Stuff

vpnserver="192.168.10.2" 
RED_DEV="ppp0" 
/sbin/iptables -N pptp 
/sbin/iptables -A pptp -p tcp --destination-port 1723 --dst $vpnserver -j ACCEPT 
/sbin/iptables -A pptp -p 47 --dst $vpnserver -j ACCEPT 
/sbin/iptables -I FORWARD -j pptp 
/sbin/iptables -t nat -N pptp 
/sbin/iptables -t nat -A pptp -i $RED_DEV -p tcp --dport 1723 -j DNAT --to vpnserver:1723 
/sbin/iptables -t nat -A pptp -i $RED_DEV -p 47 -j DNAT --to $vpnserver 
/sbin/iptables -t nat -A PREROUTING -j pptp