Enabling SSH on ESX hosts is easy however you have to do it so little that it is easy to forget.
In the VSphere client go to the “Configuration” tab and select “Security Profile” from the left hand menu, in the top right hand corner of the security profile window click “Properties”.
From here you will be able to click “Start” and that will start “SSH” on your host, it is very important not to leave this enabled when you are not using it so when you are done repeat the process and click stop.
In Linux or OSX you can open “Terminal” and run the following command in order to access the host. Just replace HOST_IP with the IP Address of your host
ssh -l root HOST_IP
In Windows you can use an application like Putty to access your host.