Centos – Configure IPv6 – CentOS OVH – Can’t ping

centosipv6ovh

I can't ping my IPv6 from outside and inside of the server, i can't ping any IPv6. My IPv6 : 2001:41d0:2:XXXX::/64

I use CentOS 6.6 with a Xen Kernel that supports IPv6. My provider is OVH and i followed several guides : http://guide.ovh.com/Ipv4Ipv6 and http://www.cyberciti.biz/faq/rhel-re…configuration/ and here my config :

cat /etc/sysconfig/network

...
NETWORKING_IPV6=yes

cat /etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE=eth0
BOOTPROTO=static
...
IPV6INIT=yes
IPV6_AUTOCONF=no
IPV6ADDR="2001:41D0:2:xxxx::/64"
IPV6_DEFAULTGW="2001:41d0:2:xxff:ff:ff:ff:ff"

cat /etc/sysconfig/network-scripts/route6-eth0

...
net.ipv6.conf.all.autoconf = 0 
net.ipv6.conf.default.autoconf = 0 
net.ipv6.conf.eth0.autoconf = 0
net.ipv6.conf.all.accept_ra = 0 
net.ipv6.conf.default.accept_ra = 0 
net.ipv6.conf.eth0.accept_ra = 0
net.ipv6.conf.all.accept_redirects=0 
net.ipv6.conf.all.router_solicitations=1
net.ipv6.conf.default.proxy_ndp=1
net.ipv6.conf.all.proxy_ndp=1 
net.ipv6.conf.default.forwarding=1
net.ipv6.conf.all.forwarding = 1

Network restart : service network restart

i add a route : route -A inet6 add default gw 2001:41d0:2:xxff:ff:ff:ff:ff dev eth0

Ip6tables is disabled.

ifconfig -a

eth0      ...
          inet6 addr: 2001:41d0:2:xxxx::/64 Scope:Global
          inet6 addr: fe80::230:48ff:fefd:7a86/64 Scope:Link

traceroute ipv6.google.com

traceroute to ipv6.google.com (2a00:1450:4007:80d::200e), 30 hops max, 80 byte packetsping ipv6.
 1  2001:41d0:2:xxxx::)  3005.167 ms !H  3005.118 ms !H  3005.089 ms !H

ping ipv6.google.com

ping: unknown host ipv6.google.com

Ping from an IPv6 failed too.

I change IPv6 like that : 2001:41d0:2:XXXX::1234/64

I have one file for IPv6 routes :

cat /etc/sysconfig/network-scripts/route6-eth0

2001:41D0:2:xxff:ff:ff:ff:ff dev eth0
default via 2001:41D0:2:xxff:ff:ff:ff:ff

I restarted the network service and i get this warning message :

service network restart

Shutting down interface eth0:                              [  OK  ]
Shutting down loopback interface:                          [  OK  ]
Bringing up loopback interface:                            [  OK  ]

Global IPv6 forwarding is disabled in configuration, but not currently disabled
in kernel

Please restart network with '/sbin/service network restart'

WARN : [ipv6_add_route] 'No route to host' adding route '::/0' via gateway ' 2001:41d0:2:xxff:ff:ff:ff:ff' through device ''
[ OK ]

ping6 2001:41d0:2:xxff:ff:ff:ff:ff

PING 2001:41d0:2:xxff:ff:ff:ff:ff(2001:41d0:2:xxff:ff:ff:ff:ff) 56 data bytes

From 2001:41d0:2:xxxx::1234 icmp_seq=1 Destination unreachable: Address unreachable

Best Answer

The address 2001:41d0:2:XXXX::/64 has an all-zero host part. Try assigning a proper address, eg. 2001:41d0:2:XXXX::YYYY/64.

Before you try pinging a host on the Internet like ipv6.google.com, check if you can ping the default gateway by its numeric address 2001:41d0:2:xxff:ff:ff:ff:ff.

Also check if XXXX == xxff in the above addresses. Otherwise your CentOS machine won't be able to reach the default gateway, at least not without the additional route command given on the OVH guide page.

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