I am using putty and private key to access my development server. I used Nmap online port scanner, to see which ports are visible to the public, and in fact, the 22 is open.
My question is, is it possible to hide open port from the public?
If it is not, how secure is the SSH connection with a private key?
I did the following:
- I placed a private key on the USB key (it is not even on my personal computer.)
- made configuration you can not log in with "root" username to server.
- applied Limit option to port 22 with UFW. (I think potential intruders have only 6 attempts, then they go on timeout)
The 22 is the only port opened. My question is, how safe is this? Do hackers have any chance to get in?