IPx/S 3.1.1: Do the tunnel connections shown in the Connection Manager always correspond with the project?
The physical addresses of the tunnel connections can differ from the project. They can be changed at any time using the ETS. It should be noted that after a router download, all IP settings of the project currently in use will always be adopted: DHCP, fixed IP addresses and tunnel connections.
Also see: http://new.abb.com/low-voltage/products/intelligent-building-systems/abb-i-bus-knx/new-abb-i-bus-knx-ip-devices