Important IPv6 Policy Issue -- Your Input Requested

Iljitsch van Beijnum iljitsch at muada.com
Mon Nov 15 23:53:51 UTC 2004


On 15-nov-04, at 23:10, Adi Linden wrote:

> Aren't unique site locals associated with the mac address?

Not really. Unique site local addresses as such don't have anything to 
do with MAC addresses. However, most IPv6 addresses (including, 
presumably, unique site locals when they are deployed) contain a MAC 
address in the bottom 64 bits. This happens when stateless 
autoconfiguration is used: routers broadcast (well, multicast) the top 
64 bits and hosts fill in the lower 64 bits with a unique value. This 
was the MAC address (if available) until privacy advocates came along 
and now there is also RFC 3041 which uses random numbers for this.

Note though that it is by no means required to use stateless 
autoconfiguration: you can set the address(es) manually, or you can use 
DHCP for IPv6. Also note that (AFAIK) of the major OSes and out of the 
box, only Windows supports RFC 3041, and Windows and MacOS don't (yet?) 
come with DHCPv6 support, and it doesn't look like it's easy to add it 
yourself (like in the *nix world) either.




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