The port that does not exist
Ask any program to listen on port 0 and it will hand you a socket on port 47193...or 58037...or whatever the kernel felt like that day. Port 0 is not a port you can have. It is the number you pass when you want the operating system to pick one for you.
But a TCP header is just bytes. The destination port field is 16 bits wide, and 0x0000 fits in 16 bits as well as anything e
https://www.osnews.com/story/146330/the-port-that-does-not-exist/
