How to “auto reboot” server if the server don’t come online by itself

Hi !

First of all, sorry for my bad english, i’m French.

I’m the owner of a g-portal server and sometimes, after auto restart, the server don’t go online by itself. Sometime crash happens too, and if i’m not online or not available, the server won’t go online back. I always have to go in g portal by myself to make it online again. Is there anyway to custom something like “auto ping” all 15 mins, and if server can’t ping himself he will reboot ?