IPv6-Lab/README.md

IPv6-Lab

Initial situation

In this project, a laboratory for IPv6 will be set up using a desktop computer with a current Debian system. To use the computer furthermore for its actual purpose, this should be done as far as possible without stirring up a lot of dust (e.g. using various outdated network backends).

OS: Debian GNU/Linux Trixie (testing)
Kernel: 6.17.13-1 amd64
Network backend: NetworkManager
Hypervisor: KVM
Virtual switch: Open vSwitch 3.6.0

Required packages

• openvswitch-switch
• gvncviewer
• qemu-system
• libvirt-daemon-system
• libvirt-daemon-system
• virt-manager

Network topology

Configuring Systems

Bridge br0

The bridge is part of the host system. Thus, it is configured using the network manager command line tool. These settings will be permanent.

Caution

I was not able to get this working with wifi interfaces. The reason is probably, that the access point is not accepting packets from other MAC adresses than the wifi interface. There is a way using ebtables to mask all MAC adresses, but this seems pretty buggy to me. Consider using ULA in an offline lab if you don't have ethernet interfaces on your Laptop.

Info about current connetions

# nmcli con show

Add bridge

# nmcli con add ifname br0 type bridge con-name br0

Add interface to the bridge

# nmcli con add type bridge-slave ifname <interface_name> master br0

Turn on the bridge (and turn off bridge-slave)

# nmcli con down "Wired connection 1"
# nmcli con up br0

Wait a few seconds

$ nmcli con show

Hypervisor

KVM is used as a hypervisor in this project. You may use virsh on the cli or virt-manager as a graphical tool.

Create virtual networks on hypervisor

Here we create two networks on the hypervisor. The first is used by the edge router impala to connect to the host network, the second is needed by the hosts in the lab network. Create a file named bridged-network.xml with the following content

<network>
    <name>bridged-network</name>
    <forward mode="bridge" />
    <bridge name="br0" />
</network>

Then we need the network for the virtual switch served by openvswitch. Create a file named ovs-network.xml with this content

<network>
  <name>vSwitch0</name>
  <forward mode="bridge"/>
  <bridge name="labbr1"/>
  <virtualport type='openvswitch'/>
</network>

In case you use virsh, you need to run the following commands to create the network on the hypervisor:

$ virsh net-define bridged-network.xml
$ virsh net-define ovs-network.xml

Then start it

$ virsh net-start bridged-network
$ virsh net-start vSwitch0
$ virsh net-autostart bridged-network
$ virsh net-autostart vSwitch0
$ virsh net-list
 Name              Status   Automatischer Start   Bleibend
------------------------------------------------------------
 bridged-network   Aktiv    ja                    ja
 vSwitch0          Aktiv    ja                    ja

impala

impala is the WAN router of the lab. On the external interface, the router acts as a DHCPv6 client in order to receive a Prefix Delegation from the DSL-Router (Fritz!Box in this case). On the internal interface impala will serve Router Advertisements which is necessary for SLAAC. The hosts in the lab environment connectetd to the vSwitch will receive a prefix via SLAAC this way. Thus, we need two network interfaces on this virtual host system:

The external interface ist connexted to the bridge on the host system.

<interface type="network">
  <mac address="52:54:00:62:85:19"/>
  <source network="bridged-network"/>
  <model type="virtio"/>
  <address type="pci" domain="0x0000" bus="0x01" slot="0x00" function="0x0"/>
</interface>

The internal interface has to be connected to the vSwitch0.

<interface type="bridge">
  <source network="vSwitch0" portid="672dad49-ab32-4369-81d3-4a1e7e69b0de" bridge="labbr1"/>
  <virtualport type="openvswitch"/>
  <model type="virtio"/>
</interface>

DHCP Client

The dhcpcd package has to be installed on the OpenBSD system.

# pkg_add dhcpcd
# rcctl enable dhcpcd

Edit the config file /etc/dhcpcd.conf

ipv6only
noipv6rs

script ""

allowinterfaces vio0 vio1
interface vio0
  ipv6rs
  ia_pd 1 vio1/1 

gto

gto has one interface on vSwitch0

<interface type="bridge">
  <mac address="52:54:00:26:9b:f0"/>
  <source bridge="labbr1"/>
  <virtualport type="openvswitch">
    <parameters interfaceid="d9935aa6-952e-4f7b-8d55-9e8c2d2bc6a5"/>
  </virtualport>
  <model type="virtio"/>
  <address type="pci" domain="0x0000" bus="0x01" slot="0x00" function="0x0"/>
</interface>