IPv6 fc00::/7 — Unique local addresses

Jeroen van Aart jeroen at mompl.net
Wed Oct 20 21:48:47 UTC 2010


<IPv6 newbie>

According to http://en.wikipedia.org/wiki/IPv6_address#Special_addresses 
an fc00::/7 address includes a 40-bit pseudo random number:

"fc00::/7 — Unique local addresses (ULA's) are intended for local 
communication. They are routable only within a set of cooperating sites 
(analogous to the private address ranges 10/8, 172.16/12, and 192.168/16 
of IPv4).[12] The addresses include a 40-bit pseudorandom number in the 
routing prefix intended to minimize the risk of conflicts if sites merge 
or packets are misrouted into the Internet. Despite the restricted, 
local usage of these addresses, their address scope is global, i.e. they 
are expected to be globally unique."

I am trying to set up a local IPv6 network and am curious why all the 
examples I come accross do not seem to use the 40-bit pseudorandom 
number? What should I do? Use something like fd00::1234, or incorporate 
something like the interface's MAC address into the address? It'd make 
the address quite unreadable though.

Thanks,
Jeroen

-- 
http://goldmark.org/jeff/stupid-disclaimers/
http://linuxmafia.com/~rick/faq/plural-of-virus.html




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