1. An ingress-session-based authorization and access control method in a data processing system to control access from an initiator-host (IH) to objects Target 1, Target 2 ) on a target host (TH) comprising the steps of: (i) receiving an access-request, preferably a request-message (M 1 ), originally coming from the initiator-host (IH), that references an object (Target 1, Target 2 ) on the target host (TH) to access, (ii) assigning the access-request (M 1 ) to an ingress-session and selecting a session-context (SC-U, SC-W, SC-Y) belonging to that ingress-session, (iii) checking whether the access to the referenced object Target 1, Target 2 ) is authorized in the selected session-context (SC-U, SC-W, SC-Y) or not, and (iv) denying the access to the referenced object Target 1, Target 2 ) if the access to said object on the target host (TH) is not authorized in the selected session-context (SC-U, SC-W, SC-Y), (v) granting the access to the referenced object Target 1, Target 2 ) if the access to said object on the target host (TH) is allowed in the selected session-context. (SC-U, SC-W, SC-Y) wherein references to objects (Target 1, Target 2 ) on the target host (TH) were handed over to the initiator-host (IH) as a response to an access-request already granted and wherein the object the reference is handed over for is authorized for access under the handed over reference in that session-context (SC-U, SC-W, SC-Y) the already granted access-request is assigned to.