Configuring IPv6 on virtual machines with ESXi

This tutorial explains how to configure IPv6 on virtual machines on ESXi hypervisors.

Before you start

To complete the actions presented below, you must have:

• A Scaleway account logged into the console
• Owner status or IAM permissions allowing you to perform actions in the intended Organization
• An SSH key
• A Dedibox running ESXi 6.5 or later
• Enabled SLAAC for your Dedibox
• Requested an IPv6 prefix
• Installed a virtual machine running Ubuntu 20.04 or later and configured a failover IPv4 on it

1. Log into your virtual machine using SSH.

2. Run the command ip a to display your current network configuration. The command returns an output as follows:

   1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
   link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
   inet 127.0.0.1/8 scope host lo
      valid_lft forever preferred_lft forever
   inet6 ::1/128 scope host
      valid_lft forever preferred_lft forever
   2: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
   link/ether 00:50:56:01:fa:b9 brd ff:ff:ff:ff:ff:ff
   altname enp3s0
   inet your.fail.over.ip/32 scope global ens160
      valid_lft forever preferred_lft forever
   inet6 fe80::250:56ff:fe01:fab9/64 scope link
      valid_lft forever preferred_lft forever

   Take note of the following information from the output above:

   • The name of the network interface (here ens160)
   • The local IPv6 of your VM (here fe80::250:56ff:fe01:fab9/64)

3. Open the file /etc/dhcp/dhclient6.conf in a text editor and edit it as shown below. Then save the file and quit the text editor.

   interface "ens160" {
       send dhcp6.client-id DUID;
   }

   Important

   Edit the name of the internet interface to one of your VMs and replace DUID with the DUID of your prefix.

4. Open the file /etc/systemd/system/dhclient.service in a text editor and edit it as shown below. Then save and exit the editor.

   [Unit]
   Description=dhclient for sending DUID IPv6
   After=network-online.target
   Wants=network-online.target
   
   [Service]
   Restart=always
   RestartSec=10
   Type=forking
   ExecStart=/sbin/dhclient -cf /etc/dhcp/dhclient6.conf -6 -P -v eno1
   ExecStop=/sbin/dhclient -x -pf /var/run/dhclient6.pid
   
   [Install]
   WantedBy=network.target

5. Enable the service to start automatically after each reboot of the machine. Then start the service manually for the first time.

   systemctl enable dhclient.service
   systemctl start dhclient.service

6. Verify that the service is running with the following command:

   systemctl status dhclient.service

   The command above returns an output as follows:

   ● dhclient.service - dhclient for sending DUID IPv6
       Loaded: loaded (/etc/systemd/system/dhclient.service; enabled; vendor pres>
       Active: active (running) since Thu 2022-02-24 12:18:03 UTC; 27min ago
     Main PID: 5342 (dhclient)
       Tasks: 4 (limit: 4627)
       Memory: 1.6M
       CPU: 23ms
       CGroup: /system.slice/dhclient.service
               └─5342 /sbin/dhclient -cf /etc/dhcp/dhclient6.conf -6 -P -v ens160

7. Edit your Netplan configuration file (probably located at /etc/netplan/01-netcfg.yaml) and edit it as follows:

   network:
   version: 2
   renderer: networkd
   ethernets:
     ens18:
       dhcp4: false
       dhcp6: false
       addresses:
       - FAILOVER_IP/32
       - IP_FROM_YOUR_PREFIX/SUBNET
       gateway4: 62.210.0.1
       gateway6: LOCAL_IPv6
       nameservers:
           addresses: [ "51.159.47.28", "51.159.47.26" ] # Replace the IP of the DNS cache server with the one located in the same physical location as your machine for optimal performances (https://www.scaleway.com/en/docs/account/reference-content/scaleway-network-information/#dns-cache-servers)
   
       routes:
         - to: 0.0.0.0/0
           via: 62.210.0.1
           on-link: true
         - to: "::/0"
           via: "LOCAL_IPv6"
           on-link: true
       nameservers:
           addresses: [ "51.159.47.28", "51.159.47.26" ] # Replace the IP of the DNS cache server with the one located in the same physical location as your machine for optimal performances (https://www.scaleway.com/en/docs/account/reference-content/scaleway-network-information/#dns-cache-servers/)
       accept-ra: no  # Disable Router Advertisements to ignore SLAAC

8. Apply the new network configuration with the following command:

   netplan apply

   You now have configured the IP address, but the IPv6 connectivity is not working yet.

9. Find the gateway for your prefix by running the following command:

   ip -6 route

   The command returns an output as follows:

   ::1 dev lo proto kernel metric 256 pref medium
   YOUR_IPv6_PREFIX/SUBNETMASK dev ens160 proto kernel metric 256 pref medium
   fe80::/64 dev ens160 proto kernel metric 256 pref medium
   default via fe80::7a0c:f0ff:fedf:254d dev ens160 proto static metric 1024 onlink pref medium

   Take note of the default gateway (here fe80::7a0c:f0ff:fedf:254d).

10. Edit your Netplan configuration file again and modify it as follows:

    gateway6: DEFAULT_GATEWAY
    - to: "::/0"
        via: "DEFAULT_GATEWAY"
        on-link: true

    Note

    Remember to replace DEFAULT_GATEWAY with the default gateway found in the previous step.

11. Reload your network configuration for the last time:

    netplan apply

You have now IPv6 connectivity for your virtual machine. You can test it by running a ping6: ping ipv6.google.com.