Вариант 1

#!/bin/sh
date=`date '+%d.%m.%Y %H:%M:%S'`
/sbin/ping -nq -c 3 -i 2 192.168.0.1 > /dev/null
if [ $? -ne 0 ] ; then
echo $date' ping error' >> /var/log/vpnlog.log
/usr/local/etc/rc.d/mpd4 restart
pfctl -f /etc/pf.conf
else
echo $date' ping…ok!' >> /var/log/vpnlog.log
fi

Вариант 2

#!/bin/sh

png=`ping -c 1 -i 1 192.168.0.1 | grep % | awk '{ print $7 }'`;
date=`date '+%d.%m.%Y %H:%M:%S'`;
echo $png
case $png in
100.0%)
echo $date' ping error!… reload VPN' >> /var/log/vpn.log
/usr/local/etc/rc.d/mpd4 restart
break
;;
0.0%)
echo «ok»
echo $date' ping OK!…' >> /var/log/vpn.log
break
;;
*)
echo «prosel kanal»
echo $date' ping govno!…' $png >> /var/log/vpn.log
break
;;
esac

И запускаем по крону…