Port 22 — SSH / SFTP

Security guidance

Open is normal, but use key-only authentication, disable root login, and consider fail2ban. Moving it to a non-standard port reduces log noise, not real risk.

Test port 22 yourself

From your own machine, against any host (swap in your domain):

macOS / Linux — netcat

nc -vz example.com 22

Any OS — nmap

nmap -p 22 example.com

Windows — PowerShell

Test-NetConnection example.com -Port 22

open = a service answered on port 22; closed = the host replied but nothing is listening; filtered = a firewall silently dropped the probe. These test from your network — our port checker tests from the outside, the view that matters for security.

Other common ports