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Follow the Setup of 6to4 tunnel guide, I want to test ipv6 connectivity, but I cannot ping6 to ipv6.google.com.

Details below:

# traceroute 192.88.99.1
traceroute to 192.88.99.1 (192.88.99.1), 30 hops max, 40 byte packets
 1  static.vdc.vn (123.30.53.1)  1.514 ms  2.622 ms  3.760 ms
 2  static.vdc.vn (123.30.63.117)  0.608 ms  0.696 ms  0.735 ms
 3  static.vdc.vn (123.30.63.101)  0.474 ms  0.477 ms  0.506 ms
 4  203.162.231.214 (203.162.231.214)  11.327 ms  11.320 ms  11.312 ms
 5  static.vdc.vn (222.255.165.34)  11.546 ms  11.684 ms  11.768 ms
 6  203.162.217.26 (203.162.217.26)  42.460 ms  42.424 ms  42.401 ms
 7  218.188.104.173 (218.188.104.173)  42.489 ms  42.462 ms  42.415 ms
 8  218.189.5.10 (218.189.5.10)  42.613 ms 218.189.5.42 (218.189.5.42)  42.273 ms  42.300 ms
 9  d1-26-224-143-118-on-nets.com (118.143.224.26)  205.752 ms d1-18-224-143-118-on-nets.com (118.143.224.18)  207.130 ms d1-14-224-143-118-on-nets.com (118.143.224.14)  206.970 ms
10  218.189.5.150 (218.189.5.150)  207.456 ms  206.349 ms  206.941 ms
11  * * *
12  10gigabitethernet2-1.core1.lax1.he.net (72.52.92.121)  214.087 ms  214.426 ms  214.818 ms
13  192.88.99.1 (192.88.99.1)  207.215 ms  199.270 ms  209.391 ms

# ifconfig tun6to4
tun6to4   Link encap:IPv6-in-IPv4  
          inet6 addr: 2002:x:x::/16 Scope:Global
          inet6 addr: ::x.x.x.x/128 Scope:Compat
          UP RUNNING NOARP  MTU:1480  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:11 dropped:0 overruns:0 carrier:11
          collisions:0 txqueuelen:0 
          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)

# iptunnel 
sit0: ipv6/ip  remote any  local any  ttl 64  nopmtudisc
tun6to4: ipv6/ip  remote any  local x.x.x.x  ttl 64 

# ip -6 route show
::/96 via :: dev tun6to4  metric 256  expires 21332777sec mtu 1480 advmss 1420 hoplimit 4294967295
2002::/16 dev tun6to4  metric 256  expires 21332794sec mtu 1480 advmss 1420 hoplimit 4294967295
fe80::/64 dev eth0  metric 256  expires 15674592sec mtu 1500 advmss 1440 hoplimit 4294967295
fe80::/64 dev eth1  metric 256  expires 15674597sec mtu 1500 advmss 1440 hoplimit 4294967295
fe80::/64 dev tun6to4  metric 256  expires 21332794sec mtu 1480 advmss 1420 hoplimit 4294967295
default via ::192.88.99.1 dev tun6to4  metric 1  expires 21332861sec mtu 1480 advmss 1420 hoplimit 4294967295

# ping6 -n -c 4 ipv6.google.com
PING ipv6.google.com(2404:6800:8005::68) 56 data bytes
From 2002:x:x:: icmp_seq=0 Destination unreachable: Address unreachable
From 2002:x:x:: icmp_seq=1 Destination unreachable: Address unreachable
From 2002:x:x:: icmp_seq=2 Destination unreachable: Address unreachable
From 2002:x:x:: icmp_seq=3 Destination unreachable: Address unreachable

--- ipv6.google.com ping statistics ---
4 packets transmitted, 0 received, +4 errors, 100% packet loss, time 2999ms

What is my problem?

Thanks,

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2 Answers 2

The 6to4 mechanism is very fragile and is not recommanded this days.

