Most of the organizations are using IPv4 in their networks. IPv4 is a 32-bit address and the format is A.B.C.D. (like 192.168.0.1). Since IPv4 addresses are very limited, so IPv6 overcome this issue by offering 128-bit address support. Exchange Server 2007 and Exchange Server 2010 support IPv6, but this environment will only exist with IPv4. If we disable IPv4, then Exchange Server will not support IPv6.
Exchange Server 2007 Service Pack 1 and Service Pack 2 supports IPv6 only when it is installed on Windows Server 2008 and both, IPv4 and IPv6 are installed on the same system. Same rule also applies with Exchange Server 2010.
In Windows Server 2008, IPv4 and IPv6 are installed and enabled by-default. We can remove IPv4 and have only IPv6 native environment. IPv6 is not installed by default, in Window Server 2003. We can install IPv6 in Windows Server 2003, but it is fully dependent on IPv4, which means we can’t uninstall IPv4 if IPv6 is installed.
If we install Exchange Server 2007 on Windows Server 2008, then lots of components are dependent on IPv6 and so it must be enabled. Simply leave the default IPv6 setting (Obtain an IPv6 address automatically) and run the Exchange Server 2007 setup.
You will also get an error when you will try to install Exchange Server 2010 Hub Transport role without IPv6.