It’s interesting to hear feedback from the SBS support team at Microsoft in Las Colinas, TX about the issues that they see when supporting the product. One of the common ones that they see, and I hear out there in the community is around IPv6 being evil or bad on SBS 2008. Some people experience connectivity issues on SBS 2008 (and potentially SBS 2011) ad they do some googling. They find “similar” issues where others not on SBS have disabled IPv6 and it’s resolved it. However when they go to disable IPv6, they just remove the tick from the binding of the protocol on the Network card – this is not good enough. This does NOT properly disable IPv6 at all.
What I think they fail to do is to use the inbuilt SBS 2008 “Fix My Network” wizard that is on the Network tab of the SBS 2008 console. This wizard would in most cases find and resolve most connectivity issues that users themselves have often caused.
If you MUST disable IPv6, then do it correctly. You can find documentation on how do disable IPv6 correctly here on the SBS team blog.