I'm going to connecting two LAN's in some way, I imagine some form of VPN tunnel between the gateway/router on each side. Both routers have Ubuntu-server 10.04 installed, but the only vpn-like experience I have is setting on-demand TCP-port forwarding with ssh, but I want this to work for windows clients as well.
The two networks are only connected through an Internet connection, and I don't want my private traffic exposed (traffic like samba).
So how can I do this?
While we have VPNs at work we usually use cisco tech to build them (although we use linux machines to do some advanced routing before it hits the real routers). So I have no experience using OpenVPN, but a quick google search gives some quite straight forward tutorials. I liked this one.
A VPN is a virtual private network. By definition that makes you traffic protected. It works by encrypting the packets when they are sent over the public network between the gateways.
Therefore, you don't need to be concerned about your traffic. It is protected when going through the tunnel.
If you want to prevent certain traffic to even cross over the tunnel, you can do this by setting up a firewall (or setting the iptables in the appropriate way) such that this particular traffic will not be routed through the vpn interface.
You can set this up by using openvpn as provided in the Ubuntu repositories.
I am still not sure if this is what you are looking for, but this is the best I can answer this question as it is at this time.