I want to connect my Linux server securely. Security is important nowadays. OpenSSH is a secure shell for remote connections. OpenSSH is very popular and have very life saver features.
Installation
Installation of ssh is like below. ssh full package name is Openssh-server which provides daemon, client and auxiliary tools for ssh.
Ubuntu, Debian, Mint, Kali:
$ sudo apt-get install openssh-server

CentOS, Fedora, RedHat:
$ sudo yum install openssh-server
Start Ssh Service
After installation if service is not started by default. We can start ssh
service with different methods but the most basic way is using init.d
system.
$ sudo /etc/init.d/ssh start

Get Status of Ssh Service
After the service is started we can check the service status with the status
command for init.d
. This will list some information like process ID, memory usage, CPU usage.
$ /etc/init.d/ssh status

Enable SSH Firewall Rule
Firewalls are used to protect servers for attacks.One of the main function is blocking port access. Default Ubuntu installation enables firewall named `ufw`. We will create a rule for `ufw` with the following command.
$ ufw allow ssh

Generate Ssh Key
SSH uses public and private keys. By default SSH do not generate SSH keys by default. We can create SSH keys with the ssh-keygen
like below.
$ ssh-keygen

We see from screenshot that RSA key pair is created by default. Created keys are stored in the user home .ssh
directory.
Connect SSH Server
Now we will made a test connection to the SSH server by providing the host name or IP address.
$ ssh 192.168.142.144

Ubuntu, Debian, Kali Ssh Installation Infografic
