With Nagios using check_icmp is the way to go, it better and faster, below is an example configuration directive for setting the check-host-alive command which will be used by each host check.

# 'check-host-alive' command definition
define command{
command_name    check-host-alive
command_line    $USER1$/check_icmp -H $HOSTADDRESS$ -w 30,5% -c 100,20% -p 1
}