selectively route traffic in split-VPN 12.04

Question

I often work remotely. I use the Network Manager to set up my VPN connection, which has worked pretty well. The VPN I have set up currently using the Password with Certificates (TLS) type. What I want to do is only route certain traffic through the VPN, and all other traffic over the normal local internet connection.
Is this possible?

Just to help explain my situation I will give an example of the type of connections I usually have to make with the VPN network. We have an "intranet" web site set up on our work network, so this web site is only accessible to me when I use VPN, but is accessed the same way I access other sites, like Google or askubuntu.com. I often connect to a desktop computer over the VPN connection via remote desktop, where I enter the name )IP Address) of the desktop computer, username, and password. I connect to a MySQL server using MySQL Workbench, where you enter an IP address, username and password. I often connect to linux servers using SSH.

For all of the above connections I need the VPN. However I also do some normal web surfing, as well as connecting to resources outside of the work network (Gmail, Stack Overflow, Gaming, etc.). For these connections I wish not to access via the VPN connection because these connections do not need my VPN, the VPN just makes this much slower.

I have tried the technique describe in this link: http://darrenwatt.com/split-tunnel-ubuntu/

This did not seem to work for me. Specifically, I couldn't connect to the "intranet" site after checking the "Use this connection only for resource on its network" check box and connection the VPN.

Does anyone know how I can selectively route traffic through the VPN? Does this make sense?

Thanks!!

Answer 1

I don't know how this work with NM but I write script

#!/bin/bash
function routeadd {
    route add -host xxx.xxx.xxx.xxx dev ppp0
    route add -net xxx.xxx.xxx.xxx/xx dev ppp0
}
function makepptp {
   echo pty \"pptp xxx.xxx.xxx.xxx --nolaunchpppd\" >> /etc/ppp/peers/vpn;
   echo remotename PPTP >> /etc/ppp/peers/vpn;
   echo require-mppe-128 >> /etc/ppp/peers/vpn;
   echo file /etc/ppp/options.pptp >> /etc/ppp/peers/vpn;
   echo ipparam vpn >> /etc/ppp/peers/vpn;
pppd call vpn &
}
if [ -a /etc/ppp/chap-secrets ];
        then
        rm /etc/ppp/chap-secrets
    echo $1 PPTP $2 '*' >> /etc/ppp/chap-secrets;
else
    echo $1 PPTP $2 '*' >> /etc/ppp/chap-secrets;
fi

if [ -e /etc/ppp/peers/vpn ];
    then
    rm /etc/ppp/peers/vpn;
    echo name $1 >> /etc/ppp/peers/vpn;
    makepptp;
    sleep 8;
    routeadd;
else
    echo name $1 >> /etc/ppp/peers/vpn;
    makepptp;
    sleep 8;
    routeadd;
fi

Usage:

sudo /path_to_script/vpn username password

note: set execute permision to script

Traffic is routed via vpn only if you add route, anything else go default gw.