Introduction to SSH

Last updated on 2018/01/18

Objective

SSH (Secure Shell) communication protocol is natively installed on all OVHcloud servers (VPS, dedicated servers, Public Cloud instances).

Learn how to use the SSH service to access your server.

Requirements

• SSH is installed on all machines. You can use it to connect securely to your server, and have full control over it.

Instructions

Compatible software

Many software applications enable you to connect via SSH. To help you, here are some examples.

On Windows

• PuTTY (Free)
• MobaXterm (free version and paid version)
• SecureCRT (Paid)

For the latest Windows 10 and Windows Server versions, developer mode gives you access to a bash console. Here is a link to the Microsoft documentation: https://docs.microsoft.com/fr-fr/windows/wsl/install-win10.

On Mac

• The Terminal tool is delivered with Mac OS X, and is systematically installed on the machine.

On Linux

• The Console or Terminal tool is natively installed, and can be used to connect.
• For managing multiple tabs, the Terminatorterminal emulator can be installed. You can read an Ubuntu manual page for Terminator here: http://manpages.ubuntu.com/manpages/zesty/man1/terminator.1.html.
• OpenSSH (Free).

Steps for connecting via SSH

Step 1: Connecting for the first time

To connect to your machine via SSH, you will need two details:

• the server’s IPv4 address or name;
• the server’s root password (received by email when it was set up).

You can connect using the following command:

ssh root@server_IP

Or this:

ssh root@server_name

The following message will appear:

The authenticity of host servername (server_IP) can’t be established.
RSA key fingerprint is a9:bb:55:35:86:xx:xx:00:xx:00:2b:2c:79:10:96:3c.
Are you sure you want to continue connecting (yes/no)? YES
[!warning] Permanently added servername, server_IP (RSA) to the list of known hosts.
Password:
root@vps12345:~#

When you first connect, your SSH client will receive an RSA key fingerprint, which is a fingerprint of the server you are connecting to. This is verified for each new connection. If the fingerprint changes, you will be informed, and this will mean something has changed:

• the machine has been reinstalled;
• the SSH server has been reinstalled;
• you are connecting to another machine.

When you first connect, you must accept the fingerprint that will be saved onto your desktop by your SSH client.

Step 2: the manual

On Linux distributions, you will have access to a manual with all of the commands available, and their arguments.

man bash

Step 3: updates

Both your SSH client and your distribution must be kept up-to-date. You can check this with the following command:

ssh -V

If you have any doubts, please refer to the documentation for the SSH client you are using.

Go further

Join our user community on https://community.ovh.com/en/.