External DHCP server

In this recipe, we will configure a bridged OpenVPN server so that it uses an external DHCP server to assign addresses to the OpenVPN clients to further increase the integration of remote clients with the clients already present on the server-side LAN.

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 and OpenVPN 2.1.1. The client was running Windows XP SP3 and OpenVPN 2.1.1. For this client, keep the client configuration file, example3-2-client2.ovpn, from the recipe Enabling client-to-client traffic at hand.

How to do it...

1. Create the server configuration file:

   proto udp
   port 1194
   dev tap0
   
   server-bridge
   push "route 0.0.0.0 255.255.255.255 net_gateway"
   
   ca       /etc/openvpn/cookbook/ca.crt
   cert     /etc/openvpn/cookbook/server.crt
   key      /etc/openvpn/cookbook/server.key
   dh       /etc/openvpn/cookbook...