Subject: Q on DHCPv6 draft (draft-ietf-dhc-dhcpv6-15.txt)

From: Indrajanti Sukiman <[email-masked]>
Date: Tue, 19 Sep 2000 15:12:49 -0700 (PDT)

In the draft-ietf-dhc-dhcpv6-15.txt, in sections related to message
validation (section 11.1, 11.2, 11.3), there are 'MUST' requirements that
agents (server and relay) discard messages which do not contain a 'valid
link-local address'. 

My question is, what is the definition of 'a not valid link-local address'?
Or, in other words, how would agents perform this verification ?
As far as I can tell, RFC2462 defines an invalid link-local address as an
address whose valid lifetime has expired. If this is the definition
intended, is there a way e.g. for a DHCPv6 server to know the valid
lifetime of the link-local address of a remote (several hops away) DHCPv6
client ? 

Thank you. 

-- Indrajanti Sukiman

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From: Richard Johnson <[email-masked]>
Date: Tue, 19 Sep 2000 15:30:32 -0700 (PDT)

> lifetime of the link-local address of a remote (several hops away) DHCPv6

I feel sure what's meant is the definition from rfc1884.txt:

   2.4.8 Local-use IPv6 Unicast Addresses

   There are two types of local-use unicast addresses defined.  These
   are Link-Local and Site-Local.  The Link-Local is for use on a single
   link and the Site-Local is for use in a single site.  Link-Local
   addresses have the following format:

    |   10     |
    |  bits    |        n bits           |       118-n bits           |
    +----------+-------------------------+----------------------------+
    |1111111010|           0             |       interface ID         |
    +----------+-------------------------+----------------------------+

   Link-Local addresses are designed to be used for addressing on a
   single link for purposes such as auto-address configuration, neighbor
   discovery, or when no routers are present.

   Routers MUST not forward any packets with link-local source
   addresses.

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From: Indrajanti Sukiman <[email-masked]>
Date: Tue, 19 Sep 2000 16:03:46 -0700 (PDT)

So, given this, I conclude that the check at the agents whether or
not the link-local address is valid or not valid, would be as
trivial as checking the prefix of the link-local address is the well-known
FE80::0 prefix ?

-- Indrajanti Sukiman