In my Mac(192.168.2.228), it will send ICMP packet to my house's router (192.168.2.1).
with the info
Destination unreachable (Port unreachable)
and in the Wireshark packet detail panel, there displays the packet structure:
and more details:
the payload is
IP:UDP (from router to mac), and you see the router port is
53, it related to DNS.
and in my macOS, there is no application listening the port:
$ netstat -an | grep 55166 get nothing.
What's the protocol use the packet? and what's the intension of the packet?