I would like to know if there is any specific port that License Manager uses to communicate with AD, other than the default 5048 port?

We have the following setup and running into communications issues:

We have 3 LF environments, PROD, QA and DEV. The DEV environment is closed off from the normal PROD network to avoid accidental communication to any of the other PROD systems running.

Our License Manager is installed on our PROD LF Server and communicates successfully with the LF Server in Dev and is able to communicate and inform the DEV server of licenses allocated to it. This was done when we had opened the relevant port to that server etc.

We are now trying to switch over to a Windows Accounts based architecture and need to test this in our DEV environment. The challenge is that the DEV environment contains its own AD that only broadcasts in that secluded environment. So by default when addig a new Named User on License Manager, it is the one from the PROD AD and when the user is allocated on the DEV LF Server, it does not pick up that it has a Named Licenses. in QA and PROD it registers the User correctly.

I then tried to add a location on License Manager to include the AD from the DEV environment, but get back a "Access Denied" error. The account being used does have sufficient rights on the DEV AD so it cannot be that. I also used telnet to establish that port 5048 is open between the Server hosting the LM instance and the DEV AD server.  

therefore my assumption is that it must be using a different Port for communication, or is there something else that I am missing?