Subject: DNS discovery discussion

From: "Jaehoon Jeong" <[email-masked]>
Date: Fri, 18 Jul 2003 09:42:58 +0900

Hi IPv6 members.

As it seems that the discussion of DNS discovery is related to IPv6 wg, I send 
this issue to IPv6 wg for listening to IPv6 members' liberal opinions and
comments.

In this DNSOP meeting and mailing list, RA-based DNS discovery has been
being discussed in comparison with DHCP-based DNS discovery.
You can find the mails related to this issue in the following link;
 http://www.cafax.se/dnsop/maillist/2003-07/maillist.html

For consistent and time-saving autoconfiguration, I think, we need to adopt one of
two alternatives in sequence (stateless and stateful approaches). In IPv4 domain, 
DHCP is enough for the autoconfiguration. But, in IPv6, we introduced 
stateless autoconfiguration.

Like Tim's opinion, DNS information is missing in the current IPv6 stateless autoconfiguration. 
Of course, DHCPv6 is a good solution. However, in order to get only DNS information, 
it is so limited direction for all kinds of IPv6 networks, such as home network, 
HMIPv6, NEMO and MANET connected to the Internet, to adopt only DHCPv6-based 
DNS discovery. IMHO, RA-based DNS discovery is a really really good companion 
with DHCP approach, not enemy or competitor.

Just in order to announce DNS information, isn't to run  DHCPv6(Lite) overactive? 
RA-piggyback announcement of DNS information with prefix information is efficient 
in the respect of the amount of announced traffic.

In current Cisco router, we configure the addresses of recursive DNS servers for its own name resolution.
Therefore, the DNS servers' addresses have already been configured. We only have to use the information
so as to announce DNS information through RA message.

I think DNS discovery is indispensible in IPv6, as you know. RA camp including me continues to appeal
the need of RA-based DNS discovery for IPv6 working more flexibly even in the environment 
where there is no DHCPv6.
If many of IPv6 members think that RA-based DNS discovery is not necessary, there may be no reason to
discuss any more and the RA-based DNS discovery should not be suggested forever.

I wait for your liberal and frank criticism or opinions.

/Jaehoon Paul

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From: Alain Durand <[email-masked]>
Date: Fri, 18 Jul 2003 01:07:08 -0700

This discussion has been going on in the v6 wg for a while without 
success,
it is now to dnsop, let's go there and hope we'll make progress.
no need to crosspost, IMHO.

	- Alain.

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From: "Jaehoon Jeong" <[email-masked]>
Date: Fri, 18 Jul 2003 10:20:12 +0900

That's Okay.
I appreciate your previous work related to DNS discovery until now.
I really hope we'll solve the issue successfully.
Thanks.

Jaehoon Paul

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From: Alain Durand <[email-masked]>
Date: Fri, 18 Jul 2003 01:20:19 -0700

> so as to announce DNS information through RA message.

You could do the very same thing using DHCPv6-lite. The information is 
there,
it is flowing from the router to the node downstream, in a push or pull 
mode.
It really is just a question of packet format. Using the multicast 
extension
to DHCPv6-lite I suggested few days ago, there isn't really any 
difference
between the 2 approaches with regard to pass the DNS recursive server 
address.
The advantage of the DHCPv6 approach is that you can pass other 
configuration
information, like the address of the NTP server.

> where there is no DHCPv6.

The RA camp keeps making the false assumption that using the 
DHCPv6-lite protocol to do this
requires to have a big-iron DHCPv6 server on the network. This simply 
is not true.

	- Alain.

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From: Pekka Savola <[email-masked]>
Date: Fri, 18 Jul 2003 11:58:00 +0300 (EEST)

On Fri, 18 Jul 2003, Alain Durand wrote:
> there, it is flowing from the router to the node downstream, in a push
> or pull mode. It really is just a question of packet format. Using the
> multicast extension to DHCPv6-lite I suggested few days ago, there isn't
> really any difference between the 2 approaches with regard to pass the
> DNS recursive server address. The advantage of the DHCPv6 approach is
> that you can pass other configuration information, like the address of
> the NTP server.

1) spec complexity
2) implementation complexity (there _may_ not be that huge a difference 
here, but probably some)

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings

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From: Bob Hinden <[email-masked]>
Date: Fri, 18 Jul 2003 03:10:36 -0700

Alain,

>You could do the very same thing using DHCPv6-lite. The information is there,
>it is flowing from the router to the node downstream, in a push or pull mode.
>It really is just a question of packet format. Using the multicast extension
>to DHCPv6-lite I suggested few days ago, there isn't really any difference
>between the 2 approaches with regard to pass the DNS recursive server address.
>The advantage of the DHCPv6 approach is that you can pass other configuration

I think you are suggesting extending DHCPv6-lite to have all of the 
mechanisms that ND currently has for sending multicast advertisements.  I 
don't think this is quite a simple as you suggest.  This seems to me like a 
lot of extra complexity and changes DHCPv6-lite from what I understand to 
be is a "profile" on the DHCPv6 specification.   This would be either a new 
protocol or a non-trivial change to DHCPv6.  This doesn't seem like a good 
way to proceed to me.

Bob

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From: Michael Richardson <[email-masked]>
Date: Fri, 18 Jul 2003 13:07:06 +0200

-----BEGIN PGP SIGNED MESSAGE-----

>>>>> "Bob" == Bob Hinden <[email-masked]> writes:
    Bob> I think you are suggesting extending DHCPv6-lite to have all of the
    Bob> mechanisms that ND currently has for sending multicast
    Bob> advertisements.  I don't think this is quite a simple as you

  I agree with Bob, this isn't the way to go.
  If, the IP that you put into the RA is the address of the DHCPv6-lite
server, then you can ask *it* about the DNS server. (Getting the local domain
name, print server, boot server, etc... that you might need)

]                   At IETF57 in Wien, Austria                  |  firewalls  [
]   Michael Richardson, Sandelman Software Works, Ottawa, ON    |net architect[
] [email-masked] http://www.sandelman.ottawa.on.ca/ |device driver[
] printk("Just another Debian GNU/Linux using, kernel hacking, security guy");[

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From: Michael Richardson <[email-masked]>
Date: Sun, 20 Jul 2003 11:06:42 -0400