You need to run a script called /etc/init.d/ssh to stop, start, and restart the OpenSSH server. You can also use the service command to control a System V init script. If you are using the latest version of Ubuntu such as 12.04 LTS or 13.04+, you need to use upstart job based commands as listed below.
Start / Stop / Restart / Reload OpenSSH Server on Ubuntu
Latest version of Ubuntu such as Ubuntu Linux 16.04 LTS or 18.04 LTS and others use the systemctl command to control ssh server on Ubuntu. Older version use the service command. To find out your Ubuntu Linux version, type:
lsb_release -a
cat /etc/*release*
Sample outputs:
No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 17.10 Release: 17.10 Codename: artful
Ubuntu Linux: Start OpenSSH Server
Type the following command:
$ sudo /etc/init.d/ssh start
OR
$ sudo service ssh start
OR for systemd based Ubuntu Linux 16.04 LTS or above server:
$ sudo systemctl start ssh
Ubuntu Linux: Stop OpenSSH server
Type the following command:
$ sudo /etc/init.d/ssh stop
OR
$ sudo service ssh stop
OR for systemd based Ubuntu Linux 16.04 LTS or above server:
$ sudo systemctl stop ssh
Ubuntu Linux: Restart OpenSSH server
Type the following command:
$ sudo /etc/init.d/ssh restart
OR
$ sudo service ssh restart
OR for systemd based Ubuntu Linux 16.04 LTS or above server:
$ sudo systemctl restart ssh 
Ubuntu Linux: See status of OpenSSH server
Type the following command:
$ sudo /etc/init.d/ssh status
OR
$ sudo service ssh status
OR for systemd based Ubuntu Linux 16.04 LTS or above server:
$ sudo systemctl status ssh
Sample outputs:
? ssh.service - OpenBSD Secure Shell server
Loaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enabled)
Active: active (running) since Wed 2017-08-30 01:25:08 UTC; 1h 14min ago
Process: 987 ExecReload=/bin/kill -HUP $MAINPID (code=exited, status=0/SUCCESS)
Main PID: 672 (sshd)
Tasks: 13 (limit: 4915)
CGroup: /system.slice/ssh.service
??672 /usr/sbin/sshd -D
??785 sshd: veryv [priv]
??791 sshd: veryv@pts/0
??792 -bash
??797 sudo -i
??798 -bash
??950 sshd: vivek [priv]
??956 sshd: vivek@pts/1
??957 -bash
??968 sudo -i
??969 -bash
??992 systemctl status ssh
??993 systemctl status ssh
Aug 30 02:31:30 gce-usa-debian-9-backup-1 sshd[950]: pam_unix(sshd:session): session opened for user vivek by (uid=0)
Aug 30 02:31:41 gce-usa-debian-9-backup-1 sudo[962]: vivek : TTY=pts/1 ; PWD=/home/vivek ; USER=root ; COMMAND=/bin/bash
Aug 30 02:31:41 gce-usa-debian-9-backup-1 sudo[962]: pam_unix(sudo:session): session opened for user root by vivek(uid=0)
Aug 30 02:32:56 gce-usa-debian-9-backup-1 sudo[968]: vivek : TTY=pts/1 ; PWD=/home/vivek ; USER=root ; COMMAND=/bin/bash
Aug 30 02:32:56 gce-usa-debian-9-backup-1 sudo[968]: pam_unix(sudo:session): session opened for user root by vivek(uid=0)
Aug 30 02:37:25 gce-usa-debian-9-backup-1 systemd[1]: Reloading OpenBSD Secure Shell server.
Aug 30 02:37:25 gce-usa-debian-9-backup-1 sshd[672]: Received SIGHUP; restarting.
Aug 30 02:37:25 gce-usa-debian-9-backup-1 systemd[1]: Reloaded OpenBSD Secure Shell server.
Aug 30 02:37:25 gce-usa-debian-9-backup-1 sshd[672]: Server listening on 0.0.0.0 port 22.
Aug 30 02:37:25 gce-usa-debian-9-backup-1 sshd[672]: Server listening on :: port 22.Controlling sshd using upstart based commands (this syntax is no longer works with the latest version of Ubuntu)
Since the script /etc/init.d/ssh has been converted to an Upstart based job, try the following commands to start / stop / restart the OpenSSH server:
Stop/Start/Restart the OpenSSH using the following commands
The syntax is:
sudo stop ssh sudo start ssh sudo restart ssh sudo status ssh |
Sample outputs:
7 comment
Really? Starting, stopping, and restarting all require the exact same instructions?
Thanks for the heads up, it was a typo. The FAQ has been updated.
Maybe this should be updated with the new ‘service $foo (start|stop|restart)’ offering?
Isnt it suprising that all the restarts have the same syntax. But yes they do.
Stop/Start/Restart the OpenSSH using the following commands
The syntax is:
sudo stop ssh
sudo start ssh
sudo restart ssh
sudo status ssh
Good info…
Thanks
If you are one of those hardcore Linux guys, and have installed openssh from source, the only way I found to start the server was..
root:~# /usr/local/sbin/sshd -d
(or)
root:~# /usr/sbin/sshd -d