Network Isolation of Microsoft Foundry Resources

Introduction

AI Agents can be compared to a human having extended access to the vault of cash. Agents have the capability to act, not just respond. The strategy of network security shifts from just protecting data at rest to protecting the entire ecosystem itself, preventing this fleet of agents from being turned into the weapons against the system they were built to serve. Hence, network security of Agentic AI workloads has gained immense importance. AI Agents are like giving an employee unrestricted access to the company vault — they have the capability to act, not just respond. The network security strategy must therefore shift: from merely protecting data at rest to safeguarding the entire ecosystem, preventing this fleet of agents from being weaponized against the very systems they were built to serve. Network security for Agentic AI workloads has never been more critical.

Microsoft provides two primary options for network isolation:

1.     Azure Private Network (Build Your Own BYO)

2.     Managed Virtual Network (Managed VNet)

This article explains how network isolation can be achieved by both the options and provides recommendations for Enterprise Implementation.

Option 1: Network Isolation using Azure Private Network (BYO)

When an enterprise brings its own virtual network (BYO), a standard private networking setup can be seamlessly implemented for the Foundry Agent Service. The private network provides the following benefits:

1.     Inbound and outbound traffic controls are fully customizable

2.     Local resources within the network are accessible without additional configuration

3.     The platform network can seamlessly access private resources

See the architecture diagram below:

Option 2: Managed Virtual Network (Managed VNet)

Traditionally, network engineers build a protective perimeter around Azure resources such as Virtual Machines and SQL Managed Instances. With Managed Virtual Networks, Azure takes this responsibility off your hands by providing a fully managed, protected network for Foundry resources. It is a Microsoft-managed virtual network that secures the Agent service’s underlying compute within Foundry projects, restricts what agents can access, and helps prevent data exfiltration — all while enabling connectivity to approved Azure resources.

See the architecture diagram below:

Side-by-Side Comparison: Managed VNet vs. BYO Private Network

Decision Tree

Decision Tree

Recommendation

Given the current limitations of Managed VNet, a cautious approach is strongly recommended when considering it for network isolation of Microsoft Foundry Resources. The feature needs to mature further before it is truly ready for Enterprise-grade use, particularly given its Preview status and support for internal MCP tools. For now, Azure Private Network (Build Your Own) remains the preferred and more reliable choice for Enterprise Agentic AI implementations.

References

1. Microsoft Learn: Use virtual networks with Azure AI Foundry Agent Service

2. Microsoft Learn: Configure managed virtual network isolation for Azure AI Foundry

About the author

G,Prabhudesai (08/09/2026) (6) Network Isolation of Microsoft Foundry Resources | LinkedIn