There is only one file type that uses the .NETWORKCONNECT extension:
Apple Network Connect Document
Document created by Apple's System Preferences, an application included on the Apple operating system; contains information that helps you set up your network.
To set up a network connection, click the apple icon in the top-left of your screen, then choose, then click "Network." You can enter the network settings from here.
Another way to set up your network connection is to use the Network Setup Assistant to guide you through the process. When in the Network pane of System Preferences, click the "Assist me..." button near the bottom of the window. Follow the prompts to set up your network.
|Apple System Preferences|
Updated: September 6, 2015