In message <43791C64.4050500@linuxbox.org>, Gadi Evron writes:
You don't have to scan an entire /64 ( :) ).
You can sniff network traffic and see what IP addresses you see, then scan only close ranges to those. You can create a DB or download one, with addresses of known used spaces.
You can throw out thousands of random packets, finding used spaces.
You can do a lot of things, some smarter and mathematical, others just sensible. If I could come up with 3 silly solutions in 2 seconds, I bet the Bad Guys will do far better when the time comes, if it ever does. I am of a mind that we need IPv-NEXT-ONE (or whatever) to deal with actual problems before we undertake IPv6, but that's just an opinion and therefore completely wrong.
Yes. Angelos Keromytis, Bill Cheswick, and I have a paper on this that will be out shortly. --Steven M. Bellovin, http://www.cs.columbia.edu/~smb