Alerts for servers going down

Hello,
I am doing some research on my own, but wanted to ask out here to see if anyone is using something to notify them if a server, router, etc.. goes down. I have a security camera server setup on ups, and auto restart and login in case of power failure, but even that doesnt alway do the trick. I was wondering if there was a good piece of software out there that could run on a pc inside the network that can alert/notify admins when hardware goes down. Im guessing it would be something that just send a ping request out there during a time you specify, and if there is no reply it would send off any email to the admin. Any help or recommendations would really be appreciatead. thanks.