Write Linux command used.

$**$Suppose that you have an administrator user on servera called Admin$\_$A that has the password Adm!n@$,120$

Connect to servera via ssh by using the credentials provided above $($username and password$)$

Generate passphrase SSH keys for your device. The passphrase id ReDHat

Send the public key of the SSH key pair to servera.

Connect to servera via ssh using the passphrase.

Start the ssh$-$agent program manually, then add the private keys from a file $\frac{}{.}ss\frac{h}{k}ey$ pass.

Configure sshd on servera to prevent users logging in as root.

Configure sshd on servera to allow users to authenticate with SSH keys only.