vCenter Server generates IPv6 address starting with 2002

Scenario
While troubleshooting communication error & conflicts on one of the production vCenter Server, stumped into this issue. Even though the IPv6 is unchecked under IP/DNS properties windows, the server generates a IPv6 address that starts with 2002. You can see this address when you run ipconfig/all on the vCenter Server in question. Below is the output for your reference.
Tunnel adapter 6TO4 Adapter:
Connection-specific DNS Suffix  . :
Description . . . . . . . . . . . : Microsoft 6to4 Adapter
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
IPv6 Address. . . . . . . . . . . : 2002:ad0a:196::ad0a:196(Preferred)
Default Gateway . . . . . . . . . :
DNS Servers . . . . . . . . . . . : xxx.xx.x.x
xxx.xx.x.x
NetBIOS over Tcpip. . . . . . . . : Disabled
 
About the 6to4 tunneling protocol : By default, the 6to4 tunneling protocol is enabled in Windows 7, Windows Vista, Windows Server 2008 R2, and Windows Server 2008 when an interface is assigned a public IPv4 address (that is, an IPv4 address that is not in the ranges 10.0.0.0/8, 172.16.0.0/12, or 192.168.0.0/16). 6to4 automatically assigns an IPv6 address to the 6to4 tunneling interface for each such address that is assigned, and 6to4 will dynamically register these IPv6 addresses on the assigned DNS server. If this behavior is not desired, we recommend that you disable IPv6 tunnel interfaces on the affected hosts. Alternatively, the 6to4 network adapter driver will be visible in the device manager. Below is the screen capture for your reference:
vc1
 
 
 
 
  
Cause
This may sometimes create conflicts in network communication within vCenter Server components such as login failure using vSphere Client. If  are not using IPv6 in your environment it is recommended to turn it off. (Also, based on Microsoft recommendations) 
Resolution
Follow the steps involved in the below MS article to modify registry settings on the affected server. Automatically disable or re-enable IPv6 or its components- http://support.microsoft.com/kb/929852 . To disable certain IPv6 components, follow these steps:
> Click Start, type regedit in the Start Search box, and then click regedit.exe in the Programs list.
> In the User Account Control dialog box, click Continue.
> In Registry Editor, locate and then click the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters\
> Double-click DisabledComponents to change the DisabledComponents entry. 
Note If the DisabledComponents entry is unavailable, you must create it. To do this, follow these steps:
In the Edit menu, point to New, and then click DWORD (32-bit) Value.
vc2 vc3
 
 
 
 
 
 
> Type DisabledComponents, and then press Enter. Double-click DisabledComponents.
> Type 0x01 to disable IPv6 on all tunnel interfaces. These include Intra-Site Automatic Tunnel Addressing Protocol (ISATAP), 6to4, and Teredo. 
> Reboot the server post the registry change. Once the server is online, verify by running ipconfig/all and device manager to see if the 6to4 adapter and all ISATAP adapters are gone.
vc4
 
 
 
 
 
You should be all set now. 
—————————————————————————————————————————————————————-
Type any of the following values in the Value data field to configure the IPv6 protocol to the intended state, and then click OK:
Type 0 to re-enable all IPv6 components (Windows default setting).
Type 0xffffffff to disable all IPv6 components except the IPv6 loopback interface. This value also configures Windows to prefer using IPv4 over IPv6 by changing entries in the prefix policy table. For more information, seeSource and destination address selection.
Type 0x20 to prefer IPv4 over IPv6 by changing entries in the prefix policy table.
Type 0x10 to disable IPv6 on all nontunnel interfaces (both LAN and Point-to-Point Protocol [PPP] interfaces).
Type 0x11 to disable all IPv6 interfaces except for the IPv6 loopback interface.
 
If you wish to know more, visit this blog: IPv6 for the Windows Administrator: The 2002: (6to4 Tunnel) Address and its Impact from Microsoft TechNet which details what is 6to4 tunneling/IPv6 address and its impact on the Directory services – AD/DNS and name resolution.
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About cloudray

Predominantly based around Virtualization, but will include other technology related information and anything else I find interesting and feel the need to share with you. I also use this Blog as both a place to store useful information that I think that will come in handy to me at some point in the future, and also a place to help aid my learning. I find a great way to learn about something is to research about it and then write it up in my own words. I'm Pushpal Ray, from India. As a certified VCP3/4/5 professional, I am currently working as an Independent Consultant. Over 10 years of IT-industry experience, currently focused around the Desktop Virtualization(End-User Computing). I also have extensive experience in Windows Administration, Datacenter Migration, Workload profiling & benchmarking. At my leisure, I enjoy hiking, running, photography, spend hours in my fav coffee shop & spend quality time with my wife. Occasionally, catch up with few friends for a drink!
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