The routing information is extracted from a received message at a border between a first network and a second network, and at least one invalid entry is added to first-network entries of the routing information which relate to a routing path of the message within the first network. The at least one invalid entry and the first-network entries are encrypted by using an own token at least for each of the first-network entries. As an alternative, a tokenized second-network entry extracted from the routing information and relating to the routing path of the message within the second network is decrypted, and its content is reversed. In both cases, the routing information is replaced by the processed routing information and the message is forwarded to the second network. This allows to preserve the order of routing entries and to hide the amount of switches that have been traversed in the home network.