For generating ItemIDs, the Proxy uses Namespace Indices. To assure that Clients can persist these ItemIDs, the Namespace Indices must never change. To accomplish this the Proxy has to persist its Namespace Table and only append entries but never change existing ones.
The Proxy also has to provide a translation from the current Namespace Table in the Server to the persisted Namespace Table.
If you move or copy the Proxy to another machine, the Namespace Table has to be copied to this machine as well.