Using IPv6 with prefixes shorter than a /64 on a LAN

eric clark cabenth at
Mon Jan 31 23:35:46 CST 2011

Figure I'll throw my 2 cents into this.

The way I read the RFCs, IPv6 is not IP space. Its network space. Unless I
missed it last time I read through them, the RFCs do not REQUIRE
hardware/software manufacturers to support VLSM beyond /64. Autoconfigure
the is the name of the game for the IPv6 guys.

Subsequently, while using longer prefixes is possible currently, I'd never
deploy it because it could be removed from code without mention.

Because of the AutoConfigure  piece, I consider IPv6 to be NETWORK Space,
rather than IP Space like IPv4. I'm issued a /48 which can be comprised of
 65536 /64 networks, not some silly number of hosts, which can't exist
because they are all duplicates of each other (MAC address = host

Anyway, that's how I see the question that started this whole thing, I'd
suggest using link local and RFC 4193 for internal routing and your public
space for things that need public access or need to be accessed publicly.

Just because they SAY there's infinite space (like they said about IPv4)
doesn't mean we have to be stupid and wasteful with our space.

If I've misread, or completely missed an RFC, I apologize.

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