foundry-security-baseline
Foundry samples - Managed VNet Bicep template	https://github.com/azure-ai-foundry/foundry-samples/tree/main/infrastructure/infrastructure-setup-bicep/18-managed-virtual-network-preview
Upgrade from Azure OpenAI to Microsoft Foundry	https://learn.microsoft.com/en-us/azure/ai-foundry/how-to/upgrade-azure-openai?view=foundry-classic

Changelog¶

Date	Change
January 2026	Initial documentation based on Microsoft Learn documentation

This document is maintained as part of the Azure Architecture Guidance repository. For corrections or updates, please submit a pull request.