A first node receives data packets of a flow and forwards the data packets of the flow to a second node. The first node takes a first decision whether to perform inspection of a payload section of at least one data packet of the flow at the first node and indicate a result of the first decision to the second node. The second node receives the data packets of the flow from the first node. On the basis of the result of the first decision indicated by the first node, the second node takes a second decision whether to perform inspection of a payload section of at least one data packet of the flow at the second node.