thank you for the answers.
i found an option in the esx cluster: vm monitoring. as I searched in the documentation, maybe this feature could help. no vm hb received, make a vm reboot. i tested, but I couldn't make this feature take any action. i just enabled the vm monitoring, so after a 30seconds lost of network it should reset the vm - as I understand the manual. but this did not happen.
do you have any experience about this?