Enabling SSH

This next step is to enable SSH so you can access and manipulate the data from your windows machine. This is handy for adding ROMs or backing up data etc. For this step I would recommend plugging in a mouse and keyboard since we will be using desktop mode.
To access desktop mode press the steam button on the deck and go to power then select Switch to desktop. Once the desktop is loaded click the deck icon in the bottom left hand corner and type Konsole and press enter or you can click system and then click konsole. This will open the Terminal aka Konsole. Here you will type

passwd

and press Enter. It will then ask you to enter a password of your choosing for the deck user and press enter. You will need to enter this password again to confirm and press enter once more. It should say “password updated successfully”
(Note: When using the sudo command it may prompt you for the password you just created)
Next you will want to start the SSH server by typing

sudo systemctl start sshd

If you would like to enable the SSH server automatically whenever the deck is restarted type

sudo systemctl enable ssh

If you do not want it to start automatically you will need to enter the command “sudo systemctl start sshd” each time you would like to connect after rebooting the Deck.
Lets now add some things to the SSH configuration for added security. To edit the config file type

sudo nano /etc/ssh/sshd_config

The above command will open the config file for editing. Add these 2 lines to the file. The first line limits you to only be able to connect to it over a local network and the second line makes sure no one can login as root.

AllowUsers deck@192.168.0.0/16 PermitRootLogin no

You can add these lines anywhere but I like to add them to the # Authentication section. Just scroll down a bit until you see # Authentication and add the lines above
Once those lines are added you can press “CTRL X” to exit then it will ask if you want to save modified buffer press “Y” then press enter to keep the file name the same. Now we simply need to restart the SSH server for the changes to take effect by typing

sudo systemctl restart sshd

I used this guide for reference https://chryseus.co.uk/setting-up-ssh-sftp-on-steam-deck/