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Re: Important IPv6 Policy Issue -- Your Input Requested

  • From: Iljitsch van Beijnum
  • Date: Mon Nov 15 18:56:44 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.