On Mon, 2016-03-07 at 02:57 +0100, Baldur Norddahl wrote: > But the most popular OS (Windows) completely ignores all of that and > makes up an identifier not based on EUI-64. Everyone are happy > anyway. The RFC should have let identifier selection as an > implementation detail as the risk of collision is almost non existent > given a sufficient random selection and we have duplicate address > detection as a safeguard.
Privacy and temporary addresses are two of the three SLAAC types. One critical requirement for the original SLAAC is that the address doesn't change; for devices without writable storage, that requires a deterministic algorithm to generate the address. A further critical requirement was that devices be able to get connected with zero host co nfiguration - globally and locally. For temporary and privacy addresses, where permanence is not an issue, you can use any prefix length, though as I said in my original response, your protection diminishes the longer the prefix gets. I'm not trying to be an apologist for those who designed IPv6, but I really don't think they were stupid, and it's not as simple a situation as people seem to think. My initial response was to someone who said they thought Cisco supported varying prefix lengths with SLAAC. I said it wan't just up to Cisco, the hosts had to play ball too, and I don't think they do. But, as already noted, I could be wrong :-) Regards, K. -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Karl Auer (ka...@biplane.com.au) http://www.biplane.com.au/kauer http://twitter.com/kauer389 GPG fingerprint: E00D 64ED 9C6A 8605 21E0 0ED0 EE64 2BEE CBCB C38B Old fingerprint: 3C41 82BE A9E7 99A1 B931 5AE7 7638 0147 2C3C 2AC4
