By accident one of my DCs has IPv6 enabled, contrary to the other two DCs. I don?t remember whether I turned IPv6 on or off explicitly on any of these, but anyway? I also run a monitoring tool that checks whether ?published services? are available, and it performs checking for any IP-Address known. Now the tool thus tested the DC with IPv6 enabled whether it responds to DNS queries on IPv6, and it doesn?t, netstat -a -n | grep LISTEN | grep ":53" shows tcp and no tcp6. I didn?t find a configuration option to enable/disable IPv6, thus I am wondering whether this is by design or just a leftover. Or did I miss some documentation? Thanks, Joachim