Using ssh keys to administer remote devices is a must, In this guide we will be using two machines, the first machine the client is running parrot OS a Linux pen testing operating system and the second machine is running Ubuntu server 18.04.
First things first on the client machine open up a terminal and as always check for updates. We will also make sure the necessary packages are installed
sudo apt update && sudo apt upgrade && sudo apt install openssh-server
Once the system is done updating and installing the required packages we can proceed to create the public and private keys from the users home directory
cd ~/ ssh-keygen -t rsa -b 4096 -C client-machin
When it prompts you to enter a file in which to save the keys press enter to accept the default location, It will now prompt you to enter a password to protect the key file , you can hit enter to bypass setting a password, I normally don’t use a password for my keys that way i can ssh into remote machines without the hassle of typing out a password.
Now that we have successfully created our key pair we need to send the public key to the remote server.
Sending the id_rsa.pub key to the server can be achieved with a simple command.
ssh-copy-id -i $HOME/.ssh/id_rsa.pub user@servers-ip
If everything went as planed we can now ssh into our server machine via the client machine without having to type in a password.