Dear Geert, Thank you four instructions. > * install my favorite network sniffer ( e.g. tcpdump, tshark, wireshark ) I used dhcpdump. > * analyze the network capture, filter out the MAC-adress of 10.0.1.1 The discovered address (70:56:81:c4:f8:cd) is from the range of Apple Inc. (and not VMWare ^^) I have an idea... Will come back the next days (as I'm not on site). Cheers, Oliver