VirtualBox images to experiment with IPv6

Around me I noticed that a lot of people don’t have hands-on experience with IPv6. The networks they work in do not support IPv6 nor does their ISP provide them with native IPv6 connectivity at home.

On my local systems I often use Virtual Box to set up (IPv6) testing environments. I thought I’d create some Virtual Machine images to get some hands-on experience with IPv6.

The images and README can be found on Github and are aimed to be easy to install and work with.


To run the images you need to have Virtual Box installed. You also should be able to use the Linux command line as the Virtual Machines are based on Ubuntu 16.04.

More information can be found in the repository on Github in the README file.


You can download the images here.

How to use

Please take a look at the README on Github. It tells you how to use them.

Happy testing!

ISC Kea DHCPv6 server


In most situations StateLess Address AutoConfiguration (SLAAC) works just fine when you work with simple clients in a IPv6 network. But in other cases you want to assign pre-defined addresses or prefixes to clients and there DHCPv6 comes in to play.

While working on the IPv6 implementation for Apache CloudStack I found Kea, a DHCPv6 server from ISC.


With IPv4 you could easily identify a client based on the MAC-address it send the DHCP request from. With IPv6 there is a DUID. The “DHCP Unique Identifier”. This is generated by the client and then used by the DHCPv6 server. A few possibilities the clients can choose from:

  • DUID-LL: DUID Based on Link-layer Address
  • DUID-LLT: Link-layer Address Plus Time
  • DUID-EN: Assigned by Vendor Based on Enterprise Number

While DUID seems nice, it can’t be dictated by the DHCPv6 server. The client generates the DUID itself and sends it towards the server. Not something you prefer if your are not in control of the clients.

In a cloud you are in control over the MAC-address, so that is what you want to use where possible. It can’t be spoofed by the client.


Kea is a DHCPv4/DHCPv6 server being developed by the Internet Systems Consortium. It is a extensible and flexible DHCP server. Facebook uses it in their datacenters.

My goal was very simple. Set up Kea and see if I can use it to hand out an address to a client.


I download the tarball and tested it with this configuration between two simple KVM VMs on my desktop.

    "Dhcp6": {
        "renew-timer": 1000,
        "rebind-timer": 2000,
        "preferred-lifetime": 3000,
        "valid-lifetime": 4000,
        "lease-database": {
            "type": "memfile",
            "persist": true,
            "name": "/tmp/kea-leases6.csv",
            "lfc-interval": 1800
        "interfaces-config": {
            "interfaces": [ "eth1/2001:db8::1" ]
        "mac-sources": ["duid"],
        "subnet6": [
                "subnet": "2001:db8::/64",
                "id": 1024,
                "interface": "eth1",
                "pools": [
                    { "pool": "2001:db8::100-2001:db8::ffff" }
                "pd-pools": [
                        "prefix": "2001:db8:fff::",
                        "prefix-len": 48,
                        "delegated-len": 60
                "reservations": [
                        "hw-address": "52:54:00:d6:c2:a9",
                        "ip-addresses": [ "2001:db8::5054:ff:fed6:c2a9" ]

Starting Kea with this configuration was rather simple:

Starting Kea

$ kea-dhcp6 -c /etc/kea.json -d


When it starts you see some interesting bits in the log:

DHCP6_CONFIG_NEW_SUBNET a new subnet has been added to configuration: 2001:db8::/64 with params t1=1000, t2=2000, preferred-lifetime=3000, valid-lifetime=4000, rapid-commit is disabled
DHCPSRV_CFGMGR_ADD_SUBNET6 adding subnet 2001:db8::/64
HOSTS_CFG_ADD_HOST add the host for reservations: hwaddr=52:54:00:d6:c2:a9 ipv6_subnet_id=1024 hostname=(empty) ipv4_reservation=(no) ipv6_reservation0=2001:db8::5054:ff:fed6:c2a9
HOSTS_CFG_GET_ONE_SUBNET_ID_HWADDR_DUID get one host with IPv6 reservation for subnet id 1024, HWADDR hwtype=1 52:54:00:d6:c2:a9, DUID (no-duid)
HOSTS_CFG_GET_ALL_HWADDR_DUID get all hosts with reservations for HWADDR hwtype=1 52:54:00:d6:c2:a9 and DUID (no-duid)
HOSTS_CFG_GET_ALL_IDENTIFIER get all hosts with reservations using identifier: hwaddr=52:54:00:d6:c2:a9
HOSTS_CFG_GET_ALL_IDENTIFIER_COUNT using identifier hwaddr=52:54:00:d6:c2:a9, found 0 host(s)
HOSTS_CFG_GET_ONE_SUBNET_ID_HWADDR_DUID_NULL host not found using subnet id 1024, HW address hwtype=1 52:54:00:d6:c2:a9 and DUID (no-duid)
HOSTS_CFG_GET_ONE_SUBNET_ID_ADDRESS6 get one host with reservation for subnet id 1024 and including IPv6 address 2001:db8::5054:ff:fed6:c2a9
HOSTS_CFG_GET_ALL_SUBNET_ID_ADDRESS6 get all hosts with reservations for subnet id 1024 and IPv6 address 2001:db8::5054:ff:fed6:c2a9
HOSTS_CFG_GET_ALL_SUBNET_ID_ADDRESS6_COUNT using subnet id 1024 and address 2001:db8::5054:ff:fed6:c2a9, found 0 host(s)
HOSTS_CFG_GET_ONE_SUBNET_ID_ADDRESS6_NULL host not found using subnet id 1024 and address 2001:db8::5054:ff:fed6:c2a9
DHCPSRV_MEMFILE_DB opening memory file lease database: lfc-interval=1800 name=/tmp/kea-leases6.csv persist=true type=memfile universe=6
DHCPSRV_MEMFILE_LEASE_FILE_LOAD loading leases from file /tmp/kea-leases6.csv

