IP version 6 with Dual-stack using a Tunnel broker 6in4 – PFSense/ASA -Part 01

If your ISP doesn’t have Native IP version 6 Support with Dual Stack  here is a workaround to get it setup for your home lab enviroment

What you need

> Router/Firewall/UTM that supports IPv6 Tunneling

  • PFsense/OpenSense/VyOS
  • DD-WRT 
  • Cisco ISR
  • Juniper SRX

> Active Account with an Ipv6 Tunnel Broker

      For this example we are going to be using Hurricane Electric Free IPv6 Tunnel Broker

Overview of the setup

For part 1 of this series  we are going to cover the following

  • Dual Stack Setup
  • DHCPV6 configuration and explanation

– Guide –

I used my a Netgate router running PfSense to terminate the 6in4 tunnel.it adds the firewall and monitoring capabilities on your Ipv6 network

Before we begin, we need to make a few adjustments on the firewall

Allow IPv6 Traffic

On new installations of pfSense after 2.1, IPv6 traffic is allowed by default. If the configuration on the firewall has been upgraded from older versions, then IPv6 would still be blocked. To enable IPv6 traffic on PFsense, perform the following:

  • Navigate to System > Advanced on the Networking tab
  • Check Allow IPv6 if not already checked
  • Click Save

Allow ICMP

ICMP echo requests must be allowed on the WAN address that is terminating the tunnel to ensure that it is online and reachable.

Firewall> Rules > WAN
Create a regular tunnel.

Enter your IPv4 address as the tunnel’s endpoint address.

Note – After entering your IPv4 address, the website will check to make sure that it can ping your machine. If it cannot ping your machine, you will get an error like the one below:

You can access the tunnel information from the accounts page

While you are here go to “Advance Tab” and setup an “Update key”. (We need it later)

Create and Assign the GIF Interface

Next, create the interface for the GIF tunnel in pfSense. Complete the fields with the corresponding information from the tunnel broker configuration summary.

  • Navigate to Interfaces > (assign) on the GIF tab.
  • Click fa-plus Add to add a new entry.
  • Set the Parent Interface to the WAN where the tunnel terminates. This would be the WAN which has the Client IPv4 Address on the tunnel broker.
  • Set the GIF Remote Address in pfSense to the Server IPv4 Address on the summary.
  • Set the GIF Tunnel Local Address in pfSense to the Client IPv6 Address on the summary.
  • Set the GIF Tunnel Remote Address in pfSense to the Server IPv6 Address on the summary, along the with prefix length (typically / 64).
  • Leave remaining options blank or unchecked.
  • Enter a Description.
  • Click Save.

Example GIF Tunnel.

Assign GIF Interface

Click fa-plus on Interfaces > (Assignments)

choose the GIF interface to be used for an OPT interface. In this example, the OPT interface has been renamed WAN_HP_NET_IPv6. Click Save and Apply Changes if they appear.


Configure OPT Interface

With the OPT interface assigned, Click on the OPT interface from the Interfaces menu to enable it  Keep IPv6 Configuration Type set to None.

Setup the IPv6 Gateway

When the interface is configured as listed above, a dynamic IPv6 gateway is added automatically, but it is not yet marked as default.

  • Navigate to System > Routing
  • Edit the dynamic IPv6 gateway with the same name as the IPv6 WAN created above.
  • Check Default Gateway.
  • Click Save.
  • Click Apply Changes.
Status > Gateways to view the gateway status. The gateway will show as “Online” if the configuration is successful

Set Up the LAN Interface for IPv6

The LAN interface may be configured for static IPv6 network. The network used for IPv6 addressing on the LAN Interface is an address in the Routed /64 or /48 subnet assigned by the tunnel broker.

  • The Routed /64 or /48 is the basis for the IPv6 Address field

For this exercise we are going to use ::1 for the LAN interface IP from the Prefixes provided above

Routed /64 : 2001:470:1f07:79a::/64

Interface IP – 2001:470:1f07:79a::1

Set Up DHCPv6 and RA (Router Advertisements)

Now that we have the tunnel up and running we need to make sure devices behind the lan interface can get a IPv6 address

There are couple of ways to handle the addressing

Sateless Auto Address Configuration (SLAAC)

SLAAC just means Stateless Auto Address Configuration, but it shouldn’t be confused with Stateless DHCPv6. In fact, we are talking about two different approaches.

