The KNX system generally has two types of communication on Ethernet basis: KNXnet/IP routing and KNXnet/IP tunneling, both use the UDP protocol. Tunneling has the goal of accessing the KNX bus via Ethernet, e.g. for commissioning, error diagnostics or visualization. A point-to-point connection is established between a PC and the IP router. This can be done locally over LAN or over the Internet.
The following document explains the settings for the tunneling servers describing step by step how to use them:KNX, Remote Access