i decided to modify Netomx script in order to monitor my VPS. I spent less than one hour on it, maybe i'll rewrite it in a few days if i find a major bug.
add to your crontab to run it every 5 or 10 minutes.
it has a quite a few improvements:
-) it's a bash script
-) first verifies the monitoring host is connected to the net
-) less false positive errors (a host must fail 2 scheduled run before triggering the alarm)
-) you get notifed only once, when a host goes up or down
-) simple, configurable and easy to modify short script
Your ideas and improvements are welcome!