[6bone] ifconfig and EUI-64

[Robert Elz]

    Date:        Wed, 12 Jun 2002 14:07:56 +0200
    From:        Francis Dupont <Francis.Dupont@enst-bretagne.fr>
    Message-ID:  <200206121207.g5CC7uT06279@givry.rennes.enst-bretagne.fr>

  | => no, for instance in KAME you have to recompile the kernel with
  | "options IP6_AUTO_LINKLOCAL=0"...

Then what you mean isn't what you said, I use KAME, and I have lots
of link local addresses, and I never knew that option existed.

I suspect that what you mean is "not automatically generate a link
local based upon the IID" but that's a different thing to
"explicitly set the link local address".

  | => on a reasonable system to set the link-local address or the IID are
  | equivalent.

Only if you make the assumption that there is only one link-local address.
That's not a reasonable assumption I don't think.   There's no reason not
to have several.

eg: In general I prefer regular auto-config'd addresses (EUI-64 and all
that in the IID).   But for debugging (ping of the address, etc) it is
nice if they also have nice easy to use LL addresses, like fe80::1 fe80::2
and such, so I just go assign those.   It can also be convenient to have
fe80::a.b.c.d where a.b.c.d is the IPv4 address assigned to the interface,
as that's then a real easy way to match things, and know which is which
(from the ancient past, I tend to simply know what IPv4 addr applies to
every system around).

But I want only one IID for the interface - which one of those should
the kernel pick, if it was to treat them as equivalent.

  | => the subject of this thread is the extension of this to the ifconfig
  | command.

Yes, I know, what I would like to be able to do is

	ifconfig interface inet6 iid 77

and if I do that before anything else has enabled IPv6 on the interface,
it should simply use "77" (which would be a hex string with an arbitrary
number of :'s up to 5, with an implied (maybe required explicit) leading ::)
when it first enabled the interface and configures its first link local.

Being able to specify "prefix xxx::" I would also like.   The "iid" is
mostly for hosts, "prefix" for routers (iid for routers too, but specifying
both iid and prefix is just the same as specifying the whole address on
a router, which doesn't get more prefixes from RAs).

kre