Zorp is capable of stacking, that is, handing over parts of the traffic to other modules for further inspection (e.g., to other proxies to inspect embedded protocols, to content vectoring modules for virus filtering, etc.). The Stack module defines the classes required for this functionality.

Stacking in Zorp services is performed using StackingProvider policies, which reference the host that performs the stacked operations using the RemoteStackingBackend class.