Bridging—Linux

This recipe will demonstrate how to set up a bridged OpenVPN server. In this mode, the local network and the VPN network are bridged, which means that all the traffic from one network is forwarded to the other and vice versa.

This setup is often used to securely connect remote clients to a Windows-based LAN, but it is quite hard to get it right. In almost all cases, it suffices to use a TUN-style network with a local WINS server on the OpenVPN server itself. A bridged VPN does have its advantages, however, that will become apparent in the next few recipes.

However, there are also disadvantages to using bridging, especially in terms of performance: the performance of a bridged 100 Mbps Ethernet adapter is about half the performance of a non-bridged adapter.

Getting ready

We use the following network layout:

Set up the client and server certificates using the first recipe from Chapter 2, Client-server IP-only networks. For this recipe, the server computer was running Fedora 12 Linux...