SSH (Secure Shell) is an encrypted network protocol used to access and manage a remote server over the internet. It is the secure replacement for unencrypted remote-access protocols such as Telnet.
With SSH you can connect to your server's command line, run administrative commands, manage files and services, and transfer data securely.
What SSH can be used for
- managing a remote Linux/Unix server through the command line;
- transferring files using SFTP or SCP;
- creating encrypted tunnels and forwarding ports between your computer and the server;
- authenticating with an SSH key pair instead of a password;
- forwarding X11 applications, where both sides are configured for it.
How SSH protects the connection
- the traffic is encrypted;
- the server is authenticated, so you can confirm you are connecting to the intended machine;
- the client is authenticated, by password or — preferably — by key pair;
- integrity checks detect whether transmitted data has been modified.
Together these reduce the risk of password interception, IP and DNS spoofing, and other man-in-the-middle attacks.
Connecting from Windows
PuTTY is a free SSH client for Windows. Download it only from the official project site: PuTTY download page.
- Open PuTTY.
- In Host Name (or IP address), enter your server's host name — vm00000.sayob.com, where vm00000 is your server's identifier — or its IP address.
- Set Port to
22, unless a different SSH port has been configured. - Select SSH as the connection type.
- Click Open.
- On the first connection PuTTY shows the server's host key fingerprint. Verify it against the fingerprint you were given, then accept it.
- Enter the user name for your server, for example
root. - Enter the password. Nothing is displayed as you type — this is normal, not a fault.
Recent versions of Windows also include an OpenSSH client, so you can connect from PowerShell or the command prompt with ssh [email protected] instead of installing anything.
Connecting from Linux or macOS
Both include an SSH client. In a terminal:
ssh [email protected]
Add -p and the port number if SSH is not on port 22.
Use keys rather than passwords
Once you have connected for the first time, set up key authentication and disable password login. A server reachable over SSH with a password is subject to continuous automated guessing attempts from the moment it goes online; keys remove that entire class of risk.
If you cannot connect
Check the host name and port first, then whether the network you are on permits outgoing connections on port 22 — some corporate and public networks block it. If the server refuses the connection rather than timing out, and the credentials are correct, the SSH service or the firewall on the server may be at fault.
If you have locked yourself out — a firewall rule or a broken SSH configuration — the IPMI console gives you access independently of the network: see What is IPMI (IP-KVM) and how do I connect to it?
If you still cannot get in, open a ticket from your client area.
