IPv6 routing with EdgeRouter and SixXS

Recently I have migrated my home router from OpenBSD to Ubiquiti EdgeRouter. In this post I shall explain how to configure IPv6 tunnel provided by SixXS and how to route an IPv6 subnet into your internal network.

Prerequisites

This tutorial assumes you already have your EdgeRouter configured for IPv4 operation and that you have static, public IPv4 address. It is more complicated to configure the tunnel if you don’t have static IPv4 address on an external interface, since EdgeRouter does not provide support for SixXS dynamic tunnel configuration protocol known as TIC. Operation with a dynamic IPv4 address is still possible, as one of the users created a script to support the heartbeat protocol.

Update 2015-05-24: Florian G. Pflug prepared a package that adds support for AICCU (TIC protocol tool) to Vyatta. I didn’t test it but it looks promising. See here.

Configuring the tunnel interface

Let’s suppose SixXS provided you with a static tunnel:

PoP IPv4200.200.100.100
Your IPv4Static, currently 100.11.12.13
IPv6 Prefix2001:1:2:3::1/64
PoP IPv62001:1:2:3::1
Your IPv62001:1:2:3::2
set interfaces tunnel tun0 address '2001:1:2:3::2/64'
set interfaces tunnel tun0 encapsulation sit
set interfaces tunnel tun0 local-ip 100.11.12.13
set interfaces tunnel tun0 remote-ip 200.200.100.100

In the above example address is your IPv6 end of the tunnel, local-ip is your external IPv4 address, remote-ip is the IPv4 address of PoP assigned to you by SixXS.

Note there’s no need to manually set the IPv6 address of the PoP at this point.

After committing these changes, it should now be possible to ping6 the PoP’s IPv6 address from the router.

Configuring the default route

Just add a static route to ::/0 (IPv6 equivalent of 0.0.0.0) through your PoP’s IPv6 address. The next-hop parameter should always point to IPv6 address of the PoP.

set protocols static route6 '::/0' next-hop '2001:1:2:3::1'

After committing this change, you should be able to successfully ping6 addresses on the internet from the router.

Routing the IPv6 subnet into your internal network

Fist thing to do is to check your subnet configuration at SixXS site. These days SixXS is by assigning a separate /64 network for every tunnel. However, you may still want to request a separate /48 network. Let’s say a network with prefix 2001:5:6::/64 was assigned to you. To be able to use addresses with this prefix, you just need to configure internal ethernet interface (in this example eth2).

set interfaces ethernet eth2 address '2001:5:6::1/64'

Now, machines on the internal network can have addresses assigned from this prefix. They will use the address configured above as their gateway.

Enabling stateless IPv6 addressing for internal network

The easiest way of configuring IPv6 addresses on internal network is stateless autoconfiguration, as described in RFC 4862. Alternatively, you could use DHCPv6, which is also supported by EdgeOS. However, since stateless configuration is so easy to achieve, we’ll do that here.

set interfaces ethernet eth2 ipv6 router-advert prefix '2001:5:6::/64' 
set interfaces ethernet eth2 ipv6 router-advert send-advert true

Don’t forget to commit your changes.

All major modern operating systems support stateless IPv6 configuration out of the box. At least in OS X, NetBSD and recent CentOS/RHEL versions it is enabled by default.

On Linux you can quickly check for public IPv6 addresses with the following command:

$ ip a s | grep inet6 | grep global
    inet6 2001:5:6:(...)/64 scope global dynamic 

Congratulations, machines on your internal network now have public IPv6 addresses. You should be able to ping6 the internet addresses, visit IPv6-enabled web sites from machines on the internal network, and so on.

Firewall considerations

Configuring the firewall is out of scope of this article. However, here are a few helpful tips: