I know C|Net is not so popular here... but this article was interesting: I had forgotten that XP does not support IPv6. For that matter, I'd turned it off and stopped thinking about it long ago on my macs as well. Although I guess when I upgraded to Tiger and when I got my iMac, I may have gone back to auto IPv6. I'm certainly aware that it will eventually be necessary. Do most people have it turned on or off (for performance enhancement because it is not necessary)?