Configuring the router
You are going to need to make some changes to the settings for the router that is running on the home network and that is attached to your OpenVPN server. The particular router I used for testing is a Linksys WRT54G version 1.1 running Sveasoft’s Alchemy firmware. You will need a router that is capable of updating itself to DynDNS.org or some other service if you have a dynamic IP address.
You'll also need to make sure that the port you configured OpenVPN to listen on is forwarded on the router to the IP address of your server. On the WRT54G, port-forwarding is configured in the "Applications & Gaming" section. Enter 1194 for the port, UDP for the protocol, and 192.168.1.150 for the IP address. Make sure the entry is enabled and then save the setting.
Next, you need to add an entry to the router’s Routing Table. This will enable the router to properly route requests from the clients to the TAP interface of the server.
On the WRT54G, you would go to the "Setup page and then the "Advanced Routing" section.
Enter the following info to make the entry:
Enter Route Name: openVPN Destination LAN IP: 192.168.10.0 Subnet Mask: 255.255.255.252 Default Gateway: 192.168.1.150 Interface: LAN & Wireless
Once the info has been typed in make sure you save the setting.