vpn_pptp.sh

    #!/bin/bash
    #===============================================================================================
    #   System Required:  Debian or Ubuntu (32bit/64bit)
    #   Description:  Install PPTP VPN for Debian or Ubuntu
    #   Author: mikangchan <[email protected]>
    #   More Info: http://ovo.so
    #===============================================================================================
    clear
    echo "#############################################################"
    echo "# Install pptp vpn for Debian or Ubuntu (32bit/64bit)"
    echo "#"
    echo "# Author: mikangchan <[email protected]>"
    echo "#"
    echo "#############################################################"
    echo ""
    function check_sanity {
        # Check whether is available to install.
        if [ $(/usr/bin/id -u) != "0" ]
        then
            die 'Run under root user'
        fi

        if [ ! -f /etc/debian_version ]
        then
            die "You are not using a Supported Debian or Ubuntu"
        fi
    }

    function die {
        echo "ERROR: $1" > /dev/null 1>&2
        exit 1
    }
    function installVPN(){
        apt-get update
        rm -rf /etc/pptpd.conf
        rm -rf /etc/ppp
        apt-get -y --force-yes remove ppp pptpd 
        
        apt-get -y --force-yes install ppp pptpd iptables curl crudini
        
        echo ms-dns 208.67.220.220 >> /etc/ppp/pptpd-options
        echo ms-dns 208.67.222.222 >> /etc/ppp/pptpd-options
        echo localip 192.168.90.1 >> /etc/pptpd.conf
        echo remoteip 192.168.90.10-32 >> /etc/pptpd.conf
        
        IP=`curl -s checkip.dyndns.com | cut -d' ' -f 6  | cut -d'<' -f 1`
        if [ -z $IP ]; then
        IP=`curl -s ifconfig.me/ip`
        fi
        
        iptables -t nat -A POSTROUTING -s 192.168.90.0/24 -j SNAT --to-source $IP
        sed -i 's/exit\ 0/#exit\ 0/' /etc/rc.local
        
        echo iptables -t nat -A POSTROUTING -s 192.168.90.0/24 -j SNAT --to-source $IP >> /etc/rc.local
        echo exit 0 >> /etc/rc.local
        crudini --set /etc/sysctl.conf '' 'net.ipv4.ip_forward' '1'
        sysctl -p
        /etc/init.d/pptpd restart
    }

    function uninstallVPN(){
        echo "begin to uninstall VPN";
        apt-get -y --force-yes remove ppp pptpd 
        sed -i '/192.168.90.0/d' /etc/rc.local 
        sed -i '/net.ipv4.ip_forward/d' /etc/sysctl.conf
        sysctl -p
    }
    function repaireVPN(){
        echo "begin to repaire VPN";
        mknod /dev/ppp c 108 0
        /etc/init.d/pptpd restart
    }

    function adduser(){
        echo "input username:"
        read username
        echo "input password:"
        read userpassword
        echo "${username} pptpd ${userpassword} *" >> /etc/ppp/chap-secrets
        /etc/init.d/pptpd restart
    }

    ######################### Initialization ################################################
    # Make sure only root can run this script
    check_sanity
    action=$1
    [  -z $1 ] && action=install
    case "$action" in
    install)
        installVPN
        ;;
    uninstall)
        uninstallVPN
        ;;
    repaire)
        repaireVPN
        ;;
    adduser)
        adduser
        ;;  
    *)
        echo "Arguments error! [${action} ]"
        echo "Usage: `basename $0` {install|uninstall|update}"
        ;;
    esac