I recently added an IPv6 address to a vserver running BIND. But BIND doesn't mind. Using "strace -s 1500 -o /tmp/trc -f named -d 10 -p 54 -f -g" I found out it opened /proc/net/if_inet6 and just ignored IPv6 afterwards. (using port 54 here to not interfere with the productive dns) So I added interface lo - ::1 - /128 in /etc/vservers . Now I get 29-Oct-2016 10:49:06.912 using default UDP/IPv4 port range: [1024, 65535] 29-Oct-2016 10:49:06.912 using default UDP/IPv6 port range: [1024, 65535] 29-Oct-2016 10:49:06.913 listening on IPv4 interface lo, 127.0.0.1#54 29-Oct-2016 10:49:06.913 listening on IPv4 interface eth0:0, 212.9.165.46#54 so I'm missing something like listening on IPv6 interface eth0<*>, 2001:14b0:203:4000::6e73#54 Other stuff: BIND compiled with "--enable-ipv6" "listen-on-v6 { any; };" is set, changing it to "listen-on-v6 { 2001:14b0:203:4000::6e73; };" does not change anything. /etc/default/bind9 is OPTIONS="" netstat -tulpen Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State User Inode PID/Program name tcp 0 0 212.9.165.46:53 0.0.0.0:* LISTEN 0 13771626 21924/named tcp 0 0 127.0.0.1:53 0.0.0.0:* LISTEN 0 13771624 21924/named tcp 0 0 212.9.165.46:54 0.0.0.0:* LISTEN 0 13932904 22117/named tcp 0 0 127.0.0.1:54 0.0.0.0:* LISTEN 0 13932902 22117/named tcp 0 0 127.0.0.1:953 0.0.0.0:* LISTEN 0 13771627 21924/named tcp6 0 0 ::1:953 :::* LISTEN 0 13771628 21924/named udp 0 0 212.9.165.46:53 0.0.0.0:* 0 13771625 21924/named udp 0 0 127.0.0.1:53 0.0.0.0:* 0 13771623 21924/named udp 0 0 212.9.165.46:54 0.0.0.0:* 0 13932903 22117/named udp 0 0 127.0.0.1:54 0.0.0.0:* 0 13932901 22117/named udp6 0 0 :::35767 :::* 0 13933799 22117/named Inside the vserver I can set up echo "ACK" | nc -6 -l -p 54 -v and run nc 2001:14b0:203:4000::6e73 54 from - the vserver itself - the vhost - a completely different piece of hardware and get my "ACK". The listener can't be launched on port 53 as long as BIND runs: nc: Address already in use which is quite fine and indicates the port is held open by BIND. I can run (vserver): nc -6 -l -p 53 -u -v and try from outside dig @2001:14b0:203:4000::6e73 soa uoduouvfdouvdf +short with the result of Listening on [:::] (family 10, port 53) �9 uoduouvfdouvdf)�9 uoduouvfdouvdf)�9 uoduouvfdouvdf) so, the communication on IPv6 port 53/udp just works fine. At last I tried strace -s 200 -f named -p 54 -f -g and dig @2001:14b0:203:4000::6e73 soa uoduouvfdouvdf +short -p 54 result: absolutely no reaction on the BIND side. -- LiHAS - Adrian Reyer - Hessenwiesenstraße 10 - D-70565 Stuttgart Fon: +49 (7 11) 78 28 50 90 - Fax: +49 (7 11) 78 28 50 91 Mail: lihas@lihas.de - Web: http://lihas.de Linux, Netzwerke, Consulting & Support - USt-ID: DE 227 816 626 Stuttgart