Testing Connections

Linux

On Linux, log into your instance and execute the following command:

$ ping6 2001:4860:4860::8888
PING 2001:4860:4860::8888(2001:4860:4860::8888) 56 data bytes
64 bytes from 2001:4860:4860::8888: icmp_seq=1 ttl=51 time=4.60 ms
64 bytes from 2001:4860:4860::8888: icmp_seq=2 ttl=51 time=4.08 ms
64 bytes from 2001:4860:4860::8888: icmp_seq=3 ttl=51 time=4.13 ms
64 bytes from 2001:4860:4860::8888: icmp_seq=4 ttl=51 time=4.12 ms
^C
--- 2001:4860:4860::8888 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3004ms
rtt min/avg/max/mdev = 4.085/4.237/4.607/0.214 ms

If you get an error, check if the IPv6 address is correctly assigned on the first interface:

$ ip -6 a l dev eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 1000
    inet6 2a04:c43:c00:12f:491:58ff:fe00:79/64 scope global mngtmpaddr dynamic
       valid_lft 86360sec preferred_lft 14360sec
    inet6 fe80::480:58ff:fe00:79/64 scope link
       valid_lft forever preferred_lft forever

In addition to the fe80:: address prefix, you should get an address starting with 2a04::. If you do not have the fe80:: address prefix, IPv6 is disabled on your system. You can enable it with:

$ sysctl -w net.ipv6.conf.all.disable_ipv6=0`

If you do not have the 2a04:: address prefix, the auto-configuration mechanism failed. This might be because of a locally configured firewall, or because IPv6 auto-configuration has been disabled. You can enable IPv6 auto-configuration with:

$ sysctl net.ipv6.conf.eth0.autoconf=1

If the addresses are present, check if:

you do not have a local firewall (check ip6tables-save),
you are not using egress rules in your security groups, and
you do not use privacy extensions (check sysctl net.ipv6.conf.eth0.use_tempaddr, it should be 0).

Windows

On Windows, you need to disable privacy extensions. You can disable privacy extensions by issuing the following commands in an administrative PowerShell session:

PS> Set-NetIPv6Protocol -RandomizeIdentifiers Disabled
PS> Set-NetIPv6Protocol -UseTemporaryAddresses Disabled

Then, you can test with ping6:

PS> ping6 2001:4860:4860::8888

Pinging 2001:4860:4860::8888 with 32 bytes of data:
Reply from 2001:4860:4860::8888: time<1ms
Reply from 2001:4860:4860::8888: time<1ms
Reply from 2001:4860:4860::8888: time=1ms
Reply from 2001:4860:4860::8888: time=1ms

Ping statistics for 2001:4860:4860::8888:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum = 1ms, Average = 0ms

If this does not work, use ipconfig /all to check if you have an IPv6 address:

PS> ipconfig /all
[…]
Ethernet adapter Ethernet:

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Red Hat VirtIO Ethernet Adapter
   Physical Address. . . . . . . . . : 06-6B-EA-00-00-36
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   IPv6 Address. . . . . . . . . . . : 2a04:c46:c00:12f:46b:eaff:fe00:36(Preferred)
   Link-local IPv6 Address . . . . . : fe80::46b:eaff:fe00:36%5(Preferred)
   IPv4 Address. . . . . . . . . . . : 89.145.160.49(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.252.0
   Lease Obtained. . . . . . . . . . : mardi, 17 avril 2018 14:10:14
   Lease Expires . . . . . . . . . . : vendredi, 24 mai 2154 20:45:03
   Default Gateway . . . . . . . . . : fe80::fc6b:eaff:fe00:36%5
                                       89.145.160.1
   DHCP Server . . . . . . . . . . . : 89.145.160.1
   DHCPv6 IAID . . . . . . . . . . . : 55727104
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-22-67-9C-42-06-6B-EA-00-00-36
   DNS Servers . . . . . . . . . . . : 89.145.160.136
                                       89.145.161.109
                                       185.150.8.225
   NetBIOS over Tcpip. . . . . . . . : Enabled

Also check if you got a default route:

PS> route print ::/0
[…]
IPv6 Route Table
===========================================================================
Active Routes:
 If Metric Network Destination      Gateway
  5    271 ::/0                     fe80::fc6b:eaff:fe00:36
===========================================================================
Persistent Routes:
  None

OpenBSD

On OpenBSD, you need to disable Semantically Opaque Interface Identifiers and privacy extensions. Add the following lines in /etc/hostname.vio0:

-soii
-autoconfprivacy

As of OpenBSD version 6.9 autoconfprivacy option has been deprecated and replaced by temporary. Make sure you specify inet6 autoconf options in /etc/hostname.vio0 in a single line:

$ inet6 autoconf -soii -temporary

Then, use sh /etc/netstart vio0 to reload the configuration. You can test if it works correctly with ping6:

$ ping6 2001:4860:4860::8888
PING 2001:4860:4860::8888 (2001:4860:4860::8888): 56 data bytes
64 bytes from 2001:4860:4860::8888: icmp_seq=0 hlim=61 time=1.296 ms
64 bytes from 2001:4860:4860::8888: icmp_seq=1 hlim=61 time=1.294 ms
64 bytes from 2001:4860:4860::8888: icmp_seq=2 hlim=61 time=1.218 ms
64 bytes from 2001:4860:4860::8888: icmp_seq=3 hlim=61 time=1.171 ms
64 bytes from 2001:4860:4860::8888: icmp_seq=4 hlim=61 time=1.345 ms
64 bytes from 2001:4860:4860::8888: icmp_seq=5 hlim=61 time=1.117 ms
^C
--- 2001:4860:4860::8888 ping statistics ---
6 packets transmitted, 6 packets received, 0.0% packet loss
round-trip min/avg/max/std-dev = 1.117/1.240/1.345/0.079 ms

If this does not work, check that you got an IPv6 with ifconfig:

$ ifconfig vio0
vio0: flags=648843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST,INET6_NOPRIVACY,AUTOCONF6,INET6_NOSOII> mtu 1500
        lladdr 06:6b:ea:00:00:36
        index 1 priority 0 llprio 3
        groups: egress
        media: Ethernet autoselect
        status: active
        inet 89.145.160.49 netmask 0xfffffc00 broadcast 89.145.163.255
        inet6 fe80::46b:eaff:fe00:36%vio0 prefixlen 64 scopeid 0x1
        inet6 2a04:c46:c00:12f:46b:eaff:fe00:36 prefixlen 64 autoconf pltime 14350 vltime 86350

Also, check if you got the default gateway:

$ route -n show | grep default | tail -1
default   fe80::fc6b:eaff:fe00:36%vio0   UGS        0        3     -    56 vio0

Fedora CoreOS

On Fedora CoreOS (FCOS), Network manager default configuration is set to stable-privacy. Eui64 mode is required to get IPv6 operational. It can be switched using the following command:

$ nmcli connection modify 'Wired connection 1' ipv6.addr-gen-mode default-or-eui64

A reboot is required for the change to take effect.