System prefers auto-generated IPv6 address over configured one

[Terry Kennedy]

I have a number of systems with various flavors of Windows 7 installed - x64, x86, Home Premium, Ultimate, and so on. Some were factory installs, some were installed by me at various times.

Although I manually configured an IPv6 address on each system, they all exhibit the problem of using an automatically-generated IPv6 address instead of the one I have configured. This makes it difficult to connect to servers which use IP addresses for access control, as the automatically-generated addresses change on reboot.

Here's the output of ipconfig/all:

Windows IP Configuration
   Host Name . . . . . . . . . . . . : office
   Primary Dns Suffix  . . . . . . . :
   Node Type . . . . . . . . . . . . : Hybrid
   IP Routing Enabled. . . . . . . . : No
   WINS Proxy Enabled. . . . . . . . : No
   DNS Suffix Search List. . . . . . : tmk.com
Ethernet adapter Bluetooth Network Connection:
   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Bluetooth Device (Personal Area Network)
   Physical Address. . . . . . . . . : 00-1B-DC-0F-6C-D0
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
Ethernet adapter Local Area Connection:
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Intel(R) 82567LM-3 Gigabit Network Connection
   Physical Address. . . . . . . . . : 00-22-19-1D-FE-43
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   IPv6 Address. . . . . . . . . . . : 2430:1432:1:2::51(Preferred)
   IPv6 Address. . . . . . . . . . . : 2430:1432:1:2:7cbd:6207:7849:c5ba(Preferred)
   Temporary IPv6 Address. . . . . . : 2430:1432:1:2:60ee:fe68:8697:cf8a(Preferred)
   Link-local IPv6 Address . . . . . : fe80::7cbd:6207:7849:c5ba%10(Preferred)
   IPv4 Address. . . . . . . . . . . : 10.4.35.51(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . : 2430:1432:1:2::1
                                       fe80::219:e8ff:fee8:56ff%10
                                       10.4.35.1
   DNS Servers . . . . . . . . . . . : 10.4.35.61
                                       10.4.40.135
   NetBIOS over Tcpip. . . . . . . . : Enabled
Tunnel adapter isatap.{F4779738-7244-4B7D-B0B4-62247E5B16CC}:
   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Microsoft ISATAP Adapter
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
Tunnel adapter Local Area Connection* 9:
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   IPv6 Address. . . . . . . . . . . : 2001:0:4137:9e76:3cd1:d37:3372:dccc(Preferred)
   Link-local IPv6 Address . . . . . : fe80::3cd1:d37:3372:dccc%13(Preferred)
   Default Gateway . . . . . . . . . :
   NetBIOS over Tcpip. . . . . . . . : Disabled
Tunnel adapter isatap.{069EB6C1-BDF6-402F-8F22-A2F780C0FC2B}:
   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Microsoft ISATAP Adapter #2
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes

Note that the system lists 3 IPv6 addresses, one which I have hard-coded, an auto-generated one marked "preferred" and another auto-generated one which is not marked "preferred". When I try to access another IPv6 host on the same LAN, the connection comes from the 2430:1432:1:2:60ee:fe68:8697:cf8a address.

I've searched for a way to force Windows to use the IPv6 address I configured and I haven't found anything that worked.

 

[kegobeer]

This is probably due in part to the huge block of ULAs available for IPv6. Have you seen this?

windows server 2008 - "ipv6 equivalent" of 192.168.x.x (configuring a static ipv6 address) - Server Fault

And have you reviewed RFC 2373, which explains IPv6?

RFC 2373 - IP Version 6 Addressing Architecture (RFC2373)

What are you using that's requiring IPv6?

 

[Terry Kennedy]

This is probably due in part to the huge block of ULAs available for IPv6. Have you seen this?

I'm not sure I follow you. I have a real IPv6 allocation from my ISP, not a ULA. I manually configured an IPv6 address from that allocation on each client PC. Windows is taking the prefix I was assigned and creating 2 additional addresses within that allocation for some reason.

 

[kegobeer]

It wasn't clear to me that you were assigned an IPv6 address. I thought you were trying to create your own.

According to this article, Microsoft doesn't quite conform to the RFC. You might have to disable the auto configuration.

I don't know if you've read this, but here it is: Windows 7 and IPv6: Useful at Last? « IT Expert Voice

 

[Terry Kennedy]

According to this article, Microsoft doesn't quite conform to the RFC. You might have to disable the auto configuration.

I don't know if you've read this, but here it is: Windows 7 and IPv6: Useful at Last? « IT Expert Voice

I tried the command mentioned there, "netsh interface ipv6 set global randomizeidentifiers=disabled" and rebooted, and I still get the random IP addresses. This seems seriously broken to me - if I configure an IPv6 address, I expect Windows to use it.

 

[Terry Kennedy]

I tried the command mentioned there, "netsh interface ipv6 set global randomizeidentifiers=disabled" and rebooted, and I still get the random IP addresses. This seems seriously broken to me - if I configure an IPv6 address, I expect Windows to use it.

I found it. The command "netsh interface ipv6 set privacy state=disabled" is also required. Rebooting was necessary (in my case - it might not be if no IPv6 connections are open when the command is given).

This behavior does seem really bizarre to me, though - if a client PC randomly picks an address to source IPv6 connections from and it changes on every reboot, how can administrators track down which system used a particular random address at some point in the past?