IPv6 Addressing Help

David Freedman david.freedman at uk.clara.net
Fri Aug 14 10:49:30 CDT 2009

Chris Gotstein wrote:
> I think we had to let ARIN know the time frame of deploying IPv6 and how
> many customers we expected to put on in the first couple years.  They
> did not ask for an addressing scheme.
> Reading over the RFC's and other IPv6 resources, we have decided to hand
> out /56's to small/home/SOHO customers and /48's to larger customers.
> I'm just not able to wrap my brain around the subnetting that needs to
> be done on the router.  Like i said before, i think i'm just over
> complicating it in my mind.

Will keep it simple, this is what I (and I suspect many others) do

/128 - Loopback (what else?)
/126 - Router p2p
/112 - Router LAN shared segments (p2mp)
/64  - Single customer LAN segments (customers asking for basic IPv6)
/56  - Customer wants multiple LANs, doesn't want to fill out
justification form
/48  - Customer wants multiple LANs, thinks /56 is too small (for some
reason), needs for routing, wants rDNS delegation etc.etc.etc..

This question gets asked so many times now, whilst people argue about
the implications of using networks smaller than /64 for anything
such deployments continue to exist and are successful.

Perhaps we should document people's addressing plans somewhere, I
see ratemyaddressingplan.com hasn't been taken yet? :)


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