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.
1 | root@ubu1:~# apt-get install openssh-server |
Start Ssh Service
After installation if service is not started we can start the service like below.
1 | root@ubu1:~# /etc/init.d/ssh start |
Get Status of Ssh Service
We can get status of ssh service with the following command
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | root@ubu1:~# /etc/init.d/ssh status ● ssh.service - OpenBSD Secure Shell server Loaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enabled) Active: active (running) since Tue 2016-11-01 05:06:03 +03; 1 day 11h ago Main PID: 3309 (sshd) Tasks: 1 (limit: 4915) Memory: 2.9M CPU: 6ms CGroup: /system.slice/ssh.service └─3309 /usr/sbin/sshd -D Nov 01 05:06:03 ubu1 systemd[1]: Starting OpenBSD Secure Shell server... Nov 01 05:06:03 ubu1 sshd[3309]: Server listening on 0.0.0.0 port 22. Nov 01 05:06:03 ubu1 sshd[3309]: Server listening on :: port 22. Nov 01 05:06:03 ubu1 systemd[1]: Started OpenBSD Secure Shell server. |
Create Firewall Rule
We need to accept tcp port 22 connection in our firewall. We can add this rule to the firewall like below.
1 2 3 | root@ubu1:~# ufw allow ssh Rules updated Rules updated (v6) |
Generate Ssh Key
We need to generate key to encrypt ssh traffic.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 | root@ubu1:~# ssh-keygen Generating public/private rsa key pair. Enter file in which to save the key (/root/.ssh/id_rsa): Created directory '/root/.ssh'. Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /root/.ssh/id_rsa. Your public key has been saved in /root/.ssh/id_rsa.pub. The key fingerprint is: SHA256:/hx/xaVWjtEJD1ZyeHohFdMy83b/CWEQ6Kclhh88Srw root@ubu1 The key's randomart image is: +---[RSA 2048]----+ | ....+*o| | . . **oo| | . + o B*o| | + B o +.+B| | . S B . oO+| | E o .+ =| | . . ...o| | o o ...| | o .. | +----[SHA256]-----+ |
