Windows Server 2008 R2 DNS: A.ROOT-SERVERS.NET Returning Invalid Results?


  • I have two Windows Server 2008 R2 domain controllers which are also DNS servers.  Occasionally, like maybe once every few months, random external sites fail DNS lookup.  Today that was  Lookups succeed in other environments.  We have another environment with Windows Server 2003 R2 domain controllers and DNS servers -- no issues there.  Flushing cache on DNS servers and local boxes does not help.  The only thing that helps is if I remove A.ROOT-SERVERS.NET from the root hints.  If I add A.ROOT-SERVERS.NET back, it fails again.  If I wait a few days and add it back, it works.  So it's intermittent, related somehow to A.ROOT-SERVERS.NET, and only in our one environment on both domain controllers/DNS servers.

    I am thoroughly confused.

    Monday, November 18, 2013 2:15 PM


  • You may need the following hotfixes to resolve this issue. They are not part of SP1. The first two in the list appear to be the ones that more relate to what you're seeing.


    DNS Server service does not resolve some external DNS names after it works for a while in Windows Server 2008 R2
    Hotfix release - (released 4/15/2011)

    DNS Server service does not use root hints to resolve external names in Windows Server 2008 R2
    Post Windows 2008 R2 SP1 HOTFIX available.
    APPLIES TO •Windows 2008 R2 Datacenter •Windows 2008 R2 Ent •Windows 2008 R2 Std.
    Requires a restart.

    Windows 2008 -
    DNS queries for external domains are not resolved when you use Conditional Forwarding in Windows Server 2008
    Post Windows 2008 SP2 Hotfix available
    Requires a restart.
    DNS server stops responding to DNS queries from client computers in in Windows Server 2003, in Windows Server 2008 or in Windows Server 2008 R2 - Post Service Pack Hotfix available.
    Does not require a restart.

    Ace Fekay
    MVP, MCT, MCITP/EA, MCTS Windows 2008/R2 & Exchange 2007, Exchange 2010 EA, MCSE & MCSA 2003/2000, MCSA Messaging 2003
    Microsoft Certified Trainer
    Microsoft MVP - Directory Services
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    This post is provided AS-IS with no warranties or guarantees and confers no rights.

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    Monday, November 18, 2013 5:55 PM

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