Subject: v6 (was Re: -current sendmail cancer in IPv4-only kernel)
To: None <>
From: Perry E. Metzger <>
List: current-users
Date: 05/08/2000 09:46:19
Greywolf <> writes:
> I have a serious question for the v6 pundits.  If we DON'T go to IPv6,
> we run a serious risk of actually running out of IP addresses.  Are
> we going to turn to bi-level NAT, or N-level NAT, or are we going to
> do something _sensible_?

The only thing you *can* do is N level NAT, and it doesn't work very

> I'm not clue-enabled about ipv6 currently, but I'm trying to learn it.

There is really very little to learn. Here are the differences, in a
few lines:

1) Addresses are 128 bits instead of 32 bits.
2) There is a bunch of goo that replaces most of the local link
   protocols (i.e. arp & friends) called "neighbor discovery" that
   uses IP multicast instead of depending on another "out of band"
3) In general, the last 64 bits of address are reserved for local
   stateless autoconfiguration on your LAN, although I do not
   recommend actually using the stateless autoconfiguration
   facilities, having now used v6 for a while.
4) In order to allow local systems to talk for purposes like
   autoconfiguration and neighbor discovery without already having
   configured addresses, there are now "link local" addresses which
   are really just addresses guaranteed not to go off the LAN that are
   used much like MAC addresses, although technically they are v6
6) Oh, and the packet format is cleaner.

A skilled admin can learn everything they really need to know to
configure a v6 lan in the space of 20 minutes at most, and literally
*everything* there is to know about v6 in the space of a few
hours. The protocol just isn't that different. TCP is still TCP. IP is
still IP.

> What we could stand is someone like Cisco or Nortel, one o' them Big
> Gunnish type guys, to come out with routers and switches which handle
> IPv6 natively.

They do already. The latest Nortel firmware handles v6, and Cisco is
now starting to ship v6 production firmware for many of their routers.

Perry Metzger
"Ask not what your country can force other people to do for you..."