Introducing IPv6 - impact on DNS?

Question

I am starting to add IPv6 addressing to my network, only a couple of Win2008x servers have both IPv4 and IPv6 enabled. The DNS servers at branch offices are still running Win2003.

I am at a branch office with a Windows 7 laptop running both IP v6 and v4. This branch office has a Windows 2003 DHCP and DNS server. The WAN link from this branch back to head office is IPv4 only.

If I try and ping any head-office host it fails unless I use the -4 flag, ie:

C:\Users\chrisg>ping web1 Ping request could not find host web1. Please check the name and try again.

C:\Users\chrisg>ping -4 web1

Pinging web1.ip.hbl [10.200.1.20] with 32 bytes of data: Reply from 10.200.1.20: bytes=32 time=2ms TTL=125 Reply from 10.200.1.20: bytes=32 time=6ms TTL=125

I suspect this problem is related to NRPT (I have a DirectAccess server setup). Perhaps this Windows 7 client has gotten into a confused NRPT state and thinks it needs to use IPv6 when it is not connected to the head office LAN ?

Answer 1

I think you are correct that this is related to NRPT but I think that the root cause is that NRPT knows you are inside the enterprise and it is (correctly as far as it is concerned) opting to use IPV6 even though its not available in this location. My understanding of the Corporate Connectivity Detection mechanism is that it should figure this out - it is supposed to run through a number of tests to ensure that it actually has full IPv6 connectivity back to the "core" corporate network, but clearly something has come unstuck. The scenario that you are having issues with relies on ISATAP and possibly the issue is with that aspect of DirectAccess.

There is some information on this in this technet article where they describe the steps that are needed to enable branch office scenarios.