nanog mailing list archives

Re: Failover IPv6 with multiple PA prefixes (Was: IPv6 fc00::/7 - Unique local addresses)


From: Valdis.Kletnieks () vt edu
Date: Sun, 31 Oct 2010 10:22:32 -0400

On Thu, 21 Oct 2010 19:21:41 PDT, George Bonser said:

With v6, while changing prefixes is easy for some gear, other gear is
not so easy.  If you number your entire network in Provider A's space,
you might have more trouble renumbering into Provider B's space because
now you have to change your DHCP ranges, probably visit printers, fax
machines, wireless gateways, etc. and renumber those, etc.  And some
production boxes that you might have in the office data center are
probably best left at a static IP address, particularly if they are
fronted by a load balancer where their IP is manually configured.

"If Woody had gone straight to a ULA prefix, this would never have happened..."

If a site is numbering their internal IPv4 stuff to avoid having to renumber
on a provider change, then why would they number their IPv6 stuff from
provider space rather than ULA space?

And remember - (a) IPv6 allows machine to easily support multiple addresses and
(b) if you have  a provider address and a ULA, changing providers only means
renumbering a *partial* renumber of the hosts that require external visibility
- your internal hosts can continue talking to each other on a ULA as if nothing
happened.

Sure beats the mayhem if your company buys an organization and the 1918
spaces the 2 groups use overlap... Yee-hah. ;)

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