Accessing remote systems with ssh; logging in and switching users (su -, sudo -i) in multiuser targets

RHEL servers usually run in the multi-user target, a text-mode state with networking and services running but no graphical desktop. You reach them with a text console or, far more often, over the network with SSH (Secure Shell), which encrypts the whole session. On the exam you will ssh between machines and switch between accounts constantly, so these commands should become automatic.