Informational

The openssh-server package should already be installed, to verify this you can use the following command:

# apt list openssh-server
You should see the version with [installed] after it like this:


If it’s not installed, you can use this command to install it:

# apt install openssh-server
When enabling the service, be sure to fully secure SSH first.  I will cover some of the basics briefly, but this is not meant to be a guide on securely running an SSH server.  Since Kali comes with pre-generated SSH keys, to make it more secure, the first thing we will do is generate new ones.

To backup the original keys first as a precaution use:

# mkdir /etc/ssh/default_keys
# mv /etc/ssh/ssh_host_* /etc/ssh/default_keys/
Then to regenerate the keys:

# dpkg-reconfigure openssh-server
The next step is to edit the SSH server configuration file with the settings you need:

# nano /etc/ssh/sshd_config
If you are only planning on using SSH briefly the defaults are probably fine.  If you think you will use it for a length of time I would recommend at minimum enabling public key authentication:

PubkeyAuthentication yes
Then disabling password authentication:

PasswordAuthentication no
You could also allow the root user login here, but instead consider creating a non-privileged user account instead.

It’s useful to know that Systemd has different units, a unit configuration file encodes information.  The units relevant to SSH are ssh.service and ssh.socket. At a basic level a service unit controls a process and a socket unit controls a filesystem or network socket.

If you only need to temporarily start up the SSH service it’s recommended to use ssh.socket:

# systemctl start ssh.socket
When finished:

# systemctl stop ssh.socket
To instead permanently enable the SSH service to start whenever the system is booted use:

# systemctl enable ssh.service
Then to use SSH immediately without having to reboot use:

# systemctl start ssh.service
To check the status of the service you can use:

# systemctl status ssh.service
To stop the SSH service use:

# systemctl stop ssh.service
And to disable the SSH service so it no longer starts at boot:

# systemctl disable ssh.service