I responded to this elsewhere.
> I just checked the first VoIP server I ever deployed with a non-standard SIP port. It's been up for a decade and provides public facing services so its accessible to the global internet minus whatever systems have found their way in to our denylist over the years.
And that is what is called “UDP”. Also the “spray and pray” of the networking world. Meaning, you literally don’t get a response.
Fundamental difference.
> The thing about non-standard ports is that unless your service identifies itself with a banner or similar upon connection the attacker has to open with a valid request to receive a response.
Which is exactly what ssh does and the point of why comparing the two and obscuring the port/IP makes no difference.