# Setting up IPv6 private network using radvd (router advertisement daemon)

## Setup

:::info
It is assumed libvirt and vagrant are installed on the system with vagrant-libvirt plugins installed.
:::

Using vagrant set up 2 VMs with an additional eth1 interface on which the IPv6 could be configured.

Steps
1. Copy the below Vagrantfile and install.sh ([Refer Appendix](#Appendix)) into a folder.
2. Run the following command with this folder to bring up both the VMs (server0 and server1)

vagrant up

3 The above step should bring up 2 VMs (server0 and server1 ). This could be tested using the following command

vagrant ssh server0

If this logs into server0 under vagrant user as below, the setup is ready for use.

root@airship105:/home/ekuamaj/workspace/vagrant/radvdtest# vagrant ssh server0
==> server0: The machine you're attempting to SSH into is configured to use
==> server0: password-based authentication. Vagrant can't script entering the
==> server0: password for you. If you're prompted for a password, please enter
==> server0: the same password you have configured in the Vagrantfile.
Last login: Thu Oct 14 05:09:33 2021 from 192.168.121.1
vagrant@router:~$

Repeat the same test for server1.

# Start radvd daemon service

On server0 (the router VM), start the radvd service using the following command.

sudo systemctl restart radvd.service

If the radvd service is up and running, the eth1 of the server1 should now have a global link IPv6 address as below.

root@router:~# ip -6 a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 state UNKNOWN qlen 1000
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 1000
    inet6 fe80::5054:ff:fe97:eb48/64 scope link
       valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 1000
    inet6 2001:468:181:f100:5054:ff:fe3f:d8fc/64 scope global dynamic mngtmpaddr noprefixroute
       valid_lft 86391sec preferred_lft 14391sec
    inet6 fe80::5054:ff:fe3f:d8fc/64 scope link
       valid_lft forever preferred_lft forever

## Check server1 VM for an autoconfigured IPv6 address

The radvd daemon ensures that server1 connected in the same network, is assigned a valid IPv6 address on eth1 as below.

vagrant@controlnode:~$ ip -6 a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 state UNKNOWN qlen 1000
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 1000
    inet6 fe80::5054:ff:feb5:3ad3/64 scope link
       valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 1000
    inet6 2001:468:181:f100:5054:ff:fe2a:1041/64 scope global dynamic mngtmpaddr noprefixroute
       valid_lft 86398sec preferred_lft 14398sec
    inet6 fe80::5054:ff:fe2a:1041/64 scope link
       valid_lft forever preferred_lft forever

# Appendix
## Files
* Vagrantfile

Vagrant.configure("2") do |config|

config.ssh.insert_key = false
config.vm.box = "generic/ubuntu2010"
config.ssh.insert_key = false
config.ssh.private_key_path = ["~/.ssh/id_rsa", "~/.vagrant.d/insecure_private_key"]
config.vm.provision "file", source: "~/.ssh/id_rsa.pub", destination: "~/.ssh/authorized_keys"
config.ssh.username = "vagrant"
config.ssh.password = "vagrant"
config.vm.provision "shell", path: "install.sh"
config.vm.provider :libvirt do |libvirt|
    libvirt.cpus = 4
    libvirt.memory = 8024
    libvirt.machine_virtual_size = 100
end
MACHINE = ["router.dev","controlnode.dev"]
N = 1

(0..N).each do |i|
config.vm.define "server#{i}" do |node|
  node.vm.hostname = MACHINE[i]
  node.vm.network :private_network, ip: "192.168.4.#{10+i}"
end
end
end

* install.sh

#!/bin/bash


# Update Packages
apt-get update
apt-get install radvd radvdump
sed 's/#net.ipv6.conf.all.forwarding=1/net.ipv6.conf.all.forwarding=1/g' /etc/sysctl.conf | sudo tee /etc/sysctl.conf
sed 's/net.ipv6.conf.all.disable_ipv6 = 1/net.ipv6.conf.all.disable_ipv6 = 0/g' /etc/sysctl.conf | sudo tee /etc/sysctl.conf
echo "net.ipv6.conf.default.forwarding=1" | sudo tee -a /etc/sysctl.conf
sysctl -p
cat <<EOF > /etc/radvd.conf
interface eth1
{

    AdvSendAdvert on;
    MinRtrAdvInterval 5;
    MaxRtrAdvInterval 15;

    prefix 2001:468:181:f100::/64
    {
        AdvOnLink on;
        AdvAutonomous on;
    };
};
EOF