As you don't choose the exit relay you can't change it if it is dead or misconfigured. It may be your problem (the relay is reachable in v4 but you can't be sure that the 6to4 mechanism is up on the host) but you can't use another exit node to check ...

There is an other possibility of failure if a firewall on the path to the 6to4 relay is filtering the protocol 41. In this case you won't be able to setup a 6in4 tunnel either.

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I added a default route with ip -6 route add ::/0 via ::192.88.99.1 dev tun6to4 metric 1. You can see this line from my first post: default via ::192.88.99.1 dev tun6to4 metric 1. I also tried with 2000::/3, but it still didn't work. I don't have my own v6 gateway, does 192.88.99.1 still work? –  quanta Feb 11 '11 at 11:17
    
I am sorry, I thought that you where trying to setup a 6in4 tunnel with some tunnel broker like SiXX or HE. 6to4 is mostly abandonned this days because you have no control on the exit end and if it is broken you cannot change to another. –  jon_d Feb 11 '11 at 13:58
    
I have written a new answer correlated to your question this time. –  jon_d Feb 11 '11 at 14:30
up vote 1 down vote accepted

Sorry, my 'typo' mistake. My public IPv4 is: x.x.x.127 but I typed:

ip tunnel add tun6to4 mode sit ttl 64 remote any local x.x.x.27

Now, I can ping6 and traceroute6 to ipv6.google.com:

# ping6 -n -c 4 ipv6.google.com
PING ipv6.google.com(2404:6800:8005::63) 56 data bytes
64 bytes from 2404:6800:8005::63: icmp_seq=0 ttl=58 time=217 ms
64 bytes from 2404:6800:8005::63: icmp_seq=1 ttl=58 time=217 ms
64 bytes from 2404:6800:8005::63: icmp_seq=2 ttl=58 time=217 ms
64 bytes from 2404:6800:8005::63: icmp_seq=3 ttl=58 time=217 ms

--- ipv6.google.com ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3001ms
rtt min/avg/max/mdev = 217.258/217.366/217.489/0.577 ms, pipe 2

# traceroute6 ipv6.google.com
traceroute to ipv6.google.com (2404:6800:8005::63), 30 hops max, 40 byte packets
 1  2002:c058:6301::1 (2002:c058:6301::1)  199.193 ms  199.169 ms  199.153 ms
 2  gige-g4-12.core1.lax1.he.net (2001:470:0:14e::1)  199.279 ms  199.268 ms  199.403 ms
 3  PR01.LAX03.google.com (2001:504:0:3:0:1:5169:1)  199.633 ms  199.620 ms  199.755 ms
 4  2001:4860::1:0:991 (2001:4860::1:0:991)  242.128 ms 2001:4860::1:0:607 (2001:4860::1:0:607)  204.765 ms 2001:4860::1:0:991 (2001:4860::1:0:991)  204.753 ms
 5  2001:4860::1:0:7ea (2001:4860::1:0:7ea)  235.740 ms  243.709 ms 2001:4860::1:0:21 (2001:4860::1:0:21)  233.959 ms
 6  2001:4860::1:0:75 (2001:4860::1:0:75)  215.427 ms  233.980 ms 2001:4860::1:0:47 (2001:4860::1:0:47)  214.836 ms
 7  2001:4860::1:0:1063 (2001:4860::1:0:1063)  242.264 ms 2001:4860::1:0:16 (2001:4860::1:0:16)  216.691 ms 2001:4860::1:0:1063 (2001:4860::1:0:1063)  242.287 ms
 8  2001:4860::2:0:119c (2001:4860::2:0:119c)  217.665 ms 2001:4860::2:0:119b (2001:4860::2:0:119b)  217.597 ms  217.436 ms
 9  * 2001:4860:0:1::e1 (2001:4860:0:1::e1)  221.650 ms *
10  2404:6800:8005::63 (2404:6800:8005::63)  216.882 ms  216.917 ms  216.897 ms

I will try to configure 6in4 tunnel to see what's different from 6to4 tunnel.

Thank you for your info.

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