In cases where a call to the virtual number is made from a phone number not recognized as part of the ongoing number masking session there are three options to handle this situation:
- PIN-based authentication (recommended): Plivo ensures secure communication by requiring a PIN to enter the session. The caller receives a unique PIN and must enter it to connect. This maintains session integrity. Enable PIN-based authentication by setting is_pin_authentication to true during the session creation. (default is false).
- Unknown caller prompt (optional): If PIN authentication is disabled, use the unknown_caller_play parameter (optional) to play a message instructing the caller to use their registered number. This parameter only accepts .mp3 or .wav files.
- Call failure (default): If neither PIN authentication nor the unknown caller prompt is enabled, the call will fail.
Please review our quickstart guide and API reference to understand how PIN authentication works.