What is required for an app to receive incoming connections automatically?

For an app to receive incoming connections automatically, it must be signed by a valid certificate. When an application is properly signed, it indicates that the app has been verified and is from a trusted source. This signing process is essential because macOS employs Gatekeeper, a security feature that ensures only trusted software can be installed and run on the system. Applications with a valid signature can be configured to receive incoming connections without requiring user intervention.

This automatic allowance of connections helps streamline user experience, particularly for apps that need to establish network communications, such as servers or real-time collaboration tools. By ensuring that the app is signed, the operating system helps protect against malicious software that might attempt to create unauthorized connections. Consequently, applications that are not signed or are unsigned would not be automatically permitted to receive incoming connections, limiting their operational capabilities and increasing potential security risks.