VPN Ubuntu 12.04 x64 Server

#!/bin/bash
echo "Select on option:"
echo "1) Set up new PoPToP server AND create one user"
echo "2) Create additional users"
read x
if test $x -eq 1; then
    echo "Enter username that you want to create (eg. client1 or john):"
    read u
    echo "Specify password that you want the server to use:"
    read p
 
# get the VPS IP
ip=`ifconfig eth0 | grep 'inet addr' | awk {'print $2'} | sed s/.*://`
 
echo
echo "Downloading and Installing PoPToP"
apt-get update
apt-get install pptpd
 
echo
echo "Creating Server Config"
cat > /etc/ppp/pptpd-options <<END
name pptpd
refuse-pap
refuse-chap
refuse-mschap
require-mschap-v2
require-mppe-128
ms-dns 8.8.8.8
ms-dns 8.8.4.4
proxyarp
nodefaultroute
lock
nobsdcomp
END
 
# setting up pptpd.conf
echo "option /etc/ppp/pptpd-options" > /etc/pptpd.conf
echo "logwtmp" >> /etc/pptpd.conf
echo "localip $ip" >> /etc/pptpd.conf
echo "remoteip 10.1.0.1-100" >> /etc/pptpd.conf
 
# adding new user
echo "$u	*	$p	*" >> /etc/ppp/chap-secrets
 
echo
echo "Forwarding IPv4 and Enabling it on boot"
cat >> /etc/sysctl.conf <<END
net.ipv4.ip_forward=1
END
sysctl -p
 
echo
echo "Updating IPtables Routing and Enabling it on boot"
iptables -t nat -A POSTROUTING -j SNAT --to $ip
# saves iptables routing rules and enables them on-boot
iptables-save > /etc/iptables.conf
 
cat > /etc/network/if-pre-up.d/iptables <<END
#!/bin/sh
iptables-restore < /etc/iptables.conf
END
 
chmod +x /etc/network/if-pre-up.d/iptables
cat >> /etc/ppp/ip-up <<END
ifconfig ppp0 mtu 1400
END
 
echo
echo "Restarting PoPToP"
/etc/init.d/pptpd restart
 
echo
echo "Server setup complete!"
echo "Connect to your VPS at $ip with these credentials:"
echo "Username:$u ##### Password: $p"
 
# runs this if option 2 is selected
elif test $x -eq 2; then
    echo "Enter username that you want to create (eg. client1 or john):"
    read u
    echo "Specify password that you want the server to use:"
    read p
 
# get the VPS IP
ip=`ifconfig venet0:0 | grep 'inet addr' | awk {'print $2'} | sed s/.*://`
 
# adding new user
echo "$u	*	$p	*" >> /etc/ppp/chap-secrets
 
echo
echo "Addtional user added!"
echo "Connect to your VPS at $ip with these credentials:"
echo "Username:$u ##### Password: $p"
 
else
echo "Invalid selection, quitting."
exit
fi