IPv6 web server unreachable

Question

I've bought a new dedicated server with 2 IPv4 addresses and a /56 IPv6 subnet. When I ping to my domain names on the dedicated server I get a message back. But when I ping from outside nothing happens.

So I went to test things out through IPv6.nl etc and everything's fine except the connection to my web server. The test can't reach my server. I've tried to open the ports of my firewall but it doesn't seem to work.

My hostname is cp.hshweb.eu running on a dedicated server (CentOS6.6) with Odin plesk installed for the virtual hosts. What steps can I do and try to get my we server accessible from outside using IPv6?

When I reset networking I get this message:

[root@cp network-scripts]# service network restart
Shutting down interface eth0:                              [  OK  ]
Shutting down loopback interface:                          [  OK  ]
Bringing up loopback interface:                            [  OK  ]
Bringing up interface eth0:
Determining IP information for eth0... done.
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
Determining if ip address 85.214.148.249 is already in use for device eth0...
                                                           [  OK  ]

ip addr show gives this:

[root@cp ~]# ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 40:61:86:ee:be:3f brd ff:ff:ff:ff:ff:ff
    inet 85.214.208.177/32 brd 85.214.208.177 scope global eth0
    inet 85.214.148.249/32 brd 85.214.148.249 scope global eth0:1
    inet6 2a01:238:4317:d800:cafe:dead:beef:0/128 scope global
       valid_lft forever preferred_lft forever
    inet6 2a01:238:4317:d800::feed/128 scope global
       valid_lft forever preferred_lft forever
    inet6 2a01:238:4317:d800::/56 scope global
       valid_lft forever preferred_lft forever
    inet6 2a01:238:4317:d800:0:bad:a55:cafe/128 scope global
       valid_lft forever preferred_lft forever
    inet6 2a01:238:4317:d800:d108:898c:628f:a199/128 scope global
       valid_lft forever preferred_lft forever
    inet6 fe80::4261:86ff:feee:be3f/64 scope link
       valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 1000
    link/ether 40:61:86:ee:be:40 brd ff:ff:ff:ff:ff:ff

This is my ifcfg-eth0 file:

DEVICE="eth0"
BOOTPROTO="dhcp"
DHCPV6C="no"
IPV6INIT="yes"
IPV6_AUTOCONF="no"
IPV6_ROUTER="yes"
NM_CONTROLLED="no"
ONBOOT="yes"
HWADDR=40:61:86:EE:BE:3F
IPV6ADDR="2a01:238:4317:d800:d108:898c:628f:a199/128"
IPV6ADDR_SECONDARIES="2a01:238:4317:d800:0:bad:a55:cafe/128 2a01:238:4317:d800::/56 2a01:238:4317:d800::feed/128 2a01:238:4317:d800:cafe:dead:beef:0/128 2a01:238:4317:d800:d108:898c:628f:a199/128 2a01:238:4317:d800::feed/128 2a01:238:4317:d800:0:bad:a55:cafe/128 2a01:238:4317:d800:cafe:dead:beef:0/128 2a01:238:4317:d800:d108:898c:628f:a199/128 2a01:238:4317:d800::/0"
IPV6_DEFAULTGW=2a01:238:4317:d800::1
IPV6FORWARDING=yes

And my network configuration is:

HOSTNAME=cp.domain.tld
NETWORKING=yes
NETWORKING_IPV6=yes
IPV6_DEFAULTDEV=eth0
IPV6FORWARDING=yes
IPV6_AUTOCONF=no
IPV6_AUTOTUNNEL=no
IPV6_DEFAULTGW=2a01:238:4317:d800::1

ip -6 route:

