If you are setting up SSH public key authentication in a new Fedora/CentOS install, you must make sure the SELINX configuration is setup correctly for the /root/.ssh folder on the server.

The ~.ssh/ folder is not created on a new install. If you manually create the folder, set the SELINUX permissions with this command:

restorecon -R -v /root/.ssh

Another tip: If you are using the PuTTY Key generator to generate the public key, make sure you copy and paste the text into a single line in the /root/.ssh/authorized_keys file. Each line of the authorized_keys file should have the following: ssh-rsa (key contents) imported-openssh-key

If you ssh into your server and the text is stuck at 80 characters per line, you will need to check the sshd setting in /etc/ssh/sshd_config (Debian)

Make sure the X11 setting is set to yes. This will allow you to expand your terminal window to beyond 80 characters per line.  Otherwise, it will be limited to the display settings in console.

X11Forwarding yes