Hung Q. Truong
Nov 5 · 3 min read

Set Up SSH Keys On Ubuntu 18.04

SSH is an encrypted protocol used to Admin and communicate with servers. When working with an Ubuntu server, most of your time in a terminal session connected to the server through SSH.

In this guide, I use a Pem file to SSH the server without password on Ubunto 18.04


To SSH using pem file, there are some of the following steps:

Step 1 — Create the Key Pair

The first step is to generate an RSA key pair by typing the following at a shell prompt:

After entering the command, you should see the following output:

Type ubuntu_ssh, You should then see the following prompt:

Press Enter (empty passphrase). Then You should then see the following output:

Then type:

Here we will get two files generated: ubuntu_ssh and ubuntu_ssh.pub . Then, rename ubuntu_ssh to ubuntu_ssh.pem, by typing:

So, you will have two files, ubuntu_ssh.pub and ubuntu_ssh.pem

Step 2 — Add Public Key to Ubuntu Server

Type this into your local computer, to get the public key:

Then, you should see the output like this:

Access your remote host using whichever method you have available. (Here I access via ssh with password)

Make sure the ~/.sshdirectory exists, if not exists, type this:

Create a file ~/.ssh/authorized_keys if already exist ignore this step

Then copy and paste your public key in to this file. — Save&Exit

Finally, need to change the permissions of the ~/.ssh/authorized_keys file using the following command:

Step 3— Using Key-Based Authentication

To improve the system security even further, you can enforce key-based authentication by disabling the standard password authentication. To do so, open up the SSH daemon’s configuration file:

In this file, change or uncomment if exist the option as follows:

To actually implement these changes, we need to restart the sshd service:

Step 4 — Now access the server by ssh through pem file ( without password ) from local

Finally, here is what we’re expecting:


Last by not least, I hope you find this useful!

Hung Q. Truong

Written by

Making useful things for life!

Welcome to a place where words matter. On Medium, smart voices and original ideas take center stage - with no ads in sight. Watch
Follow all the topics you care about, and we’ll deliver the best stories for you to your homepage and inbox. Explore
Get unlimited access to the best stories on Medium — and support writers while you’re at it. Just $5/month. Upgrade