We need to setup a one-way AD trust to a domain in another company via a private connection.
In our DNS, we create a conditional forwarder by specifying the domain of the other company and also an IP address of their domain controller.
We are still not be able to resolve their domain name when we ping. The server FDQN is still not be resolved in this conditional forwarder's properties.
The required firewall ports being specified in this link https://support.microsoft.com/en-us/kb/179442#method3
are already opened
Please advise what we should check.