According to Google, Internet Protocol version 6 (IPv6) will be permanently enabled for all Google Apps on June 6, 2012. For most information technology professionals and administrators using Google Apps, this is not a major problem, but there are bound to be a few organizations with systems that aren’t completely ready for the new standard.
The Google announcement notes:
Customers with SSO IP Whitelists and IPv6 capable equipment need to ensure that their SSO whitelist configuration contains their IPv6 network segments (if applicable).
So, are you ready for IPv6? Are you sure?