You open the TCP/IP forwarding agent configuration dialog from a workflow configuration: you can right-click the agent icon and select Configuration..., or double-click the agent icon.

To open the TCP/IP collection agent configuration, click Build → New Configuration. Select Workflow from the Configurations dialog. When prompted to Select workflow type, select Realtime. Click Add agent and select the Processing tab in the Agent Selection dialog. Select the Tcp Ip agent. Double-click the agent icon or right-click the icon and select Edit agent, to display the Agent Configuration dialog.

General Tab

TCP/IP forwarding agent configuration dialog - General tab

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