Domain Controller status is unavailable


This problem was bugging me for a while now. Every time I have to connect to a different DC, status for one of them is showing as “Unavailable” In my case this hasn’t got anything to do with the domain controller actually functioning or having connectivity. DC works fine and I haven’t had any problems with it.

Few screenshots demonstrating the issue as well as explaining what’s the cause:



Solution to this problem (surprise, surprise!) is rather simple. On the domain controller that’s showing as “Unavailable” IPv6 network connectivity is not enabled causing it to don’t report its status. To rectify this we have to re-enable the IPv6 stack under network card properties on the NIC that’s used by the DC. Here is an example:


Generally there is no reason to disable the IPv6 connectivity and it should remain on even if you don’t use it. Explicit cases when you should not disable IPv6 include:

  • If you’re running SBS (aka Small Business Server) 2008 as reported here:
  • When using clustering and configuring heartbeats, these will need to use IPv4 but it makes sense to have it all on IPv6 instead.
  • When DC status shows as “Unavailable”! 🙂
  • 21 thoughts on “Domain Controller status is unavailable

    1. Greg Glenn

      Thanks for the information. This fixed my problem. My AD controller ran out of disk space and I was sure it corrupted the AD Files. After searching I found your post and sure enough the IPv6 was turned off. As soon as the adapter reset it solved the issue. Thanks again.

    2. Arun Sharma

      Hi Adrian Kielbowicz, I am Arun from india i have tried same solution for similar issue with our Domain Controller but still its status is shown Unavailable… can you help on this

    3. Adrian Kielbowicz Post author

      Hi Arun, is the DC actually working properly? Can you connect to it using ADUC even though status shows as ‘Unavailable’?

    4. Q80Warlock

      @Leandro Windows give priority to IPV6 addresses over IPV4, this behavior is default so when a computer tries to query using loopback it automatically uses ::1 instead of for localhost.

      You can reverse the priority instead of disabling IPV6 using registry settings.

    5. Phil Clark

      Any idea what would cause this exact issue but on a 2003 server? I assume that it’s not IPV6 since 2003 doesnt even install that protocal and my other 2003 domains are fine without it installed as well. Any ideas?

    6. Adrian Kielbowicz Post author

      Thanks for stopping by Matt – I’m glad you got your problem(s) fixed! 🙂

    7. Réda BOUTBICHA

      Set-NetAdapterBinding -Name “*” -DisplayName “Internet Protocol Version 6 (TCP/IPv6)” -ComponentID “ms_tcpip6” -Enabled $false
      REG ADD HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters /v DisabledComponents /t REG_DWORD /d 0xff /f

    8. Sreenath Gupta

      You are the man….you nailed it, scratching my head from past 2 days, and the problem is solved now. God Bless you..

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