Unlike the other versions of the VM-Series firewall, because both virtual wire interfaces (and subinterfaces) belong to the same zone, the VM-Series firewall for NSX uses dynamic address groups as the traffic segmentation mechanism. A security policy rule on the VM-Series firewall for NSX must have the same source and destination zone, therefore to implement different treatment of traffic, you use dynamic address groups as source or destination objects in security policy rules.

Dynamic address groups offer a way to automate the process of referencing source and/or destination addresses within security policies because IP addresses are constantly changing in a data center environment. Unlike static address objects that must be manually updated in configuration and committed whenever there is an address change (addition, deletion, or move), dynamic address groups automatically adapt to changes.

Any dynamic address groups created in a device group belonging to NSX configuration and configured with the match criterion

_nsx_

<dynamic address group name>

trigger the creation on corresponding security groups on the NSX Manager. In an ESXi cluster with multiple customers or tenants, the ability to filter security groups for a service profile (zone on Panorama) on the NSX Manager allows you to enforce policy when you have overlapping IP addresses across different security groups in your virtual environment.

If, for example, you have a multi-tier architecture for web applications, on Panorama you create three dynamic address groups for the WebFrontEnd servers, Application servers and the Database servers. When you commit these changes on Panorama, it triggers the creation of three corresponding security groups on NSX Manager.

On NSX Manager, you can then add guest VMs to the appropriate security groups. Then, in security policy you can use the dynamic address groups as source or destination objects, define the applications that are permitted to traverse these servers, and push the rules to the VM-Series firewalls.

Each time a guest is added or modified in the ESXi cluster or a security group is updated or created, the NSX Manager uses the PAN-OS REST-based XML API to update Panorama with the IP address, and the security group to which the guest belongs. To trace the flow of information, see Dynamic Address Groups—Information Relay from NSX Manager to Panorama.

When Panorama receives the API notification, it verifies/updates the IP address of each guest and the security group and the service profile to which that guest belongs. Then, Panorama pushes these real-time updates to all the firewalls that are included in the device group and notifies device groups in the service manager configuration on Panorama.

On each firewall, all policy rules that reference these dynamic address groups are updated at runtime. Because the firewall matches on the security group tag to determine the members of a dynamic address group, you do not need to modify or update the policy when you make changes in the virtual environment. The firewall matches the tags to find the current members of each dynamic address group and applies the security policy to the source/destination IP address that are included in the group.