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DNS issues Cannot resolve to domain controller from site B to site A


I have two site locations A and B.  I have an AD domain in site A.  I am trying to extend the domain from site A to site B.  The two sites are connected via VPN site to site connection using NAT over VPN as both sites unfortunately are using the same subnet.  (10.0.0.x).  So Site A is 10.0.0.x with NAT as 172.17.0.x.  Site B is also 10.0.0.x with NAT as 172.16.0.x.  I set the DNS on site B to point to site A using the NAT address.  The site A Domain is address which id NAT as  I added the as a primary DNS entry on site B systems and I am able to resolve site A DNS hostnames by running nslookup on a site B machine.  Problem is that I cannot join a machine from site B to the site A domain.  I have added Host A records to the site A DNS that point the domain with the NAT IP.  It does not seem to help.  Any help would be greatly appreciated!
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1 Solution
Microsoft does not support using Active Directory over NAT.  Please see:


Even unsupported, I don't think you can solve this problem with NAT'ing,  Issues come into play with clients needing to do lookups of the several automatically provisioned records in an active directory DNS structure, which will not be available in a situation like you've presented here.  There are several problems that you'll run into along the way.

My suggestion would be to change the addressing at one site.  I know this is a daunting/almost impossible task in some environments, but it's a necessity if you're trying to use active directory between the two networks.
biz1itAuthor Commented:
Yes unfortunately I had to bite the bullet and change the IP's on one site.  It's been a fun week....It is now working OK except for ironing out some issues with SQL jobs failing.

Thanks for your response!
Sounds like a fun week.  Keep plugging away, I'm sure there will be a few things to iron out after having to change the addresses, but it will be well worth it in the end.
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