How to Set Up Password-less SSH Login on a Linux Machine

Do you log in to your Linux server frequently? Tired of entering your password every time? With SSH key-based authentication, you can streamline your workflow by logging in securely without a password.

In this guide, we’ll show you how to set up password-less SSH login in just two steps using ssh-keygen and ssh-copy-id.

What Is Password-less SSH Login?

Password-less SSH login uses public key cryptography to authenticate your access. Instead of typing a password, you use an SSH key pair—one private (stored on your machine) and one public (stored on the server). It’s fast, convenient, and much safer than using passwords alone.

Step 1: Generate an SSH Key Pair

Open a terminal on your local machine and run:

ssh-keygen

You will be prompted:

Generating public/private rsa key pair.
Enter file in which to save the key (/home/yourname/.ssh/id_rsa):

Simply press Enter to accept the default location.

When asked for a passphrase, you can either:

Press Enter again for a completely password-less login
Or enter a secure passphrase for additional protection

This will generate two files:

~/.ssh/id_rsa (your private key – keep this secret!)
~/.ssh/id_rsa.pub (your public key – safe to share with the server)

Step 2: Copy the Public Key to Your Server

Run the following command to upload your public key to the remote server:

ssh-copy-id username@server_ip

Replace:

username with your actual Linux username on the remote server
server_ip with your server’s IP address or domain

You’ll be asked to enter your server password one last time. Once complete, the public key will be added to the server’s ~/.ssh/authorized_keys file.

Step 3: Test the Password-less Login

Now try logging in again:

ssh username@server_ip

If everything went well, you’ll log in without needing to enter your password!

🔍 Behind the Scenes: How It Works

Here’s what’s happening:

Your SSH client sends a request to the server.
The server checks for your public key.
If it finds a match, it issues a challenge.
Your private key answers the challenge.
The server validates the answer and grants access—no password required!

Best Practices & Tips

Keep your private key secure. Do not share it.
Set correct file permissions:

  chmod 700 ~/.ssh
  chmod 600 ~/.ssh/authorized_keys

Use a passphrase on your key for additional security.
Consider backing up your keys in a secure, encrypted location.

Extra tip:

Create alias which contain the command to ssh to you remote server:

alias pi = “ssh username@ipaddress”

Now you will be able to connect to your remote server just by typing pi.

To keep this alias permanently on your system add it to your bash settings file.

Conclusion

That’s it! In just a few minutes, you’ve set up a secure, password-less SSH login. This small tweak can save you time and improve your server’s security. Whether you’re managing personal servers or enterprise systems, SSH keys are the way to go.

Happy logging in—no password required! 🧑‍