[ipv6hackers] DAD and Link-Local

Ahmad Sadeh ahmad.sadeh at gmail.com
Fri Jul 13 17:35:46 CEST 2012

The probability that two nodes will generate the same IID is very low.
Actually, it depends on the number of interfaces on the same link.  For
large subnet with one hundred thousand interfaces the probability is less
than 1.7e-8.  I would say it may reasonable to disable DAD as a heuristic
solution to avoid the malicious reply to DAD message.

You can see the draft that estimated the probability of having an address
duplication in a link

Ahmad Alsadeh

On Fri, Jul 13, 2012 at 3:49 PM, <daniel.bartram at bt.com> wrote:

> All,
> After some advice...
> Aware that DAD is performed on link-local as well as global addresses to
> ensure uniqueness, but if the link-local is a randomly generated value, or
> even the IID for that matter, on a P2P link using only link-local
> addresses, what are the chances of those addresses ever matching? In which
> case, can DAD be disabled?
> Dan.
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