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In the GUI, select the File > Preferences menu item
Click the triangle next to General, then click Network Connections.
For Active Provider, select Manual.
Select HTTP (in Proxy entries list)
Click Edit.
Enter values for Host and Port.
Optional: Select Requires Authentication and enter values for User and Password.
Select HTTPS (in Proxy entries list).
Click Edit.
Enter values for Host and Port.
Optional: Select Requires Authentication enter values for User and Password.
Click OK.
Your proxy is now set up.