I recently installed 2 ESXi 5 servers into my lab to assist with my ESXi 5 certification update. In my home lab i do not have a spare monitor so each time i have to display the console i have to unplug the monitor from my main PC and plug it in which is a pain. Whilst installing ESXi i forgot to enable remote tech support mode which meant that i could not connect remotely to the console via SSH.
Luckily i found you can achieve the same result through the client.
All you have to do is connect to the server in question via the client and go to the configuration tab in hosts and clusters view, and then select Security profile. From there select Properties. The two options we need to enable are ESXi Shell and SSH. Click on options and select start automatically.
You should now be able to connect from an SSH client like putty