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damien1234

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Child domain LDAP queries

I'll get to the question first.  My server, which is part of a child domain is sending LDAP requests to the primary root domain/forest controllers.  Why?  I don't want this to happen.

Here is the setup
2 total domains
Root domain/forest = abc.com
Child domain = xyz.abc.com
DC in child domain = AD1.xyz.abc.com
Another server in the child domain has ad1.xyz.abc.com as the ONLY DNS and WINS server. Of course that server is part of xyz.abc.com domain. The firewall blocks all AD communication (DNS, WINS, LDAP, RPC, Kerberos, SAM/LSA, Netbios, NTP, etc.) EXCEPT traffic between primary and child domain DC's.

Logins to child domain with primary domain accounts is slow (but successful), most likely since LDAP-UDP commumications from server are purposefully blocked.  Is it asking to much for my child DC to do ALL the authentication work?  Why are my other servers even trying to contact the root domain?  The reason I am doing this is for security but I don't know if it is a good or best practice.
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Avatar of Chris Dent
Chris Dent
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Avatar of damien1234
damien1234

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The DC in the child domain is a Global Catalog too.

Are they in the same site in AD?

Chris
So I created a new site and put the child DC in it.  I then logged on and saw a LDAP-389-UDP and a SAM/LSA-445-TCP packet dropped.  Login was successful but slow.
Well, I found a white-paper from Microsoft which was specifically about how to setup DC-DC communications through firewalls AND guarantee that the clients in each Site could only authenticate with the DC in their domain. It talked about setting up IPSEC but at the end of the day my method is exactly the same except my DC-DC traffic is not encrypted... and I don't need it to be encrypted.  My firewall guarantees that ONLY the DC's can talk to each other.  Anyway this has nothing to do with the behaviour of the other servers trying to contact DC's in the other site.  If Microsoft says I am doing everything right then maybe I'm just being anal.  After all authentication works.

Critical Points:
DC's need to be GC's
If Sites are used then replication and replication traffic is ALL that matters, nothing else.

It's beautiful, NONE of my other severs can browse an AD domain other than their own!  This is exactly what I wanted to have happen!  WooHoo!
See my final explanation.  It's critical that the DC is a GC.  It's not as critical for the child to be in a different AD site since that really is all about replication (at least in my scenario anyway)