On Tue, 2005-03-15 at 21:02 -0500, Michael Banta wrote:
>Hello.
>
>New to ipv6, have read a lot, still confused...
<SNIP>
>Should the /48 block actually be a 2002: block to be a compatible 6to4 
>address?  If so, why would Hurricane Electric give me a 2001: prefix 
>unstead of a 2002?

Check this picture:
http://unfix.org/projects/ipv6/IPv6andIPv4.gif

You are the bottom left computer. You have native IPv4 and a proto-41
tunnel to a 6in4 router (Hurricane Electric).

If you thus want to send traffic to other IPv4 hosts they go through the
blue IPv4 cloud, where a lot of routers are and take care that the
packets get delivered. If you want to talk to IPv6 hosts, the packets
get sent to Hurricane Electric's router, which is connected to the red
cloud, which takes care that it gets sent to the correct endhost.

If you thus want to send a packet to a 6to4 host (anything in 2002::/48)
the HE router will send it into the red cloud and the red cloud will
send it on to a 6to4 relay, which will deliver it to the 6to4 host.

See the current assignments here:
http://www.iana.org/assignments/ipv6-unicast-address-assignments

It does not really matter where you are in this list, the routers will
take care of delivery of packets.

That said, it _could_ be useful to setup a 6to4 relay your own, but this
can cause problems because you actually are using non-6to4 addresses,
security issues. Avoiding 6to4 is generally a good idea. 6to4 in general
should only be used if you need a temporary address and don't really
care about quality or reachability IMHO. The number of relays is fairly
limited and debugging the traffic is quite difficult caused by
asymmetric paths and other nastyness.

>This is so confusing.

Then I hope my short explanation helped a bit ;)

Also, if you have eth0 for instance, you should announce a /64 on that
wire, not the /48, which is comprised of 65k /64's.

Greets,
 Jeroen

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