So you want to SSH into your ESXi or ESX box, and be all techy looking and use putty so you know what you are doing when the boss comes around. [Hahahahaha].
Step 1: First you must login as a root at the console of your ESX 4 server.
Step 2: Then you must navigate to the /etc/ssh directory. Just type in: cd /etc/ssh
Step 3: Open nano (text editor, easy to use…) type: nano sshd_config
Navigate to the line saying PermitRootLogin no and change it to Yes.
Step 4: Type then CTRL + X to exit. On the prompt answer Y (as Yes to save the modified file).
Step 5: Then you’ll need to restart the sshd service typing: service sshd restart
Step 6: While you are in the console just type in the following two commands to open firewall ports:
esxcfg-firewall -e sshServer
esxcfg-firewall -e sshClient