[Halt]

My personal rule of port forwarding for Source engine is starting at 27015 and opening by increments of 5. You don't want ports to close to one another. Example:

Server 1 ip:27015
Server 2 ip:27020
Server 3 ip:27025

And what I said earlier was if your VPS is on your VPN in other words your server is on your virtual private network.