I have setup my VPN client (VPNC Front End) to use split tunneling. After the VPN is connected, I have a script which adds the routes for all of the IP addresses that I know should be routed through the VPN.
Now and then, I bump into IP addresses which are not routed through the VPN and hence are not accessible from the outside either. Using a multi-threaded ping with all traffic forced over the VPN, I figure out the proper range of IP addresses which should be routed through the VPN. I then add those newly discovered routes to my script.
The above process is annoying. Is there an automated way I can know which IP addresses should be routed through the VPN?
I already have 10.0.0.0/255.0.0.0, 172.16.0.0/255.240.0.0 and 192.168.0.0/255.255.0.0 routed through the VPN. However, I find there are several other IP addresses which must be routed through the VPN in order to view the internal version of the site.