[hnfong]

This was on HN two(?) days ago: https://news.ycombinator.com/item?id=39313170

> I wrote the initial version of SSH (Secure Shell) in Spring 1995. It was a time when telnet and FTP were widely used.

> Anyway, I designed SSH to replace both telnet (port 23) and ftp (port 21). Port 22 was free. It was conveniently between the ports for telnet and ftp. I figured having that port number might be one of those small things that would give some aura of credibility. But how could I get that port number? I had never allocated one, but I knew somebody who had allocated a port.

Emphasis mine.

Cheers.

[ciceryadam]

https://docs.oracle.com/cd/E36784_01/html/E36870/ssh-1.html from man page: It is intended to replace rlogin and rsh, and to provide secure encrypted communications between two untrusted hosts over an insecure network.