SSH configuration files¶

Setting up an SSH configuration file allows you to simplify connecting to the server - rather than having to include all the different options when you run the ssh command, we can define all of these in the configuration file and then initiate a connection with less effort.

If you setup a connection using Visual Studio Code then this will have already created a configuration file for you.

File location¶

Your configuration file is a text file called config, which lives inside the .ssh directory in your home/user directory.

C:\Users\<username>\.ssh\config

/Users/<username>/.ssh/config

/home/<username>/.ssh/config

C:\Users\<username>\OneDrive - UWE Bristol\.ssh\config

Open or create this file using a text editor (like Visual Studio Code).

Standard format¶

The configuration file follows a standard format - a Host block for each machine we want to be able to connect to using SSH, with a set of directives which define how this connection should be setup.

A very simple configuration file would look like this:

Host csctcloud
    Hostname csctcloud.uwe.ac.uk
    User a.student@live.uwe.ac.uk

A connection can then be launched by referencing the relevant Host in the SSH connection command, without any additional arguments required:

ssh csctcloud

Specifiying an SSH key¶

Unless you specify otherwise, the SSH program will try to authenticate you to the server using keys stored in a standard way - saved in the .ssh folder in your home/user profile, and named after one of the available key algorithms that can be used to generate them.

The IdentityFile directive is used to specify the private key file that should be presented when it is saved in a non-standard location, or named differently. Set this directive to point to the correct private key to use.

IdentityFile ~/.ssh/csctcloud