I am currently developing two iOS applications that require peer-to-peer connectivity. To facilitate this, I've implemented NWListener and NWConnection in both apps for network communication. To determine each device's public IP address and port—necessary for establishing a connection over the internet through my mobile operator's Carrier-Grade NAT (CGNAT)—I'm using a STUN server. Despite successfully retrieving the external IP addresses and ports for both devices, I am unable to establish a peer-to-peer connection between them. My current setup involves initiating a connection using the public addresses and ports discovered through the STUN server response. However, all attempts to connect the devices directly have been unsuccessful. I am seeking guidance on whether there are additional considerations or specific configurations needed when using NWListener, NWConnection, and a STUN server to establish a direct connection between devices in a CGNAT environment. Is there a particular step or network configuration I might be missing to successfully connect both iOS devices to each other using their external network details?

Hello fellow developers and Apple support, I'm experiencing a challenging issue with NWConnection when sending data via QUIC udp datagrams to multiple devices. I have a setup where I use NWListener to send data every 10 milliseconds to 10 or even 15 clients, which works flawlessly. However, when I switch to using NWConnection to send data every 20 milliseconds, I encounter significant packet loss, and the following error messages appear in the console: nw_connection_create_with_connection_internal [C19] Original connection not yet connected nw_connection_group_create_connection_for_endpoint_and_parameters [G2] failed to create connection with parameters QUIC, traffic class: 300, local: 0.0.0.0:9000, attribution: developer, attach protocol listener This issue is mitigated when a second NWConnection is connected to the same NWListener, reducing the frequency of errors. By adding a third connection, the errors almost disappear, which suggests that the problem might be related to how a single NWConnection handles rapid data transmissions. This observation leads me to believe that the issue could be linked to the capacity or the management of connections under high throughput scenarios (200kb every 20ms). I've thoroughly reviewed the documentation for NWConnection and NWListener, focusing on their QUIC protocols handling, without finding a clear cause or solution for this issue. I've also searched through forums and developer communities for similar problems but haven't found anything that matches my situation closely. Thank you in advance for your time and help!