Why can't nmap see port 22?

Question

linux

Actually a question
Why nmap does not see the 22nd port?

Answer 1

I see:

$ nmap -p22 127.0.0.1

Starting Nmap 7.01 ( https://nmap.org ) at 2016-09-20 13:09 MSK
Nmap scan report for localhost (127.0.0.1)
Host is up (0.00022s latency).
PORT   STATE SERVICE
22/tcp open  ssh

Nmap done: 1 IP address (1 host up) scanned in 0.10 seconds

Could you write more details...