SS, netstat, and tcpdump, to name a few programs, will all convert a port number to a name when recognized. So a connection on port 22 will instead be shown as 'ssh', as an example.
I'm wondering how this mapping is done? I assume that the programs aren't each hardcoding a list of mappings? Is there a central program or service responsible for helping networks map port number to name?
Related question, when I run SS on the same version of linux (6.9, so a bit old) I'm getting different behaviors. On the VM I was testing on the command 'ss -a' lists a program on port 11001; On a bare metal machine with the same OS & command the port is instead listed as metasys. It's easy enough to fix my script to get around the problem, but I'm curious why one serve recognizes port 11001 and the other doesn't.