If you aren’t aware, Vista and Server 2008 have fully baked in support for IPv6 right out of the box. No amount of unchecking the IPv6 boxes on your NIC will fully disable all of the IPv6 features.
Why would you want to disable IPv6? Exchange Server 2007 SP1 has many known issues with IPv6 and so I recommend fully disabling IPv6 to avoid any issues. Even the mere presence of IPv6 on your server causes Exchange to bind to services differently, which may cause you headaches.
Towards the end of this article, Technet shows you the registry change needed to fully and completely turn off IPv6. But the trick is, WHEN do I disable it? Before I install Exchange, after, during? How about CCR cluster configuration and IPv6?
As it turns out, the Server 2008 cluster configuration tool appears to need IPv6 available during the configuration process even if your network is entirely IPv4. Why? Beats me, but the Failover Cluster Configuration tool will hang and produce an error if you use the 0xffffffff trick prior to configuring the cluster.
So my recommend order for installing a CCR cluster is:
1. Configure heartbeat and production NICs according to best practices and leave IPv6 enabled.
2. Configure the Server 2008 Failover cluster for your CCR nodes and verify all NIC resources are online and available.
3. After a successful cluster configuration, follow the steps in the article above to disable IPv6.
4. Re-test your failover cluster to verify all resources are online.
Pretty simple, but may save you some troubleshooting time if you disable IPv6 prior to the cluster configuration and fail miserably!
