Windows Server 2008 r2 and Windows 7 not Resolving Network Names Correctly

Microsoft has forced the adoption of IPv6. Microsoft Windows 2008/2012 servers and applications are heavily dependent on it. If you have disabled IPv6 on a Windows 2008/2012 server (including Windows 2011 Small Business Server) it may take 30-75 minutes before you can logon. IPv6 is critical to Windows Server and its applications, including Exchange. Leave IPv6 on, even unbinding IPv6 from the server NIC results in very slow boot times. This happened to many people who support Microsoft server products so Microsoft released a patch. This patch fixes the slow IPv6 boot time in Windows 7 and Windows Server 2008 and R2 here: http://support.microsoft.com/kb/3014406.

When IPv6 was turned off not only were slow boot times experienced but also local name resolution requests were being sent out to the Internet instead of resolved the local DNS server. It was as though DNS was forwarding all name resolution requests instead of resolving them. The timing could have been coincidental, we aren’t certain. To fix it I installed the above software patch and cleaned up DNS. I removed old A and AAAA entries (and scavenged old DNS records). That worked and local network name resolution is running faster than ever.

The above update was under ‘optional’ for windows 2008 (or 7) without any other additional information in the Windows update console. From this experience I think this should be a required patch, not an optional one.

2015 Update: IPv6 is key to Windows running smoothly so I recommend leaving IPv6 on. We’ve been seeing DNS preferring IPv6 name resolution over IPv4. In larger environments detailed planning is required but in less than 250 employee corporate networks, leave it on as Microsoft is not going back to preferring IPv4.

mpasatieri posted at 2014-12-20 Category: OS, Server Support