You can see it has one reservation based on the MAC-address of the client which it handed out after it booted:

ALLOC_ENGINE_V6_HR_ADDR_GRANTED reserved address 2001:db8::5054:ff:fed6:c2a9 was assigned to client duid=[00:01:00:01:1e:47:7e:66:52:54:00:d6:c2:a9], tid=0xe7899a

Ubuntu client

The client was a simple Ubuntu 14.04 client with this network configuration:

auto eth0
iface eth0 inet dhcp
iface eth0 inet6 dhcp

And indeed, it obtained the correct address:

root@ubuntu1404:~# ip addr show dev eth0
2: eth0:  mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 52:54:00:d6:c2:a9 brd ff:ff:ff:ff:ff:ff
    inet brd scope global eth0
       valid_lft forever preferred_lft forever
    inet6 2001:db8::5054:ff:fed6:c2a9/64 scope global deprecated dynamic 
       valid_lft 62sec preferred_lft 0sec
    inet6 fe80::5054:ff:fed6:c2a9/64 scope link 
       valid_lft forever preferred_lft forever

Lease database

Kea can store the leases in a CSV file or MySQL database if you want. In this test I used /tmp/kea-leases6.csv as a CSV file to store the leases in.

In production a MySQL database is probably easier to use, but for the test CSV worked just fine.

Using the internet on a IPv6-only network

At home I have native IPv6 via my ISP ZeelandNet since June 2014. Ever since I’ve been using the internet via IPv6 where possible.

Yesterday I thought it was time to create a IPv6-only VLAN + SSID at home and see what parts of the internet I could use while being on a IPv6-only network. No NAT64 or anything, just IPv6.

Linux router

I’m using a Soekris NET6501 with Ubuntu as my router at home. So I created a new VLAN and used that VLAN tag to create a new SSID on my Access Point.

Under Ubuntu I configured:

  • Radvd for Router Advertisements
  • Wide DHCPv6 Server for DNS servers

IPv6-only under iOS 9.1

I have an iPhone 5s and iPad Air 2 both running iOS 9.1 and I thought it was best to use these for testing the IPv6-only network.

They connected just fine! But the WiFi overview didn’t show any IP-Address. Seems that is still IPv4-only.

iOS 9.1 IPv6-only network

And showed that I had IPv6 connectivity only.

IPv6 test iOS 9.1

What works?

You might think that the internet breaks, but I think that already a lot of the large services work. A list of things which work:

  • Facebook / Messenger
  • Google: Search, YouTube, Maps and Gmail
  • NOS (Dutch news
  • Netflix
  • Apple Notifications
  • My own website and E-Mail
  • Various local sites I visit

What does not work?

Well, this could be a very long list. But there are certain services which should be highlighted for not supporting IPv6:

  • Twitter
  • Github
  • Apple App Store
  • Spotify
  • All Dutch Online banking

So yes, the biggest part of the internet does not work over IPv6. But most of the things work for me.

I’ll keep testing the internet using this IPv6-only SSID and I’ll probably keep bugging various admins to turn on IPv6.

Ubuntu and the changing MAC address with bonding

With the ‘new’ style for configuring bonding under Ubuntu your bond device will not always have the same MAC address across reboots.

For example, you configure your bond in the /etc/network/interfaces file:

auto p9p1
iface p9p1 inet manual
        bond-master bond0

auto p10p1
iface p10p1 inet manual
        bond-master bond0

auto bond0
iface bond0 inet manual
        bond-slaves none
        bond-mode 4
        bond-miimon 100
        bond-updelay 5
        bond-downdelay 5

During boot, both interface p9p1 and p10p1 will be hot-plugged under bond0. The first device to be plugged into the bonding device determines which MAC address the bonded device gets.

Due to hardware timing it might be p9p1 OR p10p1 which is the first. This behavior makes the MAC address selection inconsistent between reboots and that might cause problems with:

  • DHCP for IPv4
  • IPv6 with SLAAC (Stateless Auto Configuration)
  • DHCPv6

This has been filed as bug #1288196 with Ubuntu, but no fix from that side so far.

The solutions for now:

auto p9p1
iface p9p1 inet manual
        bond-master bond0

auto p10p1
iface p10p1 inet manual
        pre-up sleep 5
        bond-master bond0

This makes sure p10p1 always comes online 5 seconds after p9p1.

But you can also set a static MAC address for the bonding device:

auto bond0
iface bond0 inet manual
        hwaddress fe:80:12:04:6d:6f
        bond-slaves none
        bond-mode 4
        bond-miimon 100
        bond-updelay 5
        bond-downdelay 5

Choose what you prefer or works best in your situation.