We use BIND for our DNS, and allow certain systems to perform dynamic DNS registration. This arrangement has worked well for years. When I started deploying Server 2008 R2, I noticed that they werenâ€™t registering PTR records.
At the same time, I noticed a bunch of errors that seemed to indicate that Dynamic DNS wasnâ€™t working at all. It turns out this is a false error, due to the differently formatted, but still correct, success message returned by the BIND DNS. (see KB977158 for details)
After spending lots of time doing packet captures (thanks for your help, Sam!), I opened an issue with Microsoft. After collecting a few traces to analyze, they determined that the same differently formatted success message was responsible.
I installed the KB977158 hotfix, and now my Server 2008 R2 hosts are successfully registering their PTR records.