Microsegmentation with NSX-T: Enforcing Tenant-Specific Policies in VMware Cloud Director

A Practical Guide to Multi-Tenant Security Through VCD

As security threats become more sophisticated and workloads grow more distributed, microsegmentation has become a foundational security strategy. With VMware NSX-T deeply integrated into VMware Cloud Director (VCD), cloud providers now have the tools to deliver fine-grained, tenant-specific firewall policies—without complex manual configurations.

This article walks through how microsegmentation can be applied per tenant through VCD, offering stronger isolation, better visibility, and policy automation in a multi-tenant cloud environment.

What is Microsegmentation?

Microsegmentation is a security technique that:

• Breaks down the network into smaller segments
• Applies granular firewall policies between workloads
• Controls east-west traffic inside a tenant or application

With NSX-T and VCD, this functionality is fully integrated into the cloud platform, allowing each tenant to manage their own security policies independently.

NSX-T + VCD Architecture Overview

In a typical setup:

• Tenants have their own OrgVDCs
• Each OrgVDC is mapped to an NSX-T Tier-1 Gateway
• Distributed Firewall (DFW) policies are enforced at the hypervisor level
• Security Groups and Tags are used to dynamically assign workloads to policies

Hands-On: Applying Per-Tenant Security Policies

Step-by-Step: Enforcing Web-to-App Tier Isolation

Scenario: A tenant wants to allow only HTTP/HTTPS traffic from the Web tier to the App tier.

1. Define Security Tags in NSX:
   • tag:web and tag:app
2. Assign Tags in VCD:
   • Use VM metadata or Extensibility actions to tag VMs on deployment
3. Create Dynamic Groups:
   • Web-Tier-Group: VMs with tag:web
   • App-Tier-Group: VMs with tag:app
4. Create a DFW Rule in Tenant Portal:
   • Source: Web-Tier-Group
   • Destination: App-Tier-Group
   • Service: HTTP, HTTPS
   • Action: Allow
5. Apply a Deny-All Rule below it to block everything else

✅ Result: Only permitted traffic flows between the tiers, ensuring least privilege access.

Benefits for Multi-Tenant Clouds

• Self-Service Security: Tenants can manage their own firewall rules without provider intervention
• Dynamic & Scalable: Policies automatically apply based on tags and groups
• East-West Visibility: Logs and flows can be monitored per tenant
• Compliance-Ready: Ideal for regulated industries requiring segmentation (e.g., PCI-DSS, HIPAA)