Rich Freeman on 4 Mar 2014 09:38:24 -0800

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Re: [PLUG] Using IPv6

On Tue, Mar 4, 2014 at 12:13 PM,  <> wrote:
> => On Tue, Mar 4, 2014 at 11:25 AM,  <> wrote:
> =>>    As far as I know, VZ has not rolled out IPv6 in our area (or any
> =>> area,
> =>> as far as a quick search can tell), and it is unclear what it would
> =>> look like if they did. So the point is moot for now. However, if they
> =>> do it in a sensible way, it shouldn't be much different than if you had
> =>> a tunnel and your own router, so I would suggest starting with that.
> =>> You can use a Linux box for a router, if you'd like, and either SIXXS
> =>> or Hurricane Electric would work as a free tunnel broker.
> =>
> => Can you point me to any configs where you run a tunnel gateway on one
> => box, and then manage DHCP/DNS/etc from another?  Ideally the tunnel
> => should change its IP from time to time.
>    I have a NetBSD box at home acting as the tunnel gateway and an
> off-the-shelf residential router handling IPv4/DHCP/DNS. I have an HE
> tunnel, so I had to configure the VZ router to send IP protocol 41 to
> my tunnel box. (I configured the tunnel box with a static IPv4
> (internal) address so I don't have to worry about its address
> changing.) HE has a URL-based service to handle tunnel reconfiguration
> when the VZ IP changes.

I'm talking about IPv6 DNS - AAAA records, not A records.  Ditto for
DHCP - I don't think you can do PXE without DHCP.

And I'm talking about the IPv6 changing - not the IPv4.

> => I've yet to see anything that combines any of this with PXE booting,
> => or with running DNS with dynamic IPs, or running DHCP (if needed) from
> => a box other than the gateway.  I certainly haven't seen anything where
> => you have multiple gateways on a subnet.
>    I use EUI-64 with my IPv6 subnet prefix and network id to derive IPv6
> addresses based on the MAC address of the box, so I can just do static
> DNS entries. (If VZ doesn't give you a fixed prefix, the whole exercise
> would likely be a waste of time, anyway.)

I doubt VZ would give out fixed prefixes.  Obviously if they do that
will make life easier.  However, I imagine it is subject to change,
and I want to understand how you would run a network if all your IPs
change from time to time.

>  I don't see how PXE would be
> affected by having IPv6 around. DHCPv6 exists, but I have never used it
> or looked into it much.

You need DHCP to run PXE.  If you're running an IPv6 network, that
means that you need your DHCP server to co-exist with it, unless you
run IPv4 just for PXE.  I guess you might have to do that anyway for
devices that don't support PXE over IPv6 (though I wouldn't be
surprised if PXE is an ethernet-level protocol in which case it
doesn't matter, aside from the DHCP server playing nicely).

Bottom line is that if I'm running DHCPv6 it needs to hand out the
correct stateless config addresses, taking into the account the
possibility of a changing prefix, and that prefix would have to be
obtained from the gateway.

> I'm not sure what you mean by multiple
> gateways. If you just mean IPv4 vs. IPv6, the routing is separate, so
> having a gateway for each is not a problem.

I was talking more than one IPv6.  For example, running two separate
tunnel brokers, or having more than one ISP.  That is straightforward
to do with IPv4, though generally it involves NAT.

I doubt I'd need to run this, but if I could find docs on how it works
with IPv6 I could probably figure out what I need in order to make my
single-homed network operate.

>    It depends on what you want it to do, I suppose.

I want to run an IPv6-only internal network.  I don't want to use NAT.
 I want to run PXE boot.  I want to have DNS for all hosts on the
internal network.  I don't want to depend on the gateway to do
anything other than forwarding packets.

I'm just trying to figure out how to do it.  :)

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