using "reserved" IPv6 space

Wed Jul 18 00:15:17 UTC 2012

In message <5005E87D.6060006 at unfix.org>, Jeroen Massar writes:
> On 2012-07-18 00:21, Seth Mattinen wrote:
> [..]
> > Don't, because there's already a /10 defined for such things. It's
> > called ULA (unique local address) aka RFC 4193. ULAs are not globally
> > routable.
> > 
> > Here's a calculator that will generate a random one for you:
> > 
> > http://bitace.com/ipv6calc/
> 
> A random one indeed, because the javascript for it is just:
> 8<-----------------------------------------------------
>   var calc_private = function() {
> 
>     var str = "fd";
> 
>     for(i = 0; i<10; i++) {
>       str = str + toHex(Math.floor(Math.random()*16));
>       if (i % 4 == 1) str = str + ":";
>     }
> 
>     $("#private_subnet").html("Your private subnet is:
> <code>"+str+":/48</code>");
>     $("#multicast1").val(str+":/48");
>     calc_multicast1();
> ------------------------------------------------------->8
> 
> does not follow RFC4193 in any way at all. A such do not use it.

If you have a true random number source you don't need to use the
method in RFC4193.  The method in RFC4193 is designed to get produce
a good enough pseudo source of randomness.

> The original real RFC4193 ULA generator script can be found at:
>  http://www.kame.net/~suz/gen-ula.html
> 
> google(ipv6 ula) for another page, that has been referenced often enough
> on this very list already, if you want to 'register' it there to avoid
> another small chance of collision, that page also uses the script from
> the above site for a true RFC4193 prefix.
> 
> Greets,
>  Jeroen
> 
-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org