Setting up an IPv6 tunnel (was: Re: static IP & DHCP problems on LAN)

[Colin Law]

On 13 March 2013 00:43, Karl Auer <kauer at biplane.com.au> wrote:
> On Tue, 2013-03-12 at 16:24 +0000, Colin Law wrote:
>> On 12 March 2013 16:08, Karl Auer <kauer at biplane.com.au> wrote:
>> > That is how the tunneling works with singleton tunnels. If you get a
>> > prefixed tunnel, then you can run a router advertiser in your network
>> > advertising the prefix (or some part of it) and your whole network will
>> > autoconfigure itself with IPv6 addresses. It is seriously cool the first
>> > time this happens.
>>
>> Would I not need an ipv6 aware router to do this?
>
> Yes and no. What you are doing is turning a Linux box into a router. You
> install and run a program called radvd on the same host as the tunnel,
> configuring it with the prefixes you want to advertise. Hosts
> autoconfigure themselves based on those prefixes, and route (first hop)
> through the radvd host to the IPv6 Internet across the tunnel.
>
> Your CPE (your router/modem, such as your Netgear) is not involved in
> IPv6 at all. It's forwarding IPv4 packets that *contain* IPv6 packets,
> but it doesn't know anything about that content.
>
> radvd is not needed for a singleton tunnel, so you can start by getting
> just one host onto the IPv6 Internet, then move on to experiment with
> prefixes. Or you can experiment with radvd *without* a tunnel, and just
> get IPv6 happening on your network, without IPv6 Internet access. Works
> a treat.
>
>> Probably neither am I.  In the previous thread the suggestion was that
>> by using ipv6 tunnelling one could avoid the requirement for fixed ip
>> addresses on the LAN.  However in order to communicate between
>> machines on the LAN it still seems that fixed ipv4 addresses makes
>> life easier.  I was enquiring if ipv6 would somehow provide an
>> alternative.
>
> No, not really. Using a tunnel (or at least a TSP-style tunnel) means
> that you don't need a static address on the outside interface of your
> CPE, and once the tunnel is up, you end up with static IPv6 addresses on
> your hosts, making them directly addressable from the Internet. That
> makes it much easier to communicate from the outside Internet into your
> network - no more port forwarding etc.
>
>> To use ipv6 /between/ machines on the LAN however, would I need an
>> ipv6 aware router?
>
> See above - you don't need your CPE to be IPv6 aware, you can just have
> a tunnel set up to get a prefix, and radvd to advertise that prefix, and
> then all your hosts will start doing IPv6 by themselves. If you want to
> use *names* to refer to them, then you need to put DNS into the mix. If
> you want to automate the DNS, you need to add DHCP into the mix (or set
> up the hosts to do DDNS themselves). The last two steps are essentially
> identical for v4 and v6.
>
> If your CPE *can* do the tunnel thing and the router advertising thing
> itself, then so much the better (my little Mikrotik RB951-2n does it
> like a champ), but it is not hard to put the tunnel endpoint on just
> about any host in your network.

OK, thanks for the info.  Will have a play.

Cheers

Colin