系统要求：CentOS 5 32bits/64bits。

使用方法：

# wget http://www.diahosting.com/dload/pptpd.sh
# sh
pptpd.sh

安装完成后会提示vpn用户名和密码。

VPN用户管理：
直接编辑/etc/ppp/chap-secrets文件，按照相同格式添加用户名和密码即可。

PS:使用此一件安装包后,iptables和pptpd服务会随开机启动!

附脚本（pptpd.sh）源码以便学习（注意：以下所有标点符号均为英文输入状态下的符号，如有中文符号，请自行更改。）：

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

wget http://www.diahosting.com/dload/dkms-2.0.17.5-1.noarch.rpm
wget http://www.diahosting.com/dload/kernel_ppp_mppe-1.0.2-3dkms.noarch.rpm
wget http://www.diahosting.com/dload/pptpd-1.3.4-1.rhel5.1.i386.rpm
wget http://www.diahosting.com/dload/ppp-2.4.4-9.0.rhel5.i386.rpm

yum -y install make libpcap iptables gcc-c++ logrotate tar cpio perl pam tcp_wrappers
rpm -ivh dkms-2.0.17.5-1.noarch.rpm
rpm -ivh kernel_ppp_mppe-1.0.2-3dkms.noarch.rpm
rpm -qa kernel_ppp_mppe
rpm -Uvh ppp-2.4.4-9.0.rhel5.i386.rpm
rpm -ivh pptpd-1.3.4-1.rhel5.1.i386.rpm

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

echo “vpn 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 service is installed, your VPN username is vpn, VPN password is ${pass}”