Edward L. Haletk wrote a nice write up at http://searchvmware.techtarget.com/home/0,289692,sid179,00.html titled Keep your VMware ESXi warranty: Don’t break the security shell
Working with VMware ESXi can be frustrating; you’re not supposed to enable the Dropbear SSH client or use its technical support mode without the assistance of a VMware support representative. System administrators, however, may be tempted to use tech support mode (or enable Dropbear) to fix problems or manage connections on the fly. Cracking this security shell, however, can void the VMware ESXi warranty and break support contracts. In this tip, I’ll explain alternatives that allow you to manage your ESXi virtual machines without compromising its security — and possibly breaking a support contract.
This is one of those subjects that has two points of view, you either see security as a high concern, or you don’t. In my eyes, if you have your network setup correct, the proposal of having a SSH login isn’t a major concern. However, the lack of warranty because of this is alarming to me.
I would like to discuss this further, if anyone is up to the conversation contact me.