[plug] IPv6 revisited
Adrian at Diskworld.com.au
Wed Jan 15 12:31:32 UTC 2014
The /64 is used to allocate the IP for the end-point of your PPP
session; ie one IP from this subnet will be used for your router's ppp0
and another will be used for the BBA/BRAS interface. This is the
analogous to the dynamic IPv4 address allocated to your router. This IP
will change every time you reconnect.
The /56 is a static subnet which is permanently allocated to your
account. You can either allocate the entire /56 to your LAN
(4,722,366,482,869,645,213,696 IPs!) or break that subnet up into one or
more /64s (a mere 18,446,744,073,709,551,616 IPs). This is the analogous
to the private IP space in IPv4 (ie 192.168.1.0/24). This subnet will
remain static across reconnections. It is from this range that you
should allocate IPs to your LAN machines, either via radvd (Neighbour
Discovery Protocol) or DHCPv6.
I would recommend using a single /64 for your LAN - this leaves you
options to later on allocate other /64s for networks connected to your
LAN. For example, I use a second /64 for my laptop, which is routed via
an IPsec tunnel, giving me IPv6 when I'm away from home. You could even
do more interesting (paranoid?) things, such as using on /64 for your
services and another more tightly firewalled /64 for your client machines.
On 13/01/14 16:39, Andrew Cooks wrote:
> Hi Plug
> I recently implemented IPv4 firewalling on our devices at work and
> Phillip Smith's talk on 'husk' for firewalling both IPv4 and IPv6 at
> the LCA Sysadmin miniconf  reminded me again that I really need to
> get a proper grip on IPv6.
> So, I followed Adrian Woodley's advice and got an Internode account.
> Internode says I got:
> + A dynamic /64 IPv6 prefix for your PPP session.
> + A static /56 IPv6 prefix for your LAN (if you are using a router
> with Prefix Delegation).
> What's the difference between these two prefixes?
> Adrian's Plug talk on IPv6 could probably answer some of my questions,
> but is still 'private' on youtube.
> 1. http://sysadmin.miniconf.org/presentations14.html#PhillipSmith
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> Committee e-mail: committee at plug.org.au
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