Subject: A6 and DNAME

From: "Bernie Volz (EUD)" <[email-masked]>
Date: Mon, 30 Apr 2001 15:58:08 -0500

Hi:

One more item to add to the recent discussion (which I've only partially
followed) on A6 and DNAME records is ... how are they created and used in
the first place?

If one assumes that IPv6 addresses are automatically generated (either using
autoconfiguration or DHCPv6), then how does an A6 record with non-0 prefix
length ever get added in the first place? There hasn't been any method
developed (that I'm aware of) to communicate to a client or DHCPv6 server
that it should register these addresses under a given prefix. Also, if it
were to do this, what happens if the prefix is multi-homed yet the address
allocated to the client isn't (only one of the prefixes is in use)? This
would significantly complicate clients and DHCPv6 servers since they may
have to pull together several addresses before being able to register under
the non-0 prefix? And the failure modes (such as not getting one address
because of DAD or other reasons) are difficult to deal with.

Same happens with the PTR records and DNAME ... how is the client or DHCPv6
server told to use a particular DNAME to register?

Seems to me that most clients and DHCPv6 servers will register with the full
128-bits and therefore this fancy stuff won't be used anyway - since nothing
will be in place to set it up.

Sure, we could add a DHCPv6 option to communicate these details. But, what
about when DHCPv6 isn't used and autoconfiguration is used?

Sorry if this has already been raised as an issue and I missed it.

- Bernie Volz

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From: "Matt Crawford" <[email-masked]>
Date: Tue, 01 May 2001 08:52:47 -0500

> that it should register these addresses under a given prefix.

I don't think draft-ietf-ipngwg-prefix-rr-disc-00.txt has expired yet.
Discussion is in order, although under a new "subject" line, please!