Subject: IPv6 and Dynamic DNS

From: Robert Elz <[email-masked]>
Date: Tue, 03 Aug 1999 01:19:45 +1000

In a message on the ipng list that reminded me I wanted to send this,
Ray LaRocca said of the UNH IPv6 test suite ...

  | 3. Dynamic Updates to DNS for IPv6

Ppeaking of which, has anyone given any thought to how dynamic DNS
update is going to be made to work for the IP6.INT domain?  (That is,
for the reverse translation).

With IPv4, dynamic addresses come only from DHCP (or PPP servers or
similar), and the assumption generally is that the the dhcp server
(or whatever it is which assigned the address) has the necessary relationship
with the in-addr.arpa zone file to have the authorityo to be able to
perform an update.

On the other hand, for the forward transmation (name -> address) it can
be either that server, or (I believe) more likely, the node itself which
has that authority (the node gets a name from somewhere, if the name comes
from the dhcp server, then the dhcp server has the authority, if the name
was provided some other way, then the authority can be provided along with it).

For IPv6 there is normally no such server - nodes create their own IPv6
addresses (from information multicast by routers .. this explanation is for
the benefit of namedroppers recipients).

But there is not necessarily any relationship at all between the node and the
network on which it is located.   Eg: in Oslo at the IETF I was using IPv6,
my laptop assigned itself an address (quicker than it ever managed to get an
IPv4 address from the dhcp server - and there weren't any noticeable delays
there either), but my laptop certainly didn't have permission to update the
relevant IP6.INT zone file, and there was nothing else other than the laptop
that knew what address it assigned to itself (unless someone was snooping on
the DAD packets - which in this case they probably were, but which isn't
normally to be expected).

I could have easily had the laptop update the forward zone file (I didn't,
but that's a separate issue) with its current IPv6 address, but how would
I have gone about updating the reverse translation?

kre

---

From: Dean Anderson <[email-masked]>
Date: Tue, 10 Aug 1999 17:58:06 -0400

It is usually tomslaptom.someoneelse.com.  At least, it has been in the
last 20 or so companies over the last 4 years that I've plugged into with a
travelling laptop. You get your connectivity from them. They give you a
name to use, too. 

But clearly this is a potential application for dynamic update.  My
emphasis on Potential.  DNS gives you functionality without policy.  You
define policy.

Since you own mycompany.com, you control its update and whether you do
dynamic update.  So the machine could potentially have 2 names, and its
quite likely that its reverse DNS will be off, but consistent enough for
applications like mail.  Especially if mycompany.com does dyn update and
someoneelse.com or their ISP doesn't.

And the laptop name often doesn't include the domain name, at least for MS
machines.  Remember the bad update thread of several weeks/months ago where
the desktop updates DNS with the same name as a server.

		--Dean

Around 12:04 PM 8/10/1999 -0700, rumor has it that Terry Lambert said:
>Tom Limoncelli wrote:
>> 
>> I have a really dumb question about all this.
>> 
>> Consider this situation:
>> 
>> My laptop is tomslaptop.mycompany.com.
>> 
>> I visit SomeoneElse, Inc. and plug my laptop into their
>> network and use autoconf or DHCPv6 to get an address.
>> 
>> What should I expect as my FQDN?  Is it tomslaptop.someoneelse.com
>> or should I expect the right DNS updates to maintain my name as
>> tomslaptop.mycompany.com.
>
>Unless you sold your laptop to SomeoneElse, Inc., I think
>it should retain its True Name (emphasis intentional).  That
>is, it should remain tomslaptop.mycompany.com.
>
>While most of the paranoia on this question ("the travelling
>laptop problem") has been directed to "protecting" your DNS
>from containing reverse mappings for addresses that are in
>your zone of responsibility (and which you are routing),
>there is a real issue with your laptop being fooled into
>sharing its resources (including its network accessible
>filespace) with other machines at SomeoneElse, Inc..
>
>I think that this _requires_ that your laptop retain its
>True Name.
>
>
>> Note: I'm not asking about reverse lookups.  Depending on the
>> answer to the question above I have different questions about
>> reverse lookups.
>
>Probably the same as my question, only I assumed the above
>as a posit, when maybe I should have stated it as an assumption,
>like your question does.  8-).
>
>
>-- Terry Lambert
>-- Whistle Communications, Inc., an I.B.M. Company
>-- [email-masked]
>-------------------------------------------------------------------
>This is formal notice under California Assembly Bill 1629, enacted
>9/26/98 that any UCE sent to my email address will be billed $50
>per incident to the legally allowed maximum of $25,000.
>
>
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