Help with VPN

[wfczservers]

I bought the linux vps and I downloaded openvpn on it. I logon my vpn through my computer with openvpn and I share my network with my pc through the networking options with my xbox 360. When I try to host a lobby on black ops it just keeps loading and I get some people in that join the lobby but by the time it fills up they leave it takes like 20 mins to find someone. On my old vpn I was using it was instant connection and people would join my lobby like that. They told me it was a problem with the firewall or the ddos protection keeping out some of those connections. I was trying to find a fix for this anyone?