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IPv6 on Raspberry Pi
May 1, 2014
  • Linux

Introduction

There are two types of IPv6 configuration for IPv4.

  • 6in4: This is most common configuration for IPv4 users. This type of IPv6 will use TSP (Tunnel Setup Protocol).
  • 6to4: Automatic tunnel. If you have a public IPv4 address, this method is out-of-box for linux users. It use a mapping between IPv4 address and IPv6 prefix. (e.q. 2002:XXXX:YYYY::/48 where XXXX:YYYY is IPv4 address in hex). I prefer to use 6to4 tunnel due to native support by linux.

Configuration

There are two steps to make a IPv6-ready home box.

  1. A 6to4 tunnel interface and binding an IPv6 address to it.
  2. Setup radvd (optional if you want to setup an IPv6 subnet)

6to4 Interface

First of all, the sit module must be loaded and then the sit0 interface will be created automatically.

modprobe ipv6
modprobe sit

Now we need an IPv6 address for sit0 interface according to the IPv4 address of WAN interface.

ip -6 addr add 2002:XXXX:YYYY::1/16 dev sit0

The prefix must be 16 due to all 6to4 IPv6 addresses should be handled by sit0.

Then the default route should be:

ip -6 ro add 2000::/3 via ::192.88.99.1 dev sit0 metric 1

Or:

ip -6 ro add 2000::/3 via 2002:c058:6301::1 dev sit0 metric 1

The radvd daemon

If you want to setup an IPv6 subnet, there are two things must be done.

  1. Setup routing entry and enable forwarding function
  2. Enable radvd daemon

Here we assume the interface name, which is used to send RA, is eth0

ip -6 ro add 2002:XXXX:YYYY:1::/64 dev eth0 metric 1
sysctl net.ipv6.conf.all.forwarding = 1

In order to send RA, you have to install radvd and configure /etc/radvd.conf as following

interface eth0
{
   AdvSendAdvert on;
   prefix 0:0:0:1::/64
   {
      Base6to4Interface ppp0;
   };
};

You can replace the ppp0 with your WAN interface name. Then run the radvd daemon.

Reference