In working on a customers AD and DNS upgrade to Windows Server 2008 R2 we discovered an interesting problem relating to EDNS. After configuring the forwarders on the new DNS server we found we were unable to browse the internet from those machines. A quick search turned up <a href="http://social.technet.microsoft.com/Forums/en-US/windowsserver2008r2general/thread/1b0b16b0-9372-4027-8aeb-911a98d64ef4">this article</a> on Technet. Turns out the fix is a simple command:

dnscmd /config /EnableEDNSProbes 0

No restart or service bounce required and we were immediately able to browse the internet.

A deeper explanation is available <a href="http://weblogs.asp.net/owscott/archive/2009/09/15/windows-server-2008-r2-dns-issues.aspx">here</a>.<strong>
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