Re: [dhcwg] draft-ietf-dhc-dhcpv6-opt-nisconfig-05.txt

[Harald Tveit Alvestrand <[e-mail]>]

Thanks Ted!
The hierarchy you describe seems to make sense to me - and no, I hadn't 
realized that DHCPv6 worked that much differently from DHCPv4.

--On 9. februar 2004 11:19 -0600 Ted Lemon <[e-mail]> wrote:

>> - For "Host specific", make it easy for a host to figure out which set
>> of parameters it uses, and let it stick to that set only. No mixing!
>
> Okay, but how do we specify this?   I guess saying "no mixing" is pretty
> easy, but I don't see how we can go beyond that, and I'm not sure that
> just specifying that is going to result in reliable behavior - it's easy
> to imagine a dumb DHCP client stubbornly making the wrong choice every
> single time.

simple - outlaw dumb DHCP clients :-)
joking aside - you probably need some kind of mechanism to specify that you 
keep on listening to the "same administrator as last time", and mandate 
that a DHCP client has some way to explicitly switch administrators.
This is very similar to what you have to do if you have secure DHCP using 
administrator-related keying.......

>> - Make sure that all "Host specific" parameters are able to specify
>> values that make sense for both IPv4 and IPv6
>
> I'm not sure we've been doing this, but I agree that it's a reasonable
> thing to do.

I'm sure you don't - since that's what the nisconfig DISCUSS was about...

>> - In all the instances I've seen so far, declare that if you need an
>> IPv4 address, put it in as an IPv4-mapped IPv6 address (::12.34.56.78)
>> - no other changes needed.
>
> So are you saying that a DHCPv6 client should be able to acquire IPv4
> addresses, or just that when it gives the addresses of the DNS server, it
> should be able to give the IPv4 addresses as well as the IPv6 addresses?

The latter.

> I can see a lot of problems with the former; in the case of the latter,
> it makes sense, although I would argue that the server administrator
> should be able to enable or disable IPv4 to IPv6 address mapping, because
> I can imagine cases where you'd want it and cases where you wouldn't.

Of course - a v6-only host should know that it can't use a v4 address, no 
matter how it got it. But that isn't much of a pressing problem, 
unfortunately.... apart from special-purpose devices, I think all hosts 
will have to know how to reach a v4 address for many years to come......

>> I may now have repeated a proposal that was suggested and rejected 3.5
>> years ago - that's life too. But you asked......
>
> It's good that you're asking these questions.  I'm sorry for dumping a
> pile more on you, but I am definitely interested in your answers.   We
> needed to kick 3315 out the door, for obvious reasons, but that doesn't
> mean that it requires no further tweaking.   Fortunately, I don't think
> what we're talking about here requires any incompatible changes.

Without knowing too much - I don't think so either - and thanks for 
listening!

                          Harald