By using SSH keys, we can log into Linux without a password (and this is the recommended approach). This way, you won’t need to enter a password every time you SSH to Linux.

Generating Key Pairs

  • You can generate keys anywhere - on the client, server, or third party. Even in Vaultwarden for easy management, as long as you keep them secure. On Windows/Mac/Linux, enter:

    ssh-keygen

  • Keys are typically generated in C:\Users\Username\.ssh\. A public key (id_rsa.pub or id_ed25519.pub) and a private key are created as a pair.

Server Side

  • The server needs to keep the public key. The client keeps the private key (which must not be exposed).

  • Check if there’s a .ssh directory in Linux. If not, create it:

    cd ~
mkdir -p ~/.ssh
chmod 700 ~/.ssh

  • Upload the public key to Linux, or copy and paste directly:

    cd C:\Users\Username\.ssh\
scp .\id_rsa.pub username@address:~/.ssh
scp .\id_ed25519.pub username@address:~/.ssh

  • Check if there’s an authorized_keys file in Linux. If not, create it:

    cd ~/.ssh
touch authorized_keys
chmod 600 ./authorized_keys
cat id_rsa.pub >> ./authorized_keys
cat id_ed25519.pub >> ./authorized_keys

  • After adding, you can delete the public key files:

    cd ~/.ssh
rm id_rsa.pub
rm id_ed25519.pub

Client Side

  • You can specify key pairs in the config file on the client. On Windows, this is at C:\Users\Username\.ssh\config:

    Host host1											# Server hostname
  HostName hostname1 								# Server IP or URL
  User admin										# User
  IdentityFile "C:\Users\Username\.ssh\id_ed25519"	# Local private key path
Host host2
  HostName hostname2
  User admin
  IdentityFile "C:\Users\Username\.ssh\id_pem"

  • If not specified, it defaults to using the id_ed25519 private key. Note that one id_ed25519 file can only contain one private key.

After configuration, you can log into Linux without a password.