[ipv6hackers] DAD and Link-Local

Marc Heuse mh at mh-sec.de
Sat Jul 14 10:05:44 CEST 2012


dont nail me to that, but I remember that the rfc says that DAD has to
be performed everytime, for manual, SLAAC and dhcp address configuration.

they can all conflict, my chance or by mistake.

the chances of conflict are slim, but ipv6 tries not to work 99.99% of
the time but 100% :-)


Am 13.07.2012 20:35, schrieb Owen DeLong:
> DAD can be disabled if you are sure that there is no chance of collision.
> 
> With randomly chosen IID, you're not sure, but it's highly unlikely.
> 
> With MAC-based IID, you can check once and be sure until the hardware changes.
> 
> On a point-to-point link disabling DAD is probably harmless even if there is a collision.
> 
> Owen
> 
> On Jul 13, 2012, at 6:49 AM, <daniel.bartram at bt.com> <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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> 
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