Would be nice if the author had noted which are reserved vs which aren't, they're mixed in his list. Reserved might be a "formality" but it can be it's good to

Would be nice if the author had noted which are reserved vs which aren't, they're mixed in his list. Reserved might be a "formality" but it can be it's good to know which are informal vs. reserved since in some use cases you might want to follow the IANA, and it's generally a good idea to be aware of what rules you're breaking. There's a list here for reference: https://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers https://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbe...