What is SSH?

The Secure Shell (SSH) protocol

SSH is a cryptographic network protocol used for secure access to a networked computer. The data transmitted between the client and server is protected with strong encryption algorithms, ensuring privacy and data integrity.

All FluidStack instances run SSH servers for remote access. These servers authenticate using SSH keys.

About SSH keys

For improved security, we use public-key cryptography for authentication instead of a password. This is also known as SSH key authentication. This method requires that you provide your own public/private key pair.

Your public key is stored on your instance as your SSH key, when the instance is created. Its corresponding private key is stored locally on the computer that you use to access your instance. SSH access is granted by verifying that your private key corresponds to the public key. As an analogy, think of a public key as a lock that only your private key can unlock.

Tip
Public/private key pairs are used for many purposes, not only SSH. For example, they are used in file encryption, digital signatures, and cryptocurrency transactions.

SSH clients

An SSH client is used to remotely connect to an instance. Nearly all computers have an SSH client installed by default. To test if you have one installed, enter the following command in your CLI shell:

$ssh -v

You should see a list of usage options. If you see an output indicating that the command was not found, install an SSH client. Two popular options are OpenSSH and Putty.

What’s next?

  • In our guide How to use SSH keys, learn how to generate an public/private key pair and use it to connect to an instance.