add AIRPLAY.md

AIRPLAY.md

@@ -0,0 +1,33 @@
+On macOS AirPlay should work out of the box.
+
+On Windows you need to have Bonjour service installed and running, dependency check widget can do that for you within the app.
+
+But on Linux you may need to open some ports in your firewall for it to work properly.
+
+Special thanks to [@medaminezghal](https://github.com/medaminezghal) for figuring this out and sharing the information with us.
+
+AirPlay requires these ports to be open on Linux
+
+```shell
+sudo firewall-cmd --add-port=7000/tcp --permanent
+sudo firewall-cmd --add-port=7001/tcp --permanent
+sudo firewall-cmd --add-port=7100/tcp --permanent
+sudo firewall-cmd --add-port=6000/udp --permanent
+sudo firewall-cmd --add-port=6001/udp --permanent
+sudo firewall-cmd --add-port=7011/udp --permanent
+sudo firewall-cmd --reload
+```
+
+If you want to use ufw instead of firewalld, you can run these commands:
+
+```shell
+sudo ufw allow 7000/tcp
+sudo ufw allow 7001/tcp
+sudo ufw allow 7100/tcp
+sudo ufw allow 6000/udp
+sudo ufw allow 6001/udp
+sudo ufw allow 7011/udp
+sudo ufw reload
+```
+
+I don't suggest disabling the `Use legacy ports` option in settings, if you have it disabled then ports might be different

src/settingswidget.cpp

@@ -235,7 +235,7 @@ void SettingsWidget::setupUI()
 #ifdef __linux__
     m_useLegacyPortsCheckbox = new QCheckBox("Use legacy ports");
     m_useLegacyPortsCheckbox->setToolTip(
-        "Use legacy AirPlay port behavior for compatibility.");
+        "Use legacy ports, refer to AIRPLAY.md for more information.");
     airplayLayout->addWidget(m_useLegacyPortsCheckbox);
 
     m_showV4L2CheckBox = new QCheckBox("Show V4L2 Button on AirPlay Widget");