I added a new domain tree to an existing AD forest which previously contained one domain. Let's call the new domain xyz.com and the existing forest root domain abc.com (the forest is abc.com).
Everything is in the same site.
Each domain has three DCs. The existing domain and forest is at Windows 2008 functionality and the new domain is at 2012 R2.
Replication is only occurring one-way. The new domain xyz.com receives inbound replication from the existing abc.com domain just fine, and it replicates internally just fine. Everything is good there.
The existing domain will not replicate from the new domain. This is because the Configuration partition in the existing domain has no information on the DCs in the new domain. Specifically, in the replica of the Configuration partition on the existing servers, CN=Servers,CN=MySite,CN=Sites,CN=Configuration,DC=abc,DC=com contains no entries for the new DCs in the new domain. However, the replica of the Configuration partition on the new DCs in the new domain has entries for all DCs in the forest.
The same is true of the other AD partitions, including the ForestDNS partition. Because the DNS is complete in the new domain, I pointed the DNS clients on the DCs in the existing domain to use DNS on the DCs in the new domain. That seems to have gotten me past all DNS created problems.
The two way trust between the domains seems to be working fine. The domains trust each other and users in both domains can login and access resources and be assigned security in either domain.
There are no replication errors... it is simply that the DCs in the existing domain will not replicate from the DCs in the new domain because they are not in the Configuration partition on the existing DCs. They don't "know" about the new DCs.
In other words: If I go in to AD Sites and Services on the existing DC's, the DCs in the new domain are not listed at all. Only the DCs in the original existing domain are shown. So the KCC does not create replication connections for the new DCs in xyz.com to the existing DCs in abc.com.
But on the DCs in the new domain, all servers are listed in Sites and Services and KCC creates the connections and everything replicates fine from abc.com to xyz.com.
Any suggestions on how to fix this? This is like a chicken and the egg.... AD won't replicate because it did not initially replicate.
Starting over is not a good option as both domains are in production use.
Thanks in advance!