I see thousands of failed login attempts on our servers and want to do what I can to prevent a successful one from the bad guys. I want to block anyone not originating from a /29 block we own from being allowed to SSH into our servers.
I have disabled root login, password authentication, installed fail2ban, and instituted SSH keys. Is this a redundant step or a decent layer of protection? If the later, what is a way I can achieve this?