Some features of X-Plane require that X-Plane be able to communicate across your network. These features include:
- networked multiplayer flights,
 - multi-computer simulations,
 - integration with apps on your phone or tablet.
 
In order for your computer to “see” the other computers in the situations above, you must first allow X-Plane to communicate through your firewall. If your computer is not running a firewall, of course, this is of no concern to you.
Windows
In Windows 10, if Windows Defender Firewall comes up automatically, you can allow X-Plane through the firewall in that popup. Otherwise, to allow X-Plane through the firewall manually,
- Open Windows Security.
 - Click on Firewall & network protection.
 - Click the Allow an app through firewall option.
 - Click the Change settings button.
 - Check the X-Plane app. If the app isn’t on the list, click the Allow another app button to locate it.
 - Check which type of networks the app can use to access the network.
 - Click the OK button.
 
In Windows Vista and Windows 7,
- Open Windows Firewall by clicking the Start button, clicking Control Panel, clicking Security, and then clicking Windows Firewall.
 - In the left pane, click Allow a program through Windows Firewall. If you are prompted for confirmation, click Allow.
 - (Windows 7 only:) Click Change settings, then click Allow if asked for confirmation.
 - Select the check box next to X-Plane, and then click OK.
 
To allow a program through the firewall in Windows XP, follow Microsoft’s instructions in Knowledge Base Article 842242.
MacOS
To allow X-Plane through the firewall in Mac OS,
- Open System Preferences from the Apple menu.
 - Click Security & Privacy.
 - Click the Firewall tab.
 - Unlock the pane by clicking the lock in the lower-left corner and enter the administrator username and password.
 - Click Firewall Options… to customize the firewall configuration.
 - Click the + (plus) button, then navigate to your copy of X-Plane.app. With X-Plane selected, click Add.