If you have a configuration that receives IDocs or RFC Listener calls from SAP, you will have to run the NLINK Server and use the SAP GUI to look for the registration in SAP.

Step-by-step guide

Gateway Monitor

Make sure the appropriately configured NLINK meta-database is the Active Meta-Database.
Start the NLINK Server.

The NLINK Server must start successfully. You can only see the registration when the Server is running.
In SAP GUI, go to transaction SMGW.
From the menu, choose Goto >> Logged on clients.
Look for entries with the NLINK Server computer name as Host Name and with TP Name as the program id (the PROGRAM_ID parameter of the destination).

RFC Destination

In SAP GUI, go to transaction SM59.
Find the appropriate RFC Destination and double-click or choose Display.
From the toolbar, click Connection Test.
From the toolbar, click Unicode Test.
From the menu, choose Extras >> Function List. An IDoc connection should show (at least) the function module IDOC_INBOUND_ASYNCHRONOUS. An RFC Listener connection should show all the function module(s) configured in the running NLINK meta-database.

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