Exchange 2007 SP1 has support for IPV6 under certain circumstances. http://technet.microsoft.com/en-us/library/bb629624.aspx
Since most people don’t use IPV6 on there’s network I suggest that you disabled it (it cannot be uninstalled). This is done in 3 steps.
· Uncheck the IPV6 checkbox on your NIC settings.
· Edit the hosts file and disable the line “::1 localhost”, that is put a # sign at the front.
· And the last thing is to do is edit a registry value. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters\DisabledComponents and put in a DWORD with value of 0xffffffff
This will turn off IPV6 for everything except the loopback traffic and Exchange does not have an issue with that. For more ref. see http://support.microsoft.com/kb/929852
You have to reboot your server after editing this registry value.
Doing all this will also resolve some other issues, the most famous one is the problem with RPCProxy component only listening on IPV4 and make Outlook Anywhere work again.