Re: 64bit MAC addresses and SLAAC

[Philip Homburg <[e-mail]>]

> We looked for the place in linux which forces the 64bit limit in
> SLAAC.

Which make sense, because that is what the RFC says.

>   We found it and we wondered what to put in these - potentially
>   66 - bits of an IID?   The immediate thought was to put there
> random numbers.
>   These random numbers seemed natural to several of us.  And they
>   offer privacy.

I'm sure that if SLAAC is updated to allow other lengths, some consideration
will be given to generating IIDs. However, at the moment SLAAC is 64-bit
even if some implementations try to be more flexible.

> If we put random numbers in there then for years again the users
> will find it difficult to remember those scrambled numbers when
> typing ifconfig.

That is the nature of SLAAC. You need an IID that has a very high probabily
of being unique. So you need enough random bits.

If you want easy to remember addresses, go for DHCPv6.

> If we put random numbers in there then for years again people will
> look for easy to use, license-free, platform-independent, high
> performance, speedy, C standard, less energy consuming, almost-true
> random, primitives to call; and their seeds.

It is not to hard to find an SHA2-HMAC implementation.