Renumbering with IPv6 WAS: [ppml] Get you IPv6 Today,

Mury mury at
Wed Jan 8 17:41:10 EST 2003

I shouldn't be the one answering this because I have no experience with
IPv6, but it seems that half of this discussion could be eliminated by
someone taking the time to explain how DNS and IP numbering takes place
with IPv6.

I will give it my best shot since no-one else has stepped up to the plate.

Renumbering with IPv6 should be relatively painless.  Within your block of
IPs you will number your systems (actually interfaces) with IP suffixes.
Whether you do that with static IPs or with something similiar to DHCP it
doesn't matter.  The prefix to the IPv6 address would be learned from your
router or a provider's router.

Thus to renumber you would only need to get the new IPv6 prefix from your
new ISP.  Yes, you would need to change a static route or two here and
there and put the new suffix into the router to be learned by the hosts
but it doesn't sound like much work.

Very simplified example:

Let's say an IP is 4 digits.  You configure your router with the prefix of
your ISP "56" and the suffix you want to give it "10".  So the routers IP
is 5610.  Then you would configure your hosts (interfaces) with suffixes.
Let's say you give 15 to a host.  You also tell that host to look to IP 10
to get the prefix.  The host then learns that it's full IP is 5615.

So you change ISPs.  In the router you put in it's new IP 7810 where 78 is
the new ISPs prefix.  You also tell the router to tell hosts that the IP
prefix is 78.  You add a static route back to the ISP from the router.
Everything else on the internal network can be left untouched.  The
previous host in question automatically changes it's IP from 5615 to 7815.

This will bring up a question of DNS.  With IPv6 DNS will work much the
same way.  Not only with a simple config change will it correctly renumber
all your IPs, but it will also let you translate both IPv4 and IPv6 IPs
for the same host.

As a mentioned I have no experience with IPv6, but this discussion seems
to be getting no where and I figured I should give it my best shot.  Feel
free to correct any false information.


 On Wed, 8 Jan 2003, Phil Howard wrote:
> | What space is permanent? No IPv6 space is "permanent" in the sense
> | that you will be guaranteed to always have it and that it will always
> | be routable. If you are an endsite, your ISP might fold and the
> | addresses might stop working.
> That can happen.  That's why I want permanent addresses, to avoid that.

More information about the ARIN-PPML mailing list