Setting a PPTP VPN in CentOS 5.6

Setting a PPTP VPN in Centos. I’m using the following commands in order to set the VPN:

yum remove -y pptpd ppp
iptables --flush POSTROUTING --table nat
iptables --flush FORWARD
rm -rf /etc/pptpd.conf
rm -rf /etc/ppp

rpm -Uvh http://poptop.sourceforge.net/yum/stable/rhel5/pptp-release-current.noarch.rpm
yum --enablerepo=poptop-stable install pptpd

mknod /dev/ppp c 108 0
echo 1 > /proc/sys/net/ipv4/ip_forward
echo "mknod /dev/ppp c 108 0" >> /etc/rc.local
echo "echo 1 > /proc/sys/net/ipv4/ip_forward" >> /etc/rc.local
echo "localip 172.16.36.1" >> /etc/pptpd.conf
echo "remoteip 172.16.36.2-254" >> /etc/pptpd.conf
echo "ms-dns 8.8.8.8" >> /etc/ppp/options.pptpd
echo "ms-dns 8.8.4.4" >> /etc/ppp/options.pptpd

pass=`openssl rand 6 -base64`
if [ "$1" != "" ]
then pass=$1
fi
read -p "User: " user
echo "${user} pptpd ${pass} *" >> /etc/ppp/chap-secrets

iptables -t nat -A POSTROUTING -s 172.16.36.0/24 -j SNAT --to-source `ifconfig | grep 'inet addr:'| grep -v '127.0.0.1' | cut -d: -f2 | awk 'NR==1 { print $1}'`
iptables -A FORWARD -p tcp --syn -s 172.16.36.0/24 -j TCPMSS --set-mss 1356
service iptables save

chkconfig iptables on
chkconfig pptpd on
service iptables start
service pptpd start

echo "VPN username is ${user}, VPN password is ${pass}"