Can audio delivery from VoIP providers be affected if the port range is not open in the firewall?

Audio delivery from VoIP providers can indeed be affected if the port range is not open in the firewall. VoIP communication relies on various ports for transmitting audio packets, and if these ports are blocked or filtered by a firewall, it can lead to issues such as one-way audio, call drops, or an inability to establish calls altogether.

When VoIP systems, like those using SIP (Session Initiation Protocol), are used, specific ports are required for signaling and media streams. If the firewall is not properly configured to allow traffic through these ports, the audio packets may be unable to reach their intended destination, leading to degraded call quality or failure to connect. This is particularly critical during call setup and for the transmission of ongoing audio, emphasizing the importance of ensuring the correct port ranges are open.

In contrast, if the port range were open, VoIP audio data could flow freely between devices, ensuring clear communication and reliable connectivity.