Install OpenSSH on Ubuntu 22.04 (Jammy Jellyfish) - Step by step guide ?

OpenSSH is a connectivity tool that allows secure communication between client and server. The traffic is encrypted to discourage eavesdropping, connection hijacking, MITM attack, and other attacks.

Here at LinuxAPT, we shall look into how to install OpenSSH server on an ubuntu machine. 

Steps to take for installing OpenSSH server in Ubuntu system

1. Install OpenSSH Server

Run the following command to install OpenSSH server:

$ sudo apt-get install openssh-server

2. Enable SSH

Here, you will enable SSH to allow log in from remote machines by running the following command:

$ sudo systemctl enable ssh

3. Start SSH

Now start the ssh service by running the below command:

$ sudo systemctl start ssh

4. Test SSH Login

Now we will check whether we can access the server via ssh from a remote machine or not. To do that, log in to the system using your username and the IP address of the server machine.

$ ssh user@10.254.153.40

How to perform OpenSSH server configuration ?

1. SSH to remote server using bmc/kvm/ipmi over IP

We are using OpenPOWER based system known as Talos II from Raptor computing systems. Since it does not come with SSH server installed on it, this is how we will log in to bmc server to get access to the serial console:

$ ssh root@power9-bmc

2. Run obmc console

To get access to the Ubuntu server console, run the obmc-console-client by executing this command:

# obmc-console-client

To Install OpenSSH server on Ubuntu, follow the below steps:

1. Perform System Update and Upgrade

To begin,  update the system with the below command:

$ sudo apt update

After updating, upgrade the system by running the below command:

$ sudo apt upgrade

2. Install sshd server on Ubuntu

Here, we will install the openssh-server package by issuing the following command:

$ sudo apt install openssh-server

3. Check the status of the service

To verify whether the ssh service is running fine or not, simply Run the below command:

$ sudo systemctl status ssh

4. Enable and start SSH

Now, run the SSH service by first enabling it with the following command:

$ sudo systemctl enable ssh

Then Once the service is enabled, start the service by issuing the following command:

$ sudo systemctl start ssh

How to configure Firewall and open port 22 ?

We also need to allow SSH service through firewall. To do that, we will configure ufw, the firewall present in Ubuntu.

1. Allow SSH

To allow SSH on ufw, run this command:

$ sudo ufw allow ssh

2. Enable SSH

Next, we will enable SSH by running the following command:

$ sudo ufw enable

3. Check firewall status

Now check the status of the ufw firewall by running the following command:

$ sudo ufw status

How to Test SSH login ?

1. SSH to the OpenSSH server

You can now log in OpenSSH server from a desktop machine using SSH:

$ ssh user@10.254.153.40
$ ssh user@power9

2. Enable password less access

To allow password less login, you can copy and install the public key using ssh-copy-id command like this:

$ ssh-copy-id tom@power9

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