[upd]: Portqry Udp

UDP port 33456: NOT LISTENING (ICMP Port Unreachable) Want to see if something on your own machine is bound to UDP but not responding?

Here’s an interesting angle on that often surprises people: Why portqry over UDP is tricky Unlike TCP, UDP is connectionless — no handshake, no ACK. So portqry can’t just “connect” to a UDP port to see if it’s listening. portqry udp

UDP port 53 (domain service): LISTENING Because Google DNS replies to a proper DNS query. But if you send to a random high UDP port with no service: UDP port 33456: NOT LISTENING (ICMP Port Unreachable)