JRiver's Interact forum has a board on Remotes and one on Media Network.

In most cases, when you are asked for the Access Key, you can instead enter an IP address. If you prefer, you can use an IP address to connect. Please see the topic called 'Network Access' for more information. To achieve access from outside your network, your router must forward requests to the correct PC, and your firewall must allow access on the port being used (normally 52199). The Access Key method will work even if your outside address changes from time to time. One is for your server, as seen from inside your network (local), and the other is your outside address (Internet). This key is automatically generated by JRiver's servers. This might be JRemote, Gizmo, Panel, or Media Center itself. You then enter it on your client program.

You will find it on your server in Tools > Options > Media Network after Media Network is turned on. This is a six character string that is associated with the server (MC). Many of JRiver's Media Network features require use of an Access Key.

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