Reboot server if connection lost (credit to http://ubuntuforums.org/archive/index.php/t-1889951.html)

simple_monitor.sh

#!/bin/bash
HOSTS="router"
COUNT=4
for myHost in $HOSTS
do
  count=$(ping -c $COUNT $myHost | grep 'received' | awk -F',' '{ print $2 }' | awk '{ print $1 }')
  echo "Ping count of $count to $myHost at $(date)" >> ~/log/monitor.log
  if [[ $count == '' ]]; then
    echo "Host : connection is down (ping failed) at $(date)" >> ~/log/monitor.log
    reboot
  fi
  if [ $count -ne 4 ]; then
    # partial fail
    echo "Host : $myHost is only partially connectable (ping failed) at $(date)" >> ~/log/monitor.log
    reboot
  fi
done