Throughout my work with domain migrations, there are inevitably some very basic steps before getting deep into User attributes, Groups, Computers, and the myriad of ways that client applications use Active Directory that need to be transitioned to a new directory. Before any of that happens, there is that moment when the networks can first communicate with each other, or at least the respective network teams say they networks can see each other and all the appropriate ports are open. This is the opening of the door to the greater transition, but if everything isn’t quite right, you could find yourself battling issues down the road. Using this simple script from the source to the target DCs and vice versa will allow you confidence that the network team has configured the connectivity correctly for Domain or Forest Trust connectivity as well as application port openings.
Test-NetConnection –ComputerName “DC1” -Port 389
Other ports to test for successful AD Trust Connectivity
Once you have the ports confirmed to be open, you can then get to the heavy lifting of object and attribute migrations to bring your AD migration forward.
More tips from along the migration path are ahead.