SSH is made up of the client and server side. Before using the SSH service, first verify that you have SSH installed on your Linux system (each release has its own package management tools available), and use the following command to see if the server side (the one you want to log in remotely) has started:
# > NETSTAT-TL
Active Internet connections (only servers)
Proto recv-q send-q Local address Foreign address state
TCP 0 0 *:ssh *:* LISTEN
Netstat is a network query command whose parameter "-T" shows the connection behavior of the TCP packet, and the parameter "-L" is the display listening state. If the "NETSTAT-TL" output is as shown in the preceding code, the server-side SSH service is started.
If the SSH service does not start, you need to start it manually: in the/ETC/INIT.D directory, look for "ssh" or "sshd" files, if found, execute the following command:
Some Linux distributions "INIT.D" directories are not necessarily under "/etc", depending on the specific version.
If you want to start the SSH service automatically, under Gentoo can:
# rc-update Add/etc/init.d/ssh Default
Other Linux distributions also have their own set-up methods, which, if not clear, may be based on the specific release version of Google.
See if SSH is started