The one checkbox that decides how you will reach your server
There is exactly one screen in the Ubuntu Server installer that experienced administrators never skip, and it contains exactly one checkbox: Install OpenSSH server. It is unticked by default, and leaving it unticked does not break anything - it just condemns you to running your shiny new server through a clumsy hypervisor console. This page explains what SSH is doing on a headless server, why the default is off, and how to fix it in one minute if you already missed it.
Ubuntu Server installs no graphical desktop - no windows, no browser, no mouse. Day to day, a server is used from a terminal on your own computer, connected over the network using SSH (Secure Shell). You type commands on your PC; they run on the server. File transfers, admin tools and scripts all ride on the same connection.
That makes the SSH server - the service that accepts those connections - the most important piece of software on the machine. Without it, the only way in is the ESXi console: a small windowed screen with no easy copy-paste, reached through your virtualization login. It works, but nobody wants to live there.
When the SSH setup screen appears during installation, Install OpenSSH server is not ticked. Ubuntu leaves it off because a service that is not installed cannot be attacked - a reasonable default for a distribution installed on everything from cloud instances to appliances. But for your server, on your host, the convenience of SSH is not optional. Tick the box.
Below it sits Allow password authentication over SSH. Leave it allowed for now. It lets you log in with the username and password you created on the profile screen, which is exactly how a first server should be reached while you learn.
The screen also offers to import an SSH identity from GitHub or Launchpad - that means copying a public key you have already published to one of those accounts, so you can log in with a key instead of a password. Keys are the stronger, more convenient option once you use them.
Honest guidance for a first install: if that last paragraph sounded like work, skip it without guilt. Password login plus a sensibly strong password is fine for learning and for a server on a private network. Key based login is a hardening step for later - it belongs to configuration, after the server exists, not to this screen under time pressure.
Forgot, rushed, or inherited a server where nobody ticked it? Nothing is ruined and there is no reason to reinstall. Log in at the ESXi console with your username and password, then run:
The package installs and the service starts automatically. Check it with sudo systemctl status ssh - you are looking for the word active. From that moment the server behaves exactly as if you had ticked the box during installation.
The complete installation on a live ESXi host - creating the virtual machine and working through the installer screens exactly as they appear.
Watch Full VideoNo. The installer shows an SSH setup screen with the Install OpenSSH server box unticked. If you press Continue without ticking it, the SSH server is not present after installation - but it can be added in about a minute with sudo apt install openssh-server.
From your own computer, open a terminal (Windows Terminal or PowerShell on a PC) and run ssh yourusername@server-address, for example ssh [email protected]. Confirm the fingerprint prompt the first time, then enter your password. You are now typing on the server.
Start with password login using a strong password, especially on a private home or office network. SSH keys are stronger and quicker once set up, and are the right hardening step once the server matters - but they are a configuration topic, not a reason to stall the installation.