Normally, I make ssh connections to ESX using an ssh client such as Putty or Bitvise Tunnelier. Out of the box, ESX enables ssh access but disallows login as root. To perform tasks as root, you have to logon with a regular user account and then get root privileges with su. This means you have to type two passwords each time, which is annoying. Using passwords is also a less secure way of connecting and with ESX, security is a top concern.

So, instead of using passwords, you can authenticate by using key pairs. The full process is explained in a very well written tutorial you can find here. In short, the steps are as follows:

• Generate a public/private key pair
• Put the public key on the server (ESX)
• Configure your client (e.g. Putty) to use the private key to authenticate
• (optionally) Use Pageant to avoid having to type the pass phrase to the private key each time you logon

On my system, all I have to do is to click an icon on my desktop that connects to the target ESX server. Then Putty opens and logs me on automatically to the ESX server:

If you want, you can also disable the use of passwords and require that everyone use a private key to authenticate. Less flexible, but more secure!