nanog mailing list archives

Re: using "reserved" IPv6 space


From: Brett Frankenberger <rbf+nanog () panix com>
Date: Sun, 15 Jul 2012 10:28:50 -0500

On Sat, Jul 14, 2012 at 09:48:49PM -0400, Robert E. Seastrom wrote:

Actually, that's one of the most insightful meta-points I've seen on
NANOG in a long time.

There is a HUGE difference between IPv4 and IPv6 thinking.  We've all
been living in an austerity regime for so long that we've completely
forgotten how to leave parsimony behind.  Even those of us who worked
at companies that were summarily handed a Class B when we mumbled
something about "internal subnetting" have a really hard time
remembering how to act when we suddenly don't have to answer for every
single host address and can design a network to conserve other things
(like our brain cells).

Addresses no longer being scarce is a significant shift, but this
thread is about a lot more than that.  I didn't get the feeling that
the original poster was wanting to use non-global addresses on his
internal links because he was concerned about running out.  He also
wanted to do so for purposes of security.

And that's not a paradigm shift between v4 and v6.  Obscurity /
non-global address "magic" was pretend security in v4 and it's pretend
security in v6.  People who used RFC1918 space where they didn't need
global uniqueness in v4 often did so initially because of scarcity (and
were often making a completely reasonable decision in doing so), but
they then falsly imputed a security benefit to that.  

If we can leverage the v6 migraton to get out of the thinking that some
addresses are magically more secure than others, then that's probably a
win, but it's not a fundamental difference between v4 and v6.  It's not
that correct IPv4 thinking is "1918 is more secure" but the security
model of v6 is different.  1918 was never more secure.

     -- Brett


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