OpenVPN debugging

I have a working OpenVPN site-to-site configuration (client: OpenWRT, server: Ubuntu). The problem is that when I connect with my laptop from a 3rd place with normal OpenVPN client under Windows (I get another IP address), the following happens: - ping from OpenWRT -> Ubuntu stops - ping still works from Ubuntu -> OpenWRT - ping works from Windows -> Ubuntu Your job would be to find out what causes the problem. I want to be able to connect from Windows using OpenVPN client without causing any damage to the already working OpenWRT -> Ubuntu configuration. You will receive: - OpenWRT OpenVPN client config - OpenWRT iptables config (simple file) - Ubuntu OpenVPN server config - Ubuntu iptables config (simple file) - A test OpenVPN client pack for connecting from a third place I will setup an e-mail to your address that notifies you if there is a problem with the connection of OpenWRT -> Ubuntu. If needed, we can interact through Skype, Viber or anything, I can give you information. I cannot give you direct access to the OpenWRT or Ubuntu, but I can share screen if needed. The problem might be an iptables issue... The project is finished when you tell me what caused the problem exactly and also give me a solution for the future (and of course I try it and it works)! I need someone who has great knowledge with OpenVPN setup and iptables.