centos: ping6 알 수 없는 호스트

Centos 6.5, ipv6가 활성화되어 있고 (부분적으로) 작동합니다. "ping6 bin6.it"을 실행하려고 하면 "알 수 없는 호스트" 오류가 반환됩니다.

[root@centos ~]# ping6 bin6.it
unknown host

호스트는 다음을 해결할 수 있습니다.

[root@centos ~]# host bin6.it
bin6.it has IPv6 address 2607:fd50:1:91b0::b146:11
bin6.it mail is handled by 20 mx02.puttynuts.com.
bin6.it mail is handled by 10 mx01.puttynuts.com.

IP 주소에 대한 ping도 정상적으로 작동합니다.

[root@centos ~]# ping6 2607:fd50:1:91b0::b146:11
PING 2607:fd50:1:91b0::b146:11(2607:fd50:1:91b0::b146:11) 56 data bytes
64 bytes from 2607:fd50:1:91b0::b146:11: icmp_seq=1 ttl=47 time=273 ms
64 bytes from 2607:fd50:1:91b0::b146:11: icmp_seq=2 ttl=47 time=268 ms
64 bytes from 2607:fd50:1:91b0::b146:11: icmp_seq=3 ttl=47 time=268 ms
64 bytes from 2607:fd50:1:91b0::b146:11: icmp_seq=4 ttl=47 time=268 ms
--- 2607:fd50:1:91b0::b146:11 ping statistics ---
5 packets transmitted, 4 received, 20% packet loss, time 4026ms
rtt min/avg/max/mdev = 268.293/269.715/273.367/2.215 ms

뭐가 문제 야?

요청에 의해 추가됨:

[root@centos ~]# cat /etc/resolv.conf
# Generated by NetworkManager
search mydomain.com
nameserver 192.168.5.34

[root@centos ~]# grep hosts /etc/nsswitch.conf
#hosts:     db files nisplus nis dns
#hosts:      files mdns4_minimal [NOTFOUND=return] dns
#hosts:      dns files mdns4_minimal
hosts:      files dns mdns4