(iOS 17.3) I'm using the Apple supplied iOS sample project "ConfiguringAWiFiAccessoryToJoinTheUsersNetwork" as a base to write an App to configure an existing WiFi device using the NEHotspotConfiguration API's. I have almost everything working, and can join the network and send a packet to the device to configure it. I know that it is working as the device responds properly to what I send it. But I am not able to receive the response back from the device to the packet sent. (Only need 1 packet sent and 1 packet received) However. If I run a packet sniffer on the phone before running my test App, then I do get a response. No packet sniffer running, no response. When I do a debugDescription on the NWConnection after it reaches ".ready", I notice that when the sniffer is running I'm using loopback lo0: [C1 connected 192.168.4.1:80 tcp, url: http://192.168.4.1:80, attribution: developer, path satisfied (Path is satisfied), viable, interface: lo0] and I get a packet response in the NWConnection receiveMessage callback. But with no sniffer running, I get interface en0: [C1 connected 192.168.4.1:80 tcp, url: http://192.168.4.1:80, attribution: developer, path satisfied (Path is satisfied), viable, interface: en0[802.11], ipv4, dns, uses wifi] and there is no callback to the receiveMessage handler and the NWconnection eventually times out. The interface used seems to be the only difference that I can see when I have a sniffer running. Any ideas as to why I can't see a response in "normal" operation?