A very common use of a VPN is to route all the traffic over a secure tunnel. This allows one to safely access a network or even the Internet itself from within a "hostile" environment (for example, a poorly protected, but properly trojaned Internet caféteria).
In this recipe, we will set up OpenVPN to do exactly this. This recipe is very similar to the Server-side routing recipe, but there are some pitfalls when redirecting all the traffic over a VPN tunnel.
The network layout used in this recipe is the same as in the recipe Server-side routing. This recipe uses the PKI files created in the first recipe of this chapter. For this recipe, the server computer was running CentOS 5 Linux and OpenVPN 2.1.1. The client was running Fedora 13 Linux and OpenVPN 2.1.1. Keep the configuration file, basic-udp-server.conf, from the recipe Server-side routing at hand, as well as the client configuration file, basic-udp-client.conf.