An Exchange UM IPv6 conundrum

Sometimes it happens that there are two distinct and opposite facts presented at the same time… and only one of them can be correct. Here’s a great example:

• The Exchange 2010 SP2 help topic “Understanding IPv6 Support in Exchange 2010” says that Exchange “Unified Messaging doesn’t support IPv6 in any version of Exchange 2010.”
• The Windows IPv6 FAQ says that you should leave IPv6 enabled and present: “From Microsoft’s perspective, IPv6 is a mandatory part of the Windows operating system and it is enabled and included in standard Windows service and application testing during the operating system development process.”

I take this to mean that, from the Windows team’s perspective, IPv6 is expected to be present and functional. From the Exchange viewpoint, UM doesn’t use IPv6 and thus doesn’t care whether or not it is present. I’m not sure that this is 100% correct, but neither the Windows team nor the Exchange team has said anything publicly to clarify the situation. In the meantime, my advice is to leave IPv6 alone; having it enabled doesn’t seem to interfere with the normal function of Exchange 2010 UM.