Along with a Virtual device extension, each NiagaraStation has an associated Boolean property, “Virtuals Enabled”, found near the bottom of any NiagaraStation’s property sheet (Figure 122).

This property must be true before Niagara virtual components for this station can be accessed. However, it defaults to false as a security measure, as when initially enabled, all components in the remote station will be accessible to any user with permissions on this NiagaraStation’s Virtual gateway.

For example, any user with admin-level permissions on the gateway will be able to view all Users in the remote station’s UserService, simply by expanding the property sheet of the virtual component for the UserService. Or, such a user will be able to expand the station’s PlatformServices virtual component, and have access to critical properties or child services (including an action to restart station/reboot host)!

Therefore, before enabling any Niagara Virtual gateway, it is recommended to restrict user access to it, (assign it to a restricted category). Then, on Niagara virtual components under that gateway, assign appropriate category(ies)—before re-assigning less restrictive category(ies) to the parent gateway.

Persisted category assignments for individual virtual components is an important feature. Originally, only the persisted parent virtual gateway component could be assigned to one or more categories—with all child virtual components inheriting those categories. Now with this feature, categories assigned to active virtual components are safely maintained even after virtuals are removed from the station’s memory cache.

Assign categories to Niagara virtual components using “normal component” methods, that is either by

Be careful to Save after making any needed category changes to the Niagara Virtual gateway or virtual components. For more information about station security and categories, refer to the sections “About Security” and “CategoryService” in the NiagaraAX User Guide.