[root@cp ~]# ip -6 route
::/96 via :: dev sit0  metric 256  mtu 1480 advmss 1420 hoplimit 4294967295
unreachable ::/96 dev lo  metric 1024  error -101 mtu 65536 advmss 65476 hoplimit 4294967295
unreachable ::ffff:0.0.0.0/96 dev lo  metric 1024  error -101 mtu 65536 advmss 65476 hoplimit 4294967295
unreachable 2002:a00::/24 dev lo  metric 1024  error -101 mtu 65536 advmss 65476 hoplimit 4294967295
unreachable 2002:7f00::/24 dev lo  metric 1024  error -101 mtu 65536 advmss 65476 hoplimit 4294967295
unreachable 2002:a9fe::/32 dev lo  metric 1024  error -101 mtu 65536 advmss 65476 hoplimit 4294967295
unreachable 2002:ac10::/28 dev lo  metric 1024  error -101 mtu 65536 advmss 65476 hoplimit 4294967295
unreachable 2002:c0a8::/32 dev lo  metric 1024  error -101 mtu 65536 advmss 65476 hoplimit 4294967295
unreachable 2002:e000::/19 dev lo  metric 1024  error -101 mtu 65536 advmss 65476 hoplimit 4294967295
2a01:238:4317:d800::feed dev eth0  proto kernel  metric 256  mtu 1500 advmss 1440 hoplimit 4294967295
2a01:238:4317:d800:0:bad:a55:cafe dev eth0  proto kernel  metric 256  mtu 1500 advmss 1440 hoplimit 4294967295
2a01:238:4317:d800:cafe:dead:beef:0 dev eth0  proto kernel  metric 256  mtu 1500 advmss 1440 hoplimit 4294967295
2a01:238:4317:d800:d108:898c:628f:a199 dev eth0  proto kernel  metric 256  mtu 1500 advmss 1440 hoplimit 4294967295
2a01:238:4317:d800::/56 dev eth0  proto kernel  metric 256  mtu 1500 advmss 1440 hoplimit 4294967295
unreachable 3ffe:ffff::/32 dev lo  metric 1024  error -101 mtu 65536 advmss 65476 hoplimit 4294967295
fe80::/64 dev eth0  proto kernel  metric 256  mtu 1500 advmss 1440 hoplimit 4294967295
default via 2a01:238:4317:d800::1 dev eth0  metric 1  mtu 1500 advmss 1440 hoplimit 4294967295

Ping to google returns:

[root@cp ~]# ping6 ipv6.google.com -c 6
PING ipv6.google.com(ham02s13-in-x07.1e100.net) 56 data bytes
From 2a01:238:4317:d800:cafe:dead:beef:0 icmp_seq=2 Destination unreachable: Address unreachable
From 2a01:238:4317:d800:cafe:dead:beef:0 icmp_seq=3 Destination unreachable: Address unreachable
From 2a01:238:4317:d800:cafe:dead:beef:0 icmp_seq=4 Destination unreachable: Address unreachable
From 2a01:238:4317:d800:cafe:dead:beef:0 icmp_seq=5 Destination unreachable: Address unreachable
From 2a01:238:4317:d800:cafe:dead:beef:0 icmp_seq=6 Destination unreachable: Address unreachable

--- ipv6.google.com ping statistics ---
6 packets transmitted, 0 received, +5 errors, 100% packet loss, time 15001ms

Falcon Momot · Accepted Answer · 2015-06-23T23:24:38.760

The best thing to do is to check whether you can talk to IPv6 sites such as ipv6.google.com from your server. This will help you determine whether the problem is your local configuration, or your IPv6 connection - if you can ping distant IPv6 sites, the problem might be your firewall or HTTP daemon, but if you can't, it's the connection.

You have a routeable address. So, it might be a problem with your host or your transit provider, or a routing issue elsewhere.

For what it's worth, at the time of writing, I can't ping your server from my HE.net tunnel.

Given the updated information, there's something else I remember that I left out. If you've configured the address explicitly (i.e. it wasn't automatically configured by RA), which it looks like since the address is a mnemonic one and I see it in your static configuration, it might just not know its gateway configuration. The way to configure this depends on your distribution, but it should be right next to where you configured the IP.

For yours, you simply need to add one line to ifcfg-eth0:

IPV6_DEFAULTGW=2a01:238:4317:d800::1

Replace that address with the correct gateway if it is something else. Check that you can use ping6 to ping that gateway, too.

Bizzarely, it looks like your distribution doesn't add a local network route for your configured static addresses either (and so, it can't find the gateway). So, you'll need to add it in /etc/sysconfig/network-scripts/route6-eth0:

2a01:238:4317:d800::/56 dev eth0

IPv6 web server unreachable

1 Answers1