ssh-keygen

Owned by Mike Tango Bravo
Feb 06, 2022
1 min read

  1. On host_src,
    run this command as the user that runs scp/ssh/rsync

    $ ssh-keygen -t rsa

    This will prompt for a passphrase. Just press the
    enter key. It'll then generate an identification (private key) and a
    public key. Do not ever share the private key with anyone!ssh-keygen shows
    where it saved the public key. This is by default ~/.ssh/id_rsa.pub:

    Your
    public key has been saved in <your_home_dir>/.ssh/id_rsa.pub

 

  1. Transfer the id_rsa.pub file to host_dest by either ftp, scp, rsync or any other method.

 

  1. On host_dest,
    login as the remote user which you plan to use when you run scp,ssh or rsyn con host_src.

  2. Copy the contents
    of id_rsa.pub to ~/.ssh/authorized_keys

$ cat id_rsa.pub >>~/.ssh/authorized_keys $ chmod 700 ~/.ssh/authorized_keys $ chmod 700 .ssh

If this file does not exist, then the above command will create it. Make sure you remove permission for others to read this file. If its a public key, why
prevent others from reading this file? Probably, the owner of the key has distributed it to a few trusted users and has not placed any
additional security measures to check if its really a trusted user.

  1. Note that ssh
    by default does not allow root to log in. This has to be explicitly
    enabled on host_dest.
    This can be done by editing /etc/ssh/sshd_config
    and changing the option of PermitRootLogin
    from no
    to yes.
    Don't forget to restart sshd so that it reads the modified config file. Do this only
    if you want to use the root login.

 

Configure sudo

Use the usermod command to add the user to the wheel group.

usermod -aG wheel username

By default, on CentOS, members of the wheel group have sudo privileges.