An introduction to IPv6 can be found on the following website:
IPv6 is still not in widespread use across intranets and the Internet at large. For that reason, it is recommended that unless you require IPv6 in your environment; turn off IPv6 before you begin your Sametime install or migration to version 8.5.2.
If you must use IPv6 networking, note that some components of a Sametime server require the use of an IPv4-formatted loopback address. Therefore, to insure that your servers function without potential network issues, do not disable IPv4. Be sure to run both IPv4 and IPv6 addressing.
As stated previously, IPv6 addressing ...