Background: I have a windows 2008 machine and I want to make it a Domain Controller in a test domain made of two virtual machines. dcpromo pops up a warning if IP addresses for the machine are not statically configured. Disabling IPv6 is not an option since it's required by Exchange, which in turn is a prerequisite for the software I must test.

The question: How should I configure the IPv6 properties of the network adapter to use a static ipv6 address? what is the "ipv6 equivalent" of a static 192.168.x.x ipv4 address?

  • Where did you read IPv6 is required by Exchange? Never heard such a thing before. Which version of Exchange, BTW? 2003 and 2007 both runs fine without IPv6; I don't know for 2010 beta, but I'd be quite surprised if it actually required IPv6, as opposed to just supporting it.
    – Massimo
    Sep 25, 2009 at 17:05
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    What do you mean by "Disabling IPv6 is not an option since it's required by Exchange"? Exchange doesn't require IPv6 at all, it merely supports it (and only using Exchange 2007 with Windows Server 2008).
    – Massimo
    Oct 2, 2009 at 22:42
  • You are right that it's not required but if you try to install Exchange 2007 SP1 on a Windows 2008 server then you will get grief unless you either completely disable IPv6 or you configure it to some basic level. simply unbinding it from the network adapter(s) will cause failures - see here: msmvps.com/blogs/ehlo/archive/2008/06/12/1634433.aspx
    – Helvick
    Oct 3, 2009 at 0:08
  • I installed Exchange 2007 on a Windows 2008 server in August, and I disabled IPv6 on the network adapter, but I didn't make that Registry change (I didn't even know about it until now); nevertheless, Exchange has been up and running for a while...
    – Massimo
    Oct 3, 2009 at 14:27
  • This does not provide an answer to the question. To critique or request clarification from an author, leave a comment below their post. Feb 12, 2015 at 17:24

8 Answers 8


I used this page: http://www.simpledns.com/private-ipv6.aspx. it explained what the others are saying about it not really being required, but helped me "make something up".

I needed to supply a static IPv6 address to my IPv6-enabled DHCP server in Windows Server 2008 R2.

  • +1 I had exactly the same question. The above link is exactly what's needed.
    – Tim Long
    May 9, 2012 at 17:12

Since IPv6 will become the main growth protocol on the Internet around 2011, it is a good idea to keep IPv6 enabled and to learn how to do these things right.

The address that you mentioned, 192.168.x.x is an RFC1918 private address in IPv4. It is intended for traffic which is private to one network (or organization) and does not normally cross the organization's network boundaries. RFC 1918 cause people a lot of grief when companies are aquired because people often discover that two or more networks are using the same addresses. In some large companies, they have run out of RFC 1918 address space and have had to supplement it with registered addresses.

In IPv6, the equivalent type of address is called ULA. However, the block set aside for this usage is almost inconcievably vast. There is no way that anyone could ever use it up, and to avoid the possibility of collisions as much as possible, the IETF has asked people to pick their ULA block randomly. The easiest way to do this is to use the generator tool at SixXS. Type in a MAC address from your network card, click generate, and you have a ULA block. You can then use this block to assign IPv6 static addresses and subnets to all devices at your site. You can use any MAC address, it is just there to seed the random number generator.

If you want to, you can also register your use of that ULA prefix at the SixXS page, but you don't have to do this.

Note that the /48 gives you 16 bits of space to break out /64 subnets, so if you are just setting up one server on one network, then pick one /64 subnet and use one address. People often reserve low addresses for various things such as ::1 for a router.

Assuming that you choose the ULA fdec:c0bb:c329::/48, then you could pick fdec:c0bb:c329:0001::7 for your lucky new mail server on fdec:c0bb:c329:0001::/64

  • 3
    As a note from the future (2013): That IPv6 thing still isn't gaining a lot of traction ;) Oct 13, 2013 at 21:36
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    Really? I've noticed that some of our production Linux servers are actually using IPv6 to communicate internally even though nobody explicitly made that decision and told them to do it. It happened as a side effect of the default install turning on IPv6 and certain domain names being automatically populated with IPv6 addresses in /etc/hosts. IPv6 is pretty ubiquitious, it works and it is only at the Internet scale that there are issues with turning it on. Oct 14, 2013 at 0:53
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    You're right, it's like another network manifesting itself underneath the existing one... Primed to take over soon... (getting suspicious of IPv6 now :p) Oct 14, 2013 at 9:11
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    As a note from the future (2016): That IPv6 thing still isn't gaining a lot of traction ;) ;)
    – techie007
    Nov 8, 2016 at 13:57
  • As a note from the future (2022): That IPv6 thing still isn't gaining a lot of traction :(
    – T.J.L.
    Sep 7, 2022 at 0:21

The replacement for private IP addresses in IPv6 is the Unique Local Address.


It's only a warning. You can ignore it. It won't affect the promotion or operation of the DC if you're not using IPv6 addresses.


You shouldn't configure a static. IPv6 should come up with just the link-local address automatically.

  • link-local isn't routable so it might not be what he needs
    – Marcin
    Sep 25, 2009 at 13:18
  • Didn't sound like having routable IPv6 was required, since the reasons for not disabling it only seem to be due to it being an Exchange requirement (rather than a "real" requirement). Perhaps we could use some clarification on that point to know for sure? Sep 25, 2009 at 14:49
  • @Brian you are right, I'm not disabling ipv6 only to install Exchange correctly. Sep 25, 2009 at 15:39
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    Auto-configured IPv6 addresses for network elements and servers is not very sensible.
    – Steve-o
    Aug 28, 2011 at 5:37

If you disable IPv6 on an Exchange Server, your server will run, but it will throw multiple errors and it will take 3 times longer to fully reboot the system. I thought I have a major hardware failure when my server almost refused to fully reboot, umtil I found it was caused by disabling IPv6.


To clarify, if your Windows server has a 6to4 adapter (Device Manager>Network Adapters) it will generate and bind an IPv6 Address. Unchecking the protocol in the Ethernet properties box will not change that. If there is an IPv6 address, it will be included in the email header from your exchange server. Today, organizations such as GMAIL do reverse lookups on an IPV6 address if it is included, and will reject the message if there is not a reverse DNS entry for your IPv6 address. Many organizations have static IPv4 addresses with mx records and reverse DNS lookup but do not have or maybe don't know the static IPv6 addresses from their internet provider. In order to get mail to be accepted by gmail, they just disable the 6to4 Adapter. That works but is not a permanent fix, If IPv6 is not disabled in the registry, on restart, the server can create a new 6to4 Adapter to replace the disabled one. Not sure if the best approach is to disable IPv6, to contact your provider to see if they can provide static IPv6 addresses for you, or to create a reverse DNS entry for the ULA address your computer generated on it's own


I just made the following LAN-local v6 subnet and reverse DNS zone generator for my own use; I hope it may be generally helpful. It also handles multiple sizes of subnets:


  • 1
    That URL does not resolve anymore. Aug 29, 2019 at 18:07

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