SLAAC is the simplest way to give an IPv6 address to a client, because it exclusively rely on Neighbor Discovery Protocol. This protocol, that we simply call NDP, allows devices on a network to discover their Layer 3 neighbors. We use it to retrieve the layer 2 reachability information, like ARP, and to find out routers on the network.

When a device comes online, it sends a Router Solicitation message. It’s basically asking “Are there some routers out there?”. If we have a router on the same network, that router will reply with a Router Advertisement (RA) message. Using this message, the router will tell the client some information about the network:

  • Who is the default gateway (the link-local address of the router itself)
  • What is the global unicast prefix (for example, 2001:DB8:ACAD:10::/64)

With these information, the client is going to create a new global unicast address using the EUI-64 technique. Now the client has an IP address from the global unicast prefix range of the router, and that address is valid over the Internet.

This method is extremely simple, and requires virtually no configuration. However, we can’t centralize it and we cannot specify further information, such as DNS settings. To do that, we need to use a DHCPv6 technique

Just like IP v4 we need to setup DHCP for the IPv6 range for the devices behind the firewall to use SLAAT

Stateless DHCPv6

Stateless DHCPv6 brings to the picture the DHCPv6 protocol. With this approach, we still use SLAAC to obtain reachability information, and we use DHCPv6 for extra items.

The client always starts with a Router Solicitation, and the router on the segment responds with a Router Advertisement. This time, the Router Advertisement has a flag called other-config set to 1. Once the client receives the message, it will still use SLAAC to craft its own IPv6 address. However, the flag tells the client to do something more.

After the SLAAC process succeed, the client will craft a DHCPv6 request and send it through the network. A DHCPv6 server will eventually reply with all the extra information we needed, such as DNS server or domain name.

This approach is called stateless since the DHCPv6 server does not manage any lease for the clients. Instead, it just gives extra information as needed.

Configuring IPv6 Router Advertisements

Router Advertisements (RA) tell an IPv6 network not only which routers are available to reach other networks, but also tell clients how to obtain an IPv6 address. These options are configured per-interface and work similar to and/or in conjunction with DHCPv6.

DHCPv6 is not able to send clients a router for use as a gateway as is traditionally done with IPv4 DHCP. The task of announcing gateways falls to RA.

Operating Mode: Controls how clients behave. All modes advertise this firewall as a router for IPv6. The following modes are available:

  • Router Only: Clients will need to set addresses statically
  • Unmanaged: Client addresses obtained only via Stateless Address Autoconfiguration (SLAAC).
  • Managed: Client addresses assigned only via DHCPv6.
  • Assisted: Client addresses assigned by either DHCPv6 or SLAAC (or both).

Enable DHCPv6 Server on the interface

Setup IPv6 DNS Addresses

we are going to use cloud-flare DNS (At the time of writing CF is rated as the fastest resolver by Thousandeyes.com)


  • 2606:4700:4700::1111
  • 2606:4700:4700::1001

Keeping your Tunnel endpoint Address Updated with your Dynamic IP

This only applies if you have a dynamic IPv4 from your ISP

As you may remember from our first step when registering the 6in4 tunnel on the website we had to enter our Public IP and enable ICMP

We need to make sure we keep this updated when our IP changes ovetime

There are few ways to accomplish this

  • Use PFsense DynDNS feature 

dnsomatic.com  is wonderful free service to update your dynamic IP on multiple locations, i used this because if needed i have the freedom to change routers/firewalls with out messing up my config (Im using a one of my RasPi’s to update DNS-O-Matic)

im working on another article for this, will link it to this section ASAP


Few Notes –

Android OS, Chrome OS still doesn’t support DHCPv6

Mac OSX and windows 10, Server 2016 uses and prefers Ipv6

Check the windows firewall rules if you have issues with NAT rules and manually update rules

Your MTU will drop-down since you are sending the IPv6 headers encapsulated in the Ipv4 packets.Personally i have no issues with my Ipv6 network Behind a spectrum DOCSIS modem. but this may cause issues depending on your ISP ie : CGNat

Here is a good write up https://jamesdobson.name/post/mtu/


Part 2

With Part two of this series we will use an ASA for IPv6 using the PFsense router as an tunnel-endpoint

Example Network

Link spotlight

– Understanding IPv6 EUI-64 Bit Address

– IPv6 Stateless Auto Configuration

– Configure the ASA to Pass IPv6 Traffic

– Setup IPv6 TunnelBroker – NetGate

– ipv6-at-home Part 1 | Part II | Part III

Until next time….