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So my /etc/network/interfaces looks like

auto eth0
iface eth0 inet static

# VPN Subnet
auto eth0:1
iface eth0:1 inet static

# ipv6 tunnel
auto tunnel
iface tunnel inet6 v4tunnel
    address 2001:db8:1:1::2
    netmask 64
    ttl 64
    mtu 1280
    gateway 2001:db8:1:1::1

using openswan and xl2tpd I have a working L2TP/IPSec vpn that successfully assigns from the 10.0.1.x range and clients have full ipv4 connectivity. (Used this as a guide)

The part I cannot figure out is how to do the same with with ipv6. I have a /64 with ::1 being the remote endpoint and ::2 being the local machine. ipv6 works fine on the local machine (I can ping I installed radvd, but all the tutorials I can find use it to hand out addresses on a single interface. I'm not too clear on how "router advertisement" works. I figured out that I need profiles for each pppX connection, like so:

interface ppp0 {
    AdvSendAdvert on;
    IgnoreIfMissing on;
    prefix 2001:db8:1:2::/64 {
interface ppp1

where 2001:db8:1:2::/64 is the routed /64 subnet (different from the tunnel subnet) I set it up so that each time a ppp client connected it would get a link local address and then reload radvd so it would broadcast on the new interface. This successfully assigned an ipv6 address from my 2001:db8:1:2::1/64, but there would not be any ipv6 connectivity. I'm not really familiar with any of this, but does anyone know if I'm attacking this from the right direction? Or do I need to do something with bridging or adding routes. This looked similar, but their setup was more complex than mine and just confused me.

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Why are you trying to do router advertisements over PPP? This doesn't make any sense. – Michael Hampton Feb 6 '14 at 18:50
I found a similar solution at… and I've managed to use parts of that solution to make it work for one host, but as I only have a /64 and not a /48 I'm still trying to figure out how to do that for more than one ppp – mcu17818 Feb 6 '14 at 19:23

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