Hello, today hostname nscache.eu.sixxs.org has 4 IPv6 addresses: host nscache.eu.sixxs.org nscache.eu.sixxs.org is an alias for ipv6.nginx.sixxs.net. ipv6.nginx.sixxs.net has IPv6 address 2001:960:800::2 ipv6.nginx.sixxs.net has IPv6 address 2001:1af8:1:f006::6 ipv6.nginx.sixxs.net has IPv6 address 2001:7b8:3:4f:202:b3ff:fe46:bec ipv6.nginx.sixxs.net has IPv6 address 2001:838:2:1::30:67 But these two 2001:960:800::2 ( broker04.ams.nl.sixxs.net ) 2001:838:2:1::30:67 ( gatey.sixxs.net ) are not responding on DNS queries: dig @2001:960:800::2 www.google.com AAAA ; <<>> DiG 9.7.0-P1 <<>> @2001:960:800::2 www.google.com AAAA ; (1 server found) ;; global options: +cmd ;; connection timed out; no servers could be reached dig @2001:838:2:1::30:6 www.google.com AAAA ; <<>> DiG 9.7.0-P1 <<>> @2001:838:2:1::30:6 www.google.com AAAA ; (1 server found) ;; global options: +cmd ;; connection timed out; no servers could be reached tcpdump: 10:26:38.362268 IP6 2001:6a0:13e:7::2.45300 > 2001:960:800::2.53: 52248+[|domain] 10:26:38.431978 IP6 2001:960:800::2 > 2001:6a0:13e:7::2: ICMP6, destination unreachable[|icmp6] The other two: 2001:1af8:1:f006::6 ( no rev-dns ) 2001:7b8:3:4f:202:b3ff:fe46:bec ( nlede01.sixxs.net ) Works perfectly. Do you observe the same? May be that those DNS servers which are not responding on my queries need to be asked for permission to send queries ? If it is not only my problem I consider sending this topic to ticket system or sixxs staff. Lukasz