I'm trying to use Network framework for a UDP connection. It works, I get traffic flowing both ways when UDP server is responding, however when the server is down and box sends ICMP port unreachable completion blocks from nw_connection_receive_message() nw_connection_receive() are not getting called. State and viability change handlers are also not getting called. In my app console though I see message [connection] nw_socket_get_input_frames [C1:1] recvmsg(fd 4, 9216 bytes) [61: Connection refused] So somewhere inside of the API it actually gets the ICMP and knows that connection is refused, but how exactly do I get notified about this? This surely beats waiting on connection and timing out if host is nice enough to tell you that port is closed right away.

I have a system extension, it's not meant to be activated by user, i.e. this should be done by MDM. I'd like to verify if the extension is already active, but don't want to cause system popup because this is an error condition, i.e. something went wrong with MDM and we really don't want to confuse users with weird system popups coming out of nowhere. In short - not active, fine, give me an error, but please don't pop. Is there way to do this? Kind of what systemextensionsctl list command does.