Getting Started – Microsegmentation using NSX Distributed Firewall

Created by nikhilvmw on Sep 4, 2014 9:33 AM. Last modified by nikhilvmw on Sep 4, 2014 9:35 AM.
VMware NSX for vSphere, release 6.0.x.


This document guides you through the step-by-step configuration and validation of NSX-v for microsegmentation services. Microsegmentation makes the data center network more secure by isolating each related group of virtual machines onto a distinct logical network segment, allowing the administrator to firewall traffic traveling from one segment of the data center to another (east-west traffic). This limits attackers’ ability to move laterally in the data center.

VMware NSX uniquely makes microsegmentation scalable, operationally feasible, and cost-effective. This security service provided to applications is now agnostic to virtual network topology. The security configurations we explain in this document can be used to secure traffic among VMs on different L2 broadcast domains or to secure traffic within a L2 broadcast domain.

Microsegmentation is powered by the Distributed Firewall (DFW) component of NSX. DFW operates at the ESXi hypervisor kernel layer and processes packets at near line-rate speed. Each VM has its own firewall rules and context. Workload mobility (vMotion) is fully supported with DFW, and active connections remain intact during the move.

This paper will guide you through two microsegmentation use cases and highlight steps to implement
them in your own environment.

Use Case and Solution Scenarios

This document presents two solution scenarios that use east-west firewalling to handle the use case of
securing network traffic inside the data center. The solution scenarios are:

  • Scenario 1: Microsegmentation for a three-tier application using three different layer-2 logical segments (here implemented using NSX logical switches connected over VXLAN tunnels):

Scenario 1 Logical View.

Figure 1 – Scenario 1 Logical View.

In Scenario 1, there are two VMs per tier, and each tier hosts a dedicated function (WEB / APP / DB
services). Traffic protection is provided within the tier and between tiers. Logical switches are used to
group VMs of same function together.

  • Scenario 2: Microsegmentation for a three-tier application using a single layer-2 logical segment:

Scenario 2 Logical View.

Figure 2 – Scenario 2 Logical View.

In Scenario 2, all VMs are located on same tier. Traffic protection is provided within tier and per function (WEB/ APP/ DB services). Security Groups (SG) are used to logically group VMs of same function together.

For both Scenario 1 and Scenario 2, the following security policies are enforced:

Security Policy

Security Policy

For Scenario 1, a logical switch object is used for source and destination fields. For Scenario 2, a Service Composer / Security Group object is used for source and destination fields. By using these vCenterdefined objects, we optimize the number of needed firewall rules irrespective of number of VMs per tier (or per function).

NOTE: TCP port 1433 simulates the SQL service.

Physical Topology

Physical Topology

Figure 3 – Physical Topology.

Two ESXi hosts in the same cluster are used. Each host has following connectivity to the physical

  • one VLAN for management, vMotion, and storage. Communication between the ESXi host and the NSX Controllers also travels over this VLAN.
  • one VLAN for data traffic: VXLAN-tunneled, VM-to-VM data traffic uses this VLAN.


  • Web-01, app-01 and db-01 VMs are hosted on the first ESXi host.
  • Web-02, app-02 and db-02 VMs are hosted on the second ESXi host.

The purpose of this implementation is to demonstrate complete decoupling of the physical infrastructure from the logical functions such as logical network segments, logical distributed routing and DFW.
In other words, microsegmentation is a logical service offered to an application infrastructure irrespective of physical component. There is no dependency on where each VM is physically located